How to collide fluids to form vortex I want to simulate two fluids shearing past each other, to show that they form a vortex naturally. (That is, I don't want to put an artificial vortex to make the fluids rotate. I want it to happen as a natural result of the physics simulation.) I don't need to render it, but I would like to have it show the velocity of the particles, as done in the tutorial below.

I followed the technique in Maxim Sachs' tutorial on YouTube on how to do Fluid Flow Simulations. I made an emitter of particles and set its physics to "fluid." I duplicated it, flipped it 180 degrees and aimed it at the first emitter. (So that both fluids belong to the same particle system.) But when I animate it, the fluids flow past each other as if neither was there. (That is, no collisions between the two particle systems.)

Can such a simulation be done in Blender and what's the trick to allowing the two fluids to interact?

====
Update: Since asking the question, I've tried another tack. I am using a fluid domain and created two inflow volumes. I get some mixing that way, although I haven't gotten parameters right to get a vortex yet. But even if I get the vortex, I don't see a way to color the two inflows. Blender sees the fluids one (probably related to doing it all in the domain.) I've tried coloring the inflows with red and green materials, but no difference.

You cannot visualize vortex with fluid simulation voxel data, because there is nothing moving inside the fluid mesh, it all happens on the fluid's surface.

You would have to use 2 interacting domains and form the vortex with their interface by mixing them. This cannot be done in Blender since multiple domains cannot interact. You can simulate only 1 domain in scene, although you can playback multiple domains from baked files in single scene.

There are Trace particles for visualizing the movement of voxel liquid. Add some dummy mesh object (plane) into scene, enable fluid and set type to Particle and check Tracer. Under Domain > Fluid Particles set their count. But these particles are not always behaving nice (they stick to walls, play dead).

So you might want to use SPH Fluid Particle simulation instead and get a very nice vortex. If you mesh these particles with the CubeSurface addon you could also color the opposing streams differently so the render will be nice.


Created concrete material by following a 2.79 tutorial in 2.8 and messed up true displacement Here's the tutorial I followed:

https://youtu.be/wmtAVNDtc_w

The only change I made was i skipped a portion with the image texture around 5:30 because i didn't find any major change without it and he youtuber didn't provide any link for the image. So now I'm left with a mesh that ignores true displacement in eevee and takes it too far in cycles

here are some screens links as the page isnt allowing me to upload them directly:
https://photos.app.goo.gl/FPrTejKkSQqiCWVdA

And here is the blender file:

Due to adding vector displacement not so long ago to Blender you have to use dedicated displacement node to convert scalar to vector displacement.

I would say that your shader structure is outdated. It is better to mix RGBs instead of shaders, and use Principled BSDF instead of mixing Diffuse and Glossy. Take a look at the blend file. Although this is not the best example to demonstrate the superiority of the approach, I changed it so it would reflect the idea without altering the artistic component. The shader became heavier but more realistic and PBR.


Correct mistakenly changing mouse select to left button When I installed 2.81 I mistakenly chose select with left button. I use the mouse with my left hand and actually want to select with right button. My Preferences>Input does not have a provision to change this. My download is named /blender-2.81a-linux-glibc217-x86_64. Is there a work around?

(I have two previous versions of Blender installed and when I used them I selected with the left button.)

Head over to the Keymap tab and you'll find the select options under Preferences


What am I doing wrong with my rigged body? I just started "playing" with blender after realising that I have to be able to design my own objects to make my own game without keep on using someone else's work/Unity Asset store prefabs. I never designed anything so, yeah, I can say I'm pretty horrible at it.

Everything was going somewhat fine but I don't know why my character's body is not moving smoothly at all. Could you tell me if I'm doing something wrong please?

Here's a video showing the current issue (I know I can use the paint brush to correct the distorted shapes when I rotate the figure but I'm pretty sure I screwed up somewhere with the armature movement part as it lacks smoothness)

EDIT: Here's a download link if you want to see my file:

Deactivate the Snap option (magnet icon on the horizontal bottom bar of your 3D view).


How to distribute objects ONLY on vertex groups in geometry nodes? Thought this would be easy but have been struggling so much with this.
I have created vertex groups (indicated with red color) on a big terrain plane and now I'm trying to distribute objects only inside those areas. I tried adding the vertex group in the Density Attribute but it seems that it's using the weight of the group and it does not have a hard edge so the objects are leaking outside of the area.
Any ideas how to achieve this easily?

OK It's the final edit. I promise
This method works in blender 2.93 Alpha(I don't know about version 2.92)
All you have to do is set the density attribute to material_index and voila your work is done, no weight paint required, it assigns density on the basis of material used.
Screenshot:


The interface to create material looks different When i add a material to my object i get an panel that is like the one from [picture left] but what i need is an panel that is similar to [picture right]. Why is there a difference and how can i get the right one?

Switch from Blender Render to Blender Cycles, top of the main interface. That's your main problem - You're working in the old render engine.

Then... You have to set up a bunch of nodes in the node editor - Specifically a Glossy and Diffuse shader going into a Mix shader, which goes to the mesh's material output.


Where do the white lines come from in my composite? I'm having this issue for years now, and I'm not sure if I am doing something wrong on my end, or if what I would like to achieve - or expect to see - is even possible. My question is about compositing artifacts when using Blenders mask layers. Let me explain:

In the Blend file provided, there are two objects: Dragon A and B. Each of them is on a separate layer, rendered on a separate render layer, and masked with the other one. So A is masked out by B, and B is masked out by A. Like this:

scene setup

RenderLayers A and B

When I render, I write out two MultiLayer EXRs with 16bit depth. That Stuff, I feed into the following comp:

and it gives me this:

You can clearly see the white lines around the areas where the dragons mask each other.

If I comp in a weird fashion like this:

I get this:

It's not perfect, but still a lot better than the first one. What I am doing is kind of cutting off the bright alpha values, making a 0.75 alpha value equal 1.

My question is: Why do I see the white background shine through after all? Is it something which is fundamentally unchangeable and we have to live with? Am I doing something wrong on my side? Do you have an alternative solution?

Edit

The solution Ray Mairlot came up with solves the issue by only masking one of the two, the other one would exist un-masked underneath, and thus provides a perfect overlay. However, I'd like to still mask one against the other for specific reasons: I'm sending images to a web application, which layers them dynamically (a configurator in essence). There can be 30 or more image layers, each of them needs to be downloaded by the website visitor. If I could mask one part against the other, the individual file size would be smaller. Not really a necessary reason, but that's why the idea came up. The other reason is, if I mask the layers, the individual layers render faster. This can save me some 30% of the render time per configurator (which renders on average for 12 hours).

Those two images you're trying to composite together have "correlated" alphas. The Alpha over operation isn't the appropriate operation for this situation.

The solution is simple: you just have to add those images together, then add their alphas together and assign the resulting alpha to the result of the first addition.

Here's how:

Why alpha-over doesn't work

Alpha over is, like its name states, an "over" operation. Something is over something else, covering it. The alpha channel determines the occlusion of the background by the foreground.

When you inspect the alpha-over formula for two associated (premultiplied) images, you'll see it's just an addition, but before that addition the alpha channel of the foreground is inverted and multiplied on the background, casting a shadow on the pixels that the foreground occludes.

Associated Alpha Over Operation:

Foreground.RGB + ( ( 1.0 - Foreground.Alpha ) * Background.RGB )

Porter Duff Alpha Merge Operation Uncorrelated Geometry:

Alpha.A + Alpha.B - ( Alpha.A * Alpha.B )

Correlated Geometry:

Alpha.A + Alpha.B

When alphas are correlated, like in your example, there is no foreground-background situation. It's rather filling a hole in one image with the other image.

The hole and the image that will cover it fit perfectly, so there is no reason for casting a shadow on the background. There's already a hole in it.
If you use alpha over, the "shadow" of the foreground will be multiplied again on the antialias pixels that are already shadowed by the mask, causing a doubled value of transparency, and that's why you get those semi-transparent pixels where they should be completely opaque.

So, skipping the "over" part by just adding the two plates together works perfectly. In Blender you have to add alphas too and assign the result to the mix.


How to join only two objects to create a new object using Python I have a total of 7 objects with the 'Cube' as my active object -
'Cube', 'Camera', 'Light', 'A', 'B', 'C', 'D'

My main objective is to join A, B, C, D between them and create new objects. It is more like a combination problem. Thus, I will have six NEW joined objects along with the previous 7.
AB, AC, AD, BC, BD, CD

I am getting the objects of my interests by the following way
obs = [e for e in bpy.data.objects if e.type == 'MESH' and e != bpy.data.objects['Cube']]

# deselect every active object first
bpy.ops.object.select_all(action='DESELECT')

Now I have the objects and every active object deselected, how can I join two objects at a time without deleting or joining on the original objects?
Blender Version: 2.83

This will work only if all your objects share the same origin and have their transforms applied. Otherwise you will have to convert them using their transform matrices.
Similar to this answer.
We will use itertoolsand itertools.combinations to generate the wanted combinations.
Reference

Then use the bmesh module to concatenate the meshes. (Very important that all transforms be applied and origin at 0,0,0 !)
import bpy
import bmesh
import itertools

objects = bpy.context.selected_objects # Replace with your objects
objects_combinations = itertools.combinations(objects, 2)

for perm in enumerate(objects_combinations):
    this_perm = perm[1]
    new_mesh = bpy.data.meshes.new(this_perm[0].name + this_perm[1].name)

    new_bm = bmesh.new()
    new_bm.from_mesh(this_perm[0].data)
    new_bm.from_mesh(this_perm[1].data)
    new_bm.to_mesh(new_mesh)

    new_obj = bpy.data.objects.new(this_perm[0].name + this_perm[1].name, new_mesh)

    bpy.context.scene.collection.objects.link(new_obj)

    new_bm.free()

Result :


Boolean Difference not working as expected I'm three days into Blender (and loving it!) so please don't be too harsh.
For my small project I decided to create a lightbulb and I'm struggling with the base. My goal was to model a screw thread contact by subtracting a spiral from a cylinder, but I simply can't make it work.

So this is the base

And this is the spiral that I want to subtract from it

And here is the final result of the Boolean modificator set to Difference.

I know this modificator is funky, but still I just don't get what's going on here.
I would highly appreciate any help with where to look at.

It seems like you added Boolean to both, the Bottom part and the Ring too. Don't add to both of them.

Just add Boolean to the bottom part and pick your Ring thing in it, and change it to Difference.


Aperture Settings not Available in Blender 2.79 I have noticed from other posts that I do not have the aperture settings available.
I am trying to set up depth of fields.
here is a screen shot of my screen....
as you can see the aperture settings are not there like I see on other screen shots.

you need to select the camera and be on the camera section of the properties window.

Aperture settings are available on Cycles only, not in blender internal-


How To Apply New UV Edit to Model So I'm UV Editing when suddenly I discovered that the edits I was making weren't applying to the model in the Layout tab. I was confused and went back to the UV Editing tab and discovered that the edits were being made there. Why is that? Do I have to apply somehow to the material?
Here is the image of the Layout tab

Here is the image of the UV Editing tab (what I want to appear in the Layout tab)

Yes you have to apply the texture. To do this in the Shader Editor add an Image Texture Node and a UV Map node. And then it will apply your mapped texture.
The set up looks like this.


Dual brush function in texture painting? I am wanting to mimic the 'dual brush' function from brush settings in Photoshop, with texture painting in Blender. Essentially, what I am after is the ability to have either two brush textures that I can blend between  in a single stroke, based on pen pressure. Or two whole brushes i can blend between based on pen pressure. Does anyone know if something like this exists?

Fyi, I am trying to recreate Dave Grecko's DG_Main brush from this link: https://youtu.be/-oPp6NE4WL8?t=50

Thanks for any help!

EDIT: Answer is below, thanks! There is a function I can work with to get close enough to what I am after :)

Edit: No, there isn't a way to switch between two textures based on pressure in the brush itself. The example given shows how to switch between two colors with the same mask texture used, which is closer to what the linked video showed at the time mark given. IF you simply want to mix two textures, one can be set to the brush texture and one to the brush texture mask, and use separate mapping.

If the gradient is what you are looking for, here is a quick example of the settings to use with a 'Texture Mask' brush and using a two stop gradient set to pressure.

Here I set an image of a square to the main brush texture calculate alpha, rake and use stucco on brush mask set to 'cutoff' for pressure. I hope this one maybe helps. Square has to be mapped to like 1.60 instead of 1 so that there is visibility of the edges inside the brush sphere.


I made a fully animated character on the wrong scale - what is the easiest way to fix this properly? In theory I'm almost looking for something like importing the file and scaling all distances with a factor X.

I'm using the scene within Unity where I actually can scale on import. The problem is that I really need to have the original Blender file in the right dimensions, because otherwise I will be counteracting when I use this model as a reference in other Blender files etc.

What is the easiest way to achieve this?

The first thing that comes to my mind is selecting your character in Blender, scaling to the appropriate size and then press CTRL+A to and select "Scale" in the menu called Apply that pops up, that basically is setting the scale property in the Transform menu (see pic below) to 1 again, making the new scale the default for your model, then if you import your model again it should have the desired scale. Make sure to scale the rig too of course and apply the scale for that too, but if you did eveything right they should scale together automatically.
Remember also you should do this process everytime before importing your model into a game engine.


Moving a vertex doesn't move the vertex, it just makes another please give me some tips on how to stop the vertex cloning from happening. this only happens around this one single ring or circle. everywhere else is normal.

An additional ring of vertices might have already been created by mistake while you were modelling .This usually happens if you had selected the ring of vertices and tried to extrude by pressing 'E' but didn't move those newly created vertices.If a vertex is placed at the same location as another, then they are called 'doubles', as in double vertices.

Inorder to remove them select all the vertices in edit mode, press space bar to get the search bar and type 'remove doubles'. Alternatively, you can press 'w' in edit mode and find the 'remove doubles' option.

Once you click that, on the top menu bar, you will see info about the doubles that have been removed.


How to make animations for two objects? I have a sword and then a slash effect thing that trails behind it. The effect thing looks like this. I'm using the animation data tab in the NLA editor to create different animations for the sword such as holding, swinging left, swinging down, etc. I want the slash effect thing to not be there unless the sword is actually being swung, and like get bigger until the slash finishes and then shrink back to nothing. The problem is, when I insert keyframes for the effect thing, which is a separate object from the sword, they apply to all animations, so the effect thing will be in the same place whether the sword is being held or swung. Is there a way to associate the keyframes of the sword effect with the actual sword?

Pictures of problem. If I could just get the keys for plane.001 and cube to be  seperate from each other, I would be fine.

I figured it out. You just have to use armatures. What this means is:

create an armature from the create menu Shift+A.
position the bones in the Edit mode.
switch to the pose mode, shift+RMB click on each object and its corresponding bone.
press P to connect them using "bone" from the parent menu.
finally animate the entire armature.


BGE animation property? Is it possible to give an animation frame a property so to say?   I want to hold down a button and play the beginning or first half of my animation.  Call it frame 1-12.   A flipper animation.  IF you hold it down until frame 12 I want frame 12 to trigger the next 12 frames of the 24 frame animation.    Essentially If you dont hold the attack button long enough it wont play the full attack.  Just the wind up frames... Then revert/flipper back to the beginning.      What is a way to accomplish this?

I think I may have an answer for that- but it requires an xbox 360 gamepad. Check out this game if you have a 360 controller...


Symmetrize option doesn't mirror bones on the axis This will seem like a very simple problem, however I have not found a satisfactory answer for it:
I am trying to symmetrize a set of bones. The bones have the ".L" ending and when I symmetrize them they are duplicated as expected. However, they appear in the same place as if I was really duplicating instead of using the symmetrize option.
I would just like to have them appear on the other side of the axis. What am I doing wrong?
Thanks in advance for any help!

Take a look at the following image.
The Arrows are pointing at the Object's Origin, if you move your objects (armatures too) in object mode, the Origin is going to be moved with the object. This origin is the way for Blender to "say" Here is the "Left" and here is the "Right". So, you need to keep that origin in the center, also known as World Origin. If you wanna move an object, like your bones, switch to "Edit Mode, select all the bones, and then move all bones to one side or the other.

Hope that helps.


Having issues with bridging simple edge loop first post here.
I find a strange issue and can't get it right.
I try to 'bridge two edge loops' that have the same amount of tiles. Both are round-is. See pictures..
How can i make this just work?

Cheers
Tuur

Your normals have different directions. You can tell by looking at the shading of the two pieces, whereas the left one has the shadow on the underside, the other one has it on the top.

To clear this up, in Edit Mode, select all faces and hit Shift + N to Recalculate the outside Normals.


Weird problem with faces, black lines I'm making a studio monitor and i'm having trouble with the face selection, vertex. I'm pretty new to blender and 3d, so i think this must be a pretty common error.

Here is the mesh, i want to select the faces were are triangles so i can make them quads

But this happens every time i try to select the face, it select the hole section.

And this is how it looks out of edit mode, full of black lines

This i what happens when i try selecting the vertex of the triangle and using subdivide

Instead of creating triangles and trying to fix them later, keep your topology using quads all the time.

It is a common misconception that the topology of an object comes at the end of the process. The topology of the object should always be worked out from the beginning.

A simplified way to do a speaker:

Start with a cube, scale it on the $Z$ axis, and make a loop cut in the middle.

Position the cut to divide the two main sections of the speaker.

Create some vertical loop cuts And subdivide each of the sections with an equal amount of cuts.

select the edges that will become the round part and press ⇧ Shift+⎇ Alt+S (to sphere) and move the mouse to create a circular shape.

Do the same for the top part.

Select the central faces to extrude.

If you select the loop ring in the front you should be able to bevel the holes.


Restricting rotational movement on my model? Does anyone know how I can keep my model's feet from rotating around it's body in a 360-degree motion, as seen below?

My model's feet are suppose to swing back-and-forth in opposite directions of one another in order to create the appearance of walking.

I've attempted to add a Bone Constraint to see if it was possible to place a restriction on the feet's rotation on the model.  Unfortunately, I haven't had much luck in trying to setup the Bone Constraint, as I can't seem figure out how to properly set up the Bone Constraint in a proper manner.

Any help, as always, would be greatly appreciated.

EDIT: I replaced the original Blend file with a new updated version.

Blend file download:

Sorry, I see a lot of mess in your file, some of the problems: objects don't have loc, rot and scale applied; some objects are parented one to another, you have three different rigs for a single simple character, bones are set to quaternion while animation is on Euler, and so on .....

There is no need of constraints, I think you should get a better understanding of the rigging principles and then start again from scratch.

As usual, there are many methods to reach yout goal, I'll try to illustrate one of them: in this method we don't use vertex groups: every object is directly parented to a bone of a single armature, and the 5 objects stitch together thanks to the armature parent ties.

After the end of modelling process, you have 5 objects: body, foot.L, foot.R, and the two eyes (after applying the mirror modifier).
Unparent (Alt+P) every object one to another, then move and rotate them to their rest position (it can be feets right under the body, in central position)
Select one object and apply (Ctrl+A) location, rotation and scale, so that every object has his origin in 0,0,0 location, 0,0,0 rotation and 1,1,1 scale
Create a new rig with one bone for the body, one bone for the leg.L and one for the leg.R (in your example there is no need for the other four "feets" bones), then, in edit mode, select (in this order) leg.L, leg.R and body bones, <Ctrl+P> and choose "Keep offset" option.
In pose mode select a bone and choose "Euler XYZ" option in the Nproperties tab; do the same with the others 2 bones.
Go to pose mode, select leg.L bone, go to object bone, select the foot.L, shift select the leg.L bone, press Ctrl+P and choose "Bone" option: in this way the whole foot.L object will follow all movements of the the leg.L bone.
do the same with foot.R and body (shift select eyes, body and body bone, in this latter case)
If you move (in pose mode) the body bone, the body object will follow it, and so will do the feets, because leg bones are parented to body bone and feets objects are parented to leg bones.
to program a basic walk cycle go to frame one, rotate the two leg bones in contact position (one forward and one backward), then select all bones and press I and choose rotation option. Go to frame 41 and press i again. go to frame 11 and select all bones press Alt+R to reset the rotation of the bones, then pressi I. Go to frame 31 and press I again. Go to frame 21 and set the legs rotation to the inverted contact position (one backward, the other forward).

Set the cycle from 1 to 40 and GO!

In this way the cycle will be:

1 contact
11 passing
21 inverted contact
31 passing
41 (1 again) contact

If you repeat the cycle, you can then animate the location of the body (which, as seen, will move the whole character).

Good luck and keep it on, I also had lots of headaches in understanding rigging, search Nathan Vegdahl free you tube tutorials for deep understanding of advanced rigging.


How to model a curved book page? I am a noob in blender. I want to create this non-symmetrical curve between the top curve of the page and the bottom curve of the page, but I couldn't find the way to make it.

Is there anyone want to tell me how to make it, or give me some easy tips and a tutorial?

Quite nice result with Cloth Sim + Empty

Under Physics Properties Enable Cloth Simulation, Preset > Rubber > Vertex Mass decrease to 0.3 kg
Create two Vertex Groups, one for Pinning second to Hook Empty

Pinning - select left two line of vertices + right-down vertex, add a new group and assign. Select second line of vertices and lower weight to 0.5

Hook - for this vertex group select only right-down vertex, add a new vertex group and assign

Snap cursor to Selected (Shift+S), go to object mode and add Empty.
Select page and add Hook modifier above Cloth with Object > Empty, Vertex Group > Hook. As a last moodier add Subdivision (with border vertices selected press Shift+E+1 (Crease) to keep sharp edge shapes of page.

Tip: to affect curvature at book binding slide second edge more left or right or add one more edge loop ...


Is there a way to make denoising work in the Cycles viewport? I saw this in other renderers, such as the Radeon ProRender or V-Ray and was wondering if there's an Add-on or Build for Blender to work around the limitations of Cycles' Denoiser.

No, there is not. From the Official Manual Denoising uses render tile information from the engine to make the necessary calculations for the image processing algorithm.

  Denoising filters the resulting image using information (known as
  feature passes) gathered during rendering to get rid of noise, while
  preserving visual detail as well as possible.

  To use the option, enable it in the render layers tab of the
  Properties editor. On rendering, it will denoise tile by tile once all
  the surrounding tiles are finished rendering.

It is not available for progressive renders, and as such doesn't work for viewport previews, which are a form of progressive render.


Blender 2.9 Crashing upon Render using Animation Nodes. Image and Animation Blender 2.9 Crashing upon Render using Animation Nodes. Image and Animation
I am using an RTX 2070 so I don't think it's my GPU and I should have plenty of memory. It is the first time trying to render a scene Utilizing the Animations Nodes ADDON but nothing else is different from past renders. Any insight is appreciated.

Always use the last AN version, at this time it is animation_nodes_v2_2_windows_py37.zip
I also have crashes in 2.91, sometimes after 5 frames rendering, sometimes after 25 frames, so weird, I will check an older Blender version.....okay checking 2.83LTS...rendering for 40 frames now without crashing.
Looking good so far! Please try!
Freddy


Shading Issues after knife project Just starting out in the world of Blender 3d and I am trying to replicate the bottle below but am having difficulty creating the ridges that go around the centre of the bottle.

I have tried a couple of different ways of doing this but am having difficulty in finding any tutorials similar to my needs and also I am not sure on the terminology I need to use in order to search for the issues I'm having.

Attempt 1 (above)

Creating the bottle shape then using the Knife project with 'cut through' selected to create the ridges

then bevelling each individual ridge but have an issue with the shading where the vertical edges meet the bevelled curve on the ridge and in the centre.

Attempt 2 (below)

Creating a cylinder bottle, then again using the knife project with 'cut through' selected to create the ridges

then adding adding a lattice modifier to create the shape of the bottle but again still with the same shading results after adding a bevel.

So my question is am I creating this in the correct way (knife project) and I need clean up the mesh or is there 'simpler' way of creating this?

As I said I am very new to Blender 3d so I apologise for the vagueness of the question but am very keen to learn the correct way of doing things at the start so not to get into bad habits. Any help would be gratefully appreciated.

Try to add additional loop, and leave it on the surface:

It will add transition between main surface and the edges


How to get sponge type material Im trying to get a sponge type material. like this

Uptill now i have tried this.

But my result not near to it.

I know its lot missing anybody help me how to get that material.

I would use a much simpler setup:

Math > Round to make texture black and white and Math > Multiply to control Volume Density.

You can use different textures to get different results, I've made examples above with Noise, Voronoi and Wave.

As always with Volume Shaders don't forget to crank up Ligth Paths > Volume to something more than 0.


Keyframe interpolation instability That's me again, struggling with the animation. I created a number of key frames. However, my camera sometimes was doing a full 360 loop interpolating between two close camera positions. So I had to add more and more key frames to stop it. But in the end I have just one odd frame 114, where it suddenly jumps. In the "Transform" panel under "Rotations" I have "Quaternion (WXYZ)"). All the components of the quaternion are quite small and change its sign between these two frames as I see in the "Transform" panel.

Deleting the key frame 113 causes the camera to roll all over the place again.

Is there a way to stop this behaviour? I also found some posts talking about parenting when creating animations, but I can't understand it exactly.

I checked how it looks in the Graph editor, but rotations are smooth and no sign change at that frame 114. So as far as I understand Graph Editor has rotation in local coordinates, while the transform panel in global.

The animation is here (model from blendswap, made by TheDuckCow):

EDIT:

Here is an example. This frame is fine.

But next one is not:

Then next one is good again.

Apparently something numerical happens when they all go through zero...

This is what happens if I run the script:

Quaternions must be "normalized" in order to represent an actual orientation.  That means 1=w*w+x*x+y*y+z*z.  Fortunately this gets handled for you, and much of the time the result is close enough to what you want that you don't even notice a problem.

However, if the animation system interpolates a value where all of them are zero, then it probably gets changed to <1,0,0,0> .  The only way to solve that problem is to add a keyframe that has the intermediate orientation, preferably in a normalized form.


Combine two normal maps and control the strength of each I use this node setup to combine my two normal maps.

I adapted this method from here.

How to Combine two Normal Maps?

It works perfectly to just combine the maps.
But now i need individual contol over the strength each of them.

Is there a way to do this ?

A more precise result can be found using these formulas...
Here's an adaptation of it including a Factor value for mixing:

some more details can be found in this thread in BA

And the nodegroup can be found here.


Can I have two different UV unwrappings of the same object? Basically, I have two textures, one of which is mostly transparent. I want to combine them, so that they're one on top of the other.

The problem is that one is bigger than the other, so I would need two different UV unwrappings of the same object, one with a bigger scale than the other.

Is it possible to do so or should I combine the textures in an external program?

Yes, it is possible.

In the mesh panel, under UV Maps, press the "+" button. This will create a new UV map with the same coordinates as the existing one.

For Cycles, in the node editor, select Input -> UV Map to use different UV maps for different shader parts.

In Blender Internal, you can select which UV map to use in the texture panels.


How do I get a user defined filepath in Blender with python? I have to allow users of my addon to select a path via the directory browser window of blender.

Instead of using this

I used Operator in panel to get the folder path from user as follows

I tried lot of ways and I referred this and still trying....

Here is my code, for operator to browser the folder and set it.

class OBJECT_OT_find(bpy.types.Operator):
bl_idname = "object.find"
bl_label = "Select Path "

directory = StringProperty(maxlen=1024, subtype='FILE_PATH', options={'HIDDEN', 'SKIP_SAVE'})
filter_image = BoolProperty(default=True, options={'HIDDEN', 'SKIP_SAVE'})
filter_folder = BoolProperty(default=True, options={'HIDDEN', 'SKIP_SAVE'})
filter_glob = StringProperty(default="", options={'HIDDEN', 'SKIP_SAVE'})

def execute(self, context):
    # what to write
    return {'FINISHED'}

def draw(self, context):
    self.layout.operator('file.select_all_toggle')

def invoke(self, context, event):
    wm = context.window_manager
    wm.fileselect_add(self)
    return {'RUNNING_MODAL'}

def register():
 bpy.utils.register_class(OBJECT_OT_find)
 bpy.utils.register_module(__name__)
 bpy.types.Scene.FPath = StringProperty(name="Set Source to Find",
  attr="custompath",
  description="searching Images",
  maxlen= 1024,
  subtype='DIR_PATH',
  default= "")
def unregister():
 bpy.utils.register_class(OBJECT_OT_find)
 bpy.utils.unregister_module(__name__)
 del bpy.types.Scene.FPath

How can I get that path? I want to store and read it.

As far as I know, it's bad practice to create the custom property for the scene in the register function. You can do this in the execute function. Also you shouldn't create it on bpy.types.Scene but on the current scene itself.
For the execute function you can use this code:

def execute(self, context):
    d = self.properties.directory
    bpy.context.scene['image_filepath'] = d   #store the path for later use
    [...]
    return {'FINISHED'}

You only need the bpy.context.scene['image_filepath'] = d if you want to store the path for later use.

You can simplify your register and unregister functions:

def register():
    bpy.utils.register_module(__name__)

def unregister():
    bpy.utils.unregister_module(__name__)

You can now run your operator and choose a folder to do something with. If you later want to access the path to the folder you can use bpy.context.scene['image_filepath'].


How can I make a sound wave effect on a "wall" of cubes through animation nodes? I want to make an effect of a wall of hexagons (just cubes) move in and out at different points simultaneously, almost like if it had an ocean modifier, or could textrue displacement on a plane, but i want the objects to be individual. doing this with the particle system can be annoying at times to where i have not gotten an acceptable result. I saw a demo on youtube where someone used a random object to push on the cubes with a proximity node in the animation nodes part of blender. I just downloaded animation nodes recently and the nodes he used are no longer in the animation tree, probably because it's been 2 years since the video was made. anyone know how to create the proximity effect with the (2017) current animation node set up?

Without using animation nodes you can create a subdivided plane and make it the parent of a cube, then enable dupliverts on the plane to have an instance of the cube at each vertex. As you deform the plane the duplicates will move with each vertex.

To your question of using animation nodes - A Grid Mesh node will give you an array of vertices that you can use for the location of duplicates, while an Object Instancer node will make the duplicates, then use a subprogram to adjust each duplicate. You create a subprogram to be able to repeat a node setup for each item in a list.

Add a loop subprogram - A->Subprograms->Loop
On the Loop Input node add two iterators, one as an object list, the other a vector list.
Add an invoke node with A->Subprograms->My Loop (unless you renamed it), the Invoke Subprogram node will have input sockets for each iterator you have added.
Connect the output of the object instancer to the object list input of the Invoke node.
Connect the vertices from the Grid Mesh to the vector list input of the Invoke node.
Add an Object Transforms Output node.
Enable the location checkboxes to get an input socket for location.
Connect the Loop Input object to the object input of the Transforms Output node.
Connect the vector from the Loop Input to the location input of the Transforms Output node.

Now that you have the duplicates in place you connect in other nodes to alter the location. In this example I use separate and combine vector nodes and add in a number wiggle to alter the z location.

To get the distance between two objects there is a distance node -

Zach Hixson has recently started a tutorial series for animation nodes, you may want to have a look at his playlist


Errors creating .stl file I am trying to print a small model for a class project.

There were errors when I originally tried to export the stl file, which is here.
https://drive.google.com/open?id=1Xuo7fPLtYH7GmFApBSuaffNCXg-nyn-O
(Wasn't sure how to copy the error log else I would post it here). I opened it in slic3er and it appeared, but it slic3er was stuck processing the triangulated mesh. I took it to the print shop hoping they could help me but it did not show up at all in their slicer program.

I decided to start the model over, since it was just made from an svg file I made and shouldn't take long. Tried to do a boolean union operator between the base and the logo since you cannot have intersecting objects for prints, but it just keeps crashing every time. Found another stack exchange that had the same problem because of non-manifold vertices. I think I checked mine and found nothing. Tried to run the 3D Print add-on and did not see any errors with that.

Here is the current re-done .blend file.
https://drive.google.com/open?id=1jK6VZ5eToYQe2SryE1z38dvz1iU-rTtk

In the blend file from the link above the main reason for problems with 3D printing is going to be standard cases of non-manifold geometry.

There are a lot of areas with overlapping geometry with multiple vertices in the same place:

These will cause errors because of interesecting geometry. It can be previewed with enabling Intersect geometry for real-time preview in the Properties shelf > Mesh Analysis rollout (available in Edit mode):

As there are many places with such tiny errors it's easier to fix them all at once; first off in Edit mode with all selected use Remove Doubles command to get rid of duplicated vertices. Note to set threshsold quite small, like 0,000001 as otherwise there will be some changes in the letters form (tiny changes though).

After ~1200 vertces removed run Ctrl+Alt+Shift+M or Select > Select All By Trait > Non-Manifold from 3D viewport header. There will be some vertices selected in the area in '8' digit:

There could be some overlapping faces left next to faces with inconsistent normals. Check if there are and remove doubles once again if needed; in general the only thing left is to recalculate normals there with Ctrl+N (or with all selected).


How to shoot a character from one platform to another. (BGE) So my character (character physics) will be traveling through the level and I want him to be able to jump into a cannon of sorts, and when a button is pushed, he gets fired upwards along a parabolic path to another platform to make the level more interesting. I've tried making an invisible platform that carries him quickly, but it doesn't work and is really hard to make anyway. I am obviously new to blender, so it feels like there is a very simple solution that I'm just not finding.... Thanks!

Final result:

What's happening

So I have a player, a floor for the player to walk on, a wall to jump over, and a cannon to launch him.

The player has a basic setup:

W to move forward, A to turn left, S to move backward, and so on.
The motion of the Dynamic player is simply the Location of the Motion Actuator.
(You probably have a different setup)

Now, inside the cannon, I added a child cube, that I'm calling inside. It's static and has the cannon as a parent. It's also Invisible and has the Ghost property applied.

The logic bricks

Referencing the above image, when the player comes into contact with the inside cube, the keyboard sensors will activate. When A is pressed, they will activate the cannon's Motion Actuator, that will turn the cannon 2 degrees along the Global Z axis. Likewise, when D is pressed, it will move -2 degrees.

Last of all, when the Spacebar is pressed while in contact with the inside cube, the Player's Motion Actuator is triggered with a force of 800 along the Z axis. Because the cannon is slanted, the player will hit the top of the cannon and will be forced out of the cannon at the same angle. This will not work if your cannon is vertical.

Here is the .blend file:


I am not able to curve a plane using array and curve modifier using a curve I used a curve and plane and created a path curve and arrayed the plane then added a curve modifier and when edit the curve to curve it distorts the whole mesh of plane.

Sorry but can't udnerstand what you need. But if you wan't to distort the plane along the curve you must subdivide it. Press Tab to enter Edit mode and right click and choose subdivide.


Stamp plane UV onto a mesh Im using blender to change some premade assets for our game. I want to move a window. Here is the original mesh and UV The texture is planar and flat so it matches 1:1 to the shape of the 4 outer vertices on the mesh.

Here is the new mesh, I have tried to manully adjust the window UV mapping. But get errors

But offcourse I end up with errors, here in Unity

There is probably a super easy solution to this, sorry for being a noob

The distortion you are seeing is the result of the mesh and the UV maps not sharing the same proportions. Here is one method for achieving your desired effect, but it assumes that your texture is only for the wall, and that the four vertices of the window don't have to be in a specific place on the texture.

In Edit Mode, press Shift+D with your mesh selected to duplicate it.
Move the window to the desired position.
With the duplicate selected, press U to unwrap it.
With both meshes selected so you can see them unwrapped, position the newly unwrapped mesh above the old one. This can be achieved in a number of ways, but one ways is as follows:

Select old wall's bottom left vertex on the UV map, and move the cursor to the selection.
Using Vertex Snap: Closest, position the new wall on the UV map such its bottom left vertex aligns with the old wall's.
Set the pivot point to cursor, and scale the newly unwrapped wall until all of its vertices align with the old wall. Make sure you are always scaling the whole wall, including the window vertices.


Detail from multires and mirror object I have a mirrored object with a multires modifier. When i apply the mirror modifier in a lower Level the higher multires Level are lost when i apply it in a higher Level the mirror is not closing all the gabs in the middle... I checked it in edit mode everything is in the middle but still not working..(increasing the merge Limit will also not help because the mesh is not even)I also tried baking a displacment map which works kinda well but one part was not good and i had to exclude it with weight paint but then it is just at Level one and Looks ugle.. also the seam is bad.. hope someone can help?

You can try this way.

Add -> Mesh -> Plane

Select the Multires mesh and in the Mirror tab -> Mirror Object-> Plane

Select the plane and adjust the center part moving the plane in x axis in my condition


IK constraint not working This is the robot rig that I am working on. I duplicated the left leg to make an FK IK switch. But the IK is not working on the "Third leg part L.002". I tried to move the IK control bone, which is "Foot L.002", but I am not able to. I can only rotate it and it is not controlling the other bones.
Here is my blender file https://www.mediafire.com/file/bero482tlud01xo/robot_v2_-_rig_-_controls.blend/file

You have to unlock your controller bone loc channels.


how do i removed orphan linked material I have two materials that I linked from another file  and I can't figure out how to delete them. As you can see, both HairMix and VariableMaterial show LF in the search box. They do not go away when I close and reopen, because of the F state. How do I remove them?  [edited in response to a comment pointing out that the original question was invalid because I had misunderstood L to mean locked, rather than linked.]

You can delete the material by right-clicking on it and selecting delete from the pop-up menu. This won't affect them in the other file, it just removes them from the one you are working on.


Parent with automatic weights problem in Blender I am rigging a character for an animated short in Blender 2.82, but then this happend:

On the other hand it looks as it shouldt, but here something went wrong. Do anyone know what I did wrong?

EDIT: I found the solution! I had already parentet the mesh to the armature erlier. Later I flipped the names from L to R. Then I parentet it again, and it had still saved some of the old vertex groups. I deleted all the vertex groups, and now it works:)


Why can I not render a displacement map animation? I've followed a Gleb Alexandrov tutorial (2.77) up to this point, using Blender 2.82. However, I can't seem to get Cycles to render the required displacement maps. Can anybody tell me how to get over this hump?

You should be able to download my .blend here!

Baked the dynamics of the canvas, switched renderer to Eevee and it worked fine. =/


How to make CUDA work in Ubuntu so as to enable GPU rendering in Blender? I have installed Blender 2.78c and I would like to make Cycles and LuxRender render with GPU on my GeForce GTX 760M. In Windows it works perfectly, but in Ubuntu 16.04 and 17.04 it doesn't allow me to select GPU rendering for Cycles on "user preferences > system" and LuxRender shows me the following error message in the log tab when I select any LuxCore rendering mode:
OpenCL ERROR: clGetPlatformIDs(-1001)

I have already installed NVIDIA drivers, nvidia-cuda-toolkit and nvidia-modprobe from the official repositories, as suggested in other topics, tried to run Blender as root, but nothing changes. From the list of installed packages, I get:

nvidia-375/zesty-updates,zesty-security,now 375.66-0ubuntu0.17.04.1 amd64  [installiert]
nvidia-cuda-dev/zesty,now 8.0.44-3 amd64  [Installiert,automatisch]
nvidia-cuda-doc/zesty,zesty,now 8.0.44-3 all  [Installiert,automatisch]
nvidia-cuda-gdb/zesty,now 8.0.44-3 amd64  [Installiert,automatisch]
nvidia-cuda-toolkit/zesty,now 8.0.44-3 amd64  [installiert]
nvidia-modprobe/zesty,now 375.26-1 amd64  [installiert]
nvidia-opencl-dev/zesty,now 8.0.44-3 amd64  [Installiert,automatisch]
nvidia-opencl-icd-375/zesty-updates,zesty-security,now 375.66-0ubuntu0.17.04.1 amd64  [Installiert,automatisch]
nvidia-prime/zesty,now 0.8.4 amd64  [Installiert,automatisch]
nvidia-profiler/zesty,now 8.0.44-3 amd64  [Installiert,automatisch]
nvidia-settings/zesty,now 381.22-0ubuntu0~gpu17.04.1 amd64  [Installiert,automatisch]
nvidia-visual-profiler/zesty,now 8.0.44-3 amd64  [Installiert,automatisch]

What should I do? Why does it work in the Windows installation and not in Ubuntu?

After long trying I could solve this problem

I found out that my NVIDIA card was not being recognized by the NVIDIA driver I had installed. So NVIDIA X server settings was "empty" like in this thread: https://ubuntuforums.org/showthread.php?t=2342538 but it was recognized by Ubuntu, what I could see by entering the command lspci -nn | grep '\[03' in terminal and getting PCI info about the "3D Controller".

But if I ran prime-select query in terminal I was getting unknown. My Laptop has a NVIDIA and an Intel card and I thought NVIDIA was working because I had graphical acceleration, but I think it was the whole time using the Intel controller. Tried to change the output by typing sudo prime-select nvidia and then I got nvidia by checking prime-select again. But if I restarted the system it was again unknown and nvidia-settings remained empty. I followed all helps I found in forums or stackexchange posts and my problem wasn't solved.

The solution that worked for me was uninstalling NVIDIA drives completely (did this several times) and installing nvidia drivers in a specific order:
First Ctrl+Alt+F1 to enter the tty and then:

sudo service lightdm stop # to kill the user interface process
sudo apt purge nvidia-* # to remove all nvidia packages
sudo dpkg --get-selections | grep nvidia # check that no nvidia packages remain
sudo add-apt-repository ppa:graphics-drivers/ppa # if you still didn't add it
sudo apt update
sudo apt install nvidia-375 # installed the NVIDIA drivers v.375.66
sudo apt install nvidia-prime nvidia-settings # Probably already installed
sudo apt install nvidia-cuda-toolkit # if you want to use CUDA
sudo apt install nvidia-modprobe

when restarting I disabled IEFI secure boot in the secure boot blue screen. After doing everything the NVIDIA card was not recognized yet. So I went to the tab "additional drivers" on the software-properties-gtk (just type this in terminal to open) and selected the driver Nvidia version 340.102 (proprietary) and clicked apply changes. After rebooting the machine again the card was recognized by NVIDIA X server settings (or nvidia-settings) and everything worked fine, Blender recognized CUDA and so on. I just don't understand why NVIDIA put my GeForce GTX 760M in the list of supported cards for the drivers version 340, 375 and so on, but actually just one (or some) of them works, in my case this (older?) version nvidia-340. I had already tried to install nvidia-340 directly from the repository and also select it in additional drivers without previous installation. It should have worked, but it hasn't.

Conclusions: the nvidia drivers for Linux are there, but it's a huge mess! Ubuntu does its job fine by recognizing it with the command List PCI lspci, but the nvidia support is messy and unclear with this several versions. So, if you still have problems on making your card work, try to install different propietary driver versions or select them from the additional drivers list. Maybe the driver you tried to use is actually not the one that works with your graphics card. Let's see if NVIDIA decides to make that better and start to opensource their drivers!


Material and Texture to Achieve an appearance How to do this in Blender render:
https://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Every_Material_Known_to_Man/Light_Effects

Settings are there but I couldn't recreated it because some of them were replaced with new ones.

I need B.render because I'm using halo material specific in the scene.
Thanks

I want to look like this

EDIT:
Still need a bit of tweak. How to get this white color on top of the wave ?
https://dl.dropboxusercontent.com/u/13451287/bsphere.blend

Here is a modest sloppy facsimile at the end of the post.

You must adjust to taste and artistry.
I am trying to show a technique and you can run free from there.
I am not using the exact same settings as the old manual.
I am not using Fresnel.

Blender Render. Please note there are no lights in the image below.
Shadeless Material and Texture Mapping Coordinates [Normal] with an Radial Gradiant Image.

Here is a material setting
Note the shadeless and transparency

Here is a texture setting. Note the coordinates are [Normal].  The circular image with transparency. The color ramp to threshold color.

Note that the alpha is modified.

Note the circular image which is transparent in middle.
This can be created in GIMP or Blender.  The color ramp modifies the intensity of this image.  Modify all to suit your tastes.

Some experiments to show some use of the color ramp.

Below we see transparency.  The Mapping Coordinates is (Geometric Surface) [Normal].  Exaggerated white colors.
Note the color ramp with the Red Marker.  You may change that to blue.

Please experiment and know my circular image could be simplified by you.


How would I make an indent that runs on all sides of the object? I'm trying to make an old PC monitor and there is a seam that runs all around. I tried Extruding inwards but since it runs on all sides it just goes in one direction. Sorry.. still learning Blender. What should I do?

Also should I be using inset and extrude for the smaller heat vents? Or is there a better way to go about it?

You can simply Inset the faces

Select your loop
Inset it by 0, set depth as desired
Check Offset Even


How does Blender lights work in Cycles regarding intensity? The scene:

Just a plane, a camera, and a light.
The plane is facing the camera, the lamp is facing the plane, all 3 completely aligned.
The plane is just a diffuse, R,G,B=1,1,1 which means the material bring back the light it received with the same intensity.
The light has a size of 10cm, R,G,B=1,1,1 and strength of 10, I've tried each type (spot, area...) put a fall off node in constant (which for me and blender manual means, light intensity remain the same regardless the distance it travels).

Render result:

So when I hit render and analyze the scene linear value, I expect to have a value of 10 for the lighted pixels, but I've got pixels around R,G,B=0.25,0.25,0.25 or 0.7,0.7,0.7 depending on the type.

Even worst I've constated that the light is stronger when set to quadratic than to constant, but not close to 10 neither.

I've tried with only the world background R,G,B=1,1,1 and strength to 10, this time the result is as I expected, analyzed lighted pixels R,G,B=10,10,10

Question:

So the question is how do these lights work in cycles, and are they broken?

Edit :

Look Mike's answer and my comment below to see why there's nothing to worry about these lights in Cycles.

Edit2 :

I offert the bounty to Bertmoog because he provide a good in deep answer, in fact, if it was possible, I would have split the bounty 50/50 with Mike, because he point me to the fact that W/m² aren't the same as pixels values, which was an important part to understand why I haven't got the same values for the source and for the mesured pixel (ray intensity).
Thanks to both of you.

The light energy in Cycles are defined using the following unit: According to the doc: "Sun lamps are specified in Watts/m^2, other lamps are specified in Watts, and Emission shaders on meshes are also in Watts/m^2. I am not sure how the world energy is defined.

Because the energy are specified in watts (over an area when applicable), I don't see any reason why a perfectly diffuse surface should reflect the same numerical RGB value as the lamp's energy.


How to delete rigid body cache? I can't delete rigid body cache from scene. When I delete old objects and add new ones they are acting like the old objects. I tried all options under rigid body cache panel in scene properties, Free bake, Bake All Dynamics and others but none of them is working. I wonder how can I delete old rigid body cache from scene?

Under the menu: Scene selection > Rigid Body World > Rigid Body Cache > Free All Bakes > Reset Start and End > Bake

This worked for me in 2.74. It took less than a minute to bake 325 frames.


Why am I unable to color my volumetric clouds white? I am trying to render a cover of white clouds as seen from above. I am using the Principled Volume shader, using gradient and noise textures. It now looks as follows:

However, the clouds are very dark (even though I set the color to white), and I don't know how to change this. I put a purple sun light with maximum strength right above, but it only colors some contours. I've also tried HDR environment maps. How can I get the clouds to be white, just like real life clouds on a sunny day?

After replicating your node network I found reducing the anisitropy value on the principled volume node makes the clouds whiter


Reflections showing wave pattern after adding plane We actually it is quite hard to describe my problem with only using words.
1

My problem is this weird wavy contour. Without the plane underneath the can, the reflections look fine (like in the bottom part), but even when I use the standard Glossy BSDF on the can and a plane with Diffuse BSDF this problem occurs.
Using a higher roughness on the can doesn't change much except that the border between the black part and the correctly reflecting part becomes less prominent.
I am using two area lamps that are lighting every other object correctly.

In this I am using a HDR image for world lighting and a plane without any specific material and now the bottom part doesn't reflect like it should.

Also, the mesh isn't faulty or something in that particular place and if I look at the can from another angle the intersection moves.

I would like to know what I did wrong and I'd be glad for your help.

This is the proper reflection of a curved surface. the peaks of the wave pattern are actually just the corners of the plane.

you could reduce the effects by changing the camera angle or the size of the plane. maybe it helps adding walls and making the plane more of a rectangle than a perfect square.

And the reflections aren't wrong in your second image. the bottom part is just the reflection of the plane.


Show Multiple Weights I would like to see multiple weights and not just the active bone why in weight painting mode you can only see 1 at a time it's kinda annoying clicking back and fourth just to compare is there a modifier or something to fix this?

You cannot see simultaneously two weight influences. I don't know how that can be possible to see on the same mesh as they may overlap.

Though, even if that does not answer the question, you can use the "multi paint" option in the drawing toolshelf.

As indicated in the tool tip, that allows to paint over the selected bones and maintaining their relative influence.

So the paint will affect these bones so that they stay relatively the same between them but change relatively to the other (non selected) bones.

But doing that you cannot compare them, as, as you can see the color shown here is homogeneous.

What you can do, though is opening two views, one with your model, one with UV image editor and proceed to an opengl rendering:


Accessing image texture uv channel connected to Cycles material Image Texture Trying to figure out how to read the uv channel used by an Image Texture input from Python. So, in effect, how to access the "Vector", then grab the attribute name:

You need to use a UV Map node:

You use it like this:


Rendering fire animations with transparent background I'm creating a simple fireball sprite for my game and I want to render a fire animation.

I would like to get the upper images with transparent background, but when is set the transparency on under Render -> Film one of my frames will look like lower pictures.

You can see the difference of these two images.

Blender's viewer is broken for that kind of images, so it's possible that your fire is rendered properly but the viewer isn't showing it correctly when you activated the "transparent" checkbox.
Try to switch the channels preview setting in the viewer from "color and alpha" (RGBA) to "color" (RGB).

If after doing that you can see the fire on black background, then your output is ok. (The ball occludes and emits, while the fire only emits.)
The next step is making sure that you're exporting the image correctly: You'll have to use a format that supports associated alpha. As @mentalist mentioned, EXR is one of those formats.
You'll have to make sure that the program where you're going to use that sprite supports EXR and associated alpha images, otherwise it won't be composited properly.
Keep in mind that PNG won't work for that, as it uses unassociated alpha.
EDIT:
On version 2.92 the viewer has been fixed, so you can see the proper associated alpha.


RuntimeError: internal error setting the array I'm trying to write a function to create an object made just out of vertices which is a spiral, kind of like these:

Here's my code:

def spiral(iterations=2,segs=20):
    verts = []
    faces = []
    z=0
    position = bpy.context.scene.cursor_location
    print(bpy.context.scene.cursor_location)
    deg2rad = math.pi / 180
    gap = 360 / segs
    for i in range(iterations):
        for i in range(0, segs + 1):
            deg = i * gap
            rad = deg * deg2rad
            x, y = math.cos(rad) * 5, math.sin(rad) * 5
            verts.append((x,y))
    for i in range(iterations):
        faces.append((i, i+1))
    mesh = bpy.data.meshes.new("Spiral")
    object = bpy.data.objects.new("Spiral", mesh)

    object.location = bpy.context.scene.cursor_location
    bpy.context.scene.objects.link(object)
    mesh.from_pydata(verts,[],faces)
    mesh.update(calc_edges=True)

But for some reason it returns this in the Terminal:

<Vector (0.0000, 0.0000, 0.0000)>
Error: Array length mismatch (expected 126, got 84)
Traceback (most recent call last):
  File "/Users/jacobgarby/Documents/Blender Things/Blender      Files/python_meshes.blend/Text", line 48, in <module>
  File "/Users/jacobgarby/Documents/Blender Things/Blender   Files/python_meshes.blend/Text", line 45, in spiral
  File "/Users/jacobgarby/Downloads/blender-  2/2.76.app/Contents/MacOS/../Resources/2.76/scripts/modules/bpy_types.py",    line 414, in from_pydata
    self.vertices.foreach_set("co", vertices_flat)
RuntimeError: internal error setting the array
Error: Python script fail, look in the console for now...

Vertices need an x, y and z coordinate.  z was  set to zero and not used. Then there was faces in mesh.from_pydata(...) instead of edges, of which only  a couple were added as you were iterating through iterations.  On top of that you were using i as an iterator in both your inner and outer loop.

To convert between degrees and radians you can use math.degress(rad) or math.radians(deg)

Here is some code I put together a while back to arrange objects into spirals, edited with yours to create a spiral mesh.

Also look into the addon add_curve_extra_objects and in particular add_curve_spirals.py

import bpy
from math import sin, cos, pi
def spiral(segs=30):
    verts = []
    edges = []
    z=0
    n = 3
    position = bpy.context.scene.cursor_location
    print(bpy.context.scene.cursor_location)
    a = 0.5
    for i in range(segs):
        t = n * 2 * pi * (i)/ segs
        # parametric eqn of a helix
        x, y, z = (a * sin(t), a  * cos(t),  a * t / n)

        verts.append((x,y,z))

    for i in range(len(verts) - 1):
        edges.append((i, i+1))
    mesh = bpy.data.meshes.new("Spiral")
    object = bpy.data.objects.new("Spiral", mesh)
    print(verts, edges)
    object.location = bpy.context.scene.cursor_location
    bpy.context.scene.objects.link(object)
    mesh.from_pydata(verts,edges, [])
    mesh.update(calc_edges=True)

spiral()


Object won't smooth shade? I created a scene with some popcorn but am having a weird error where the objects won't smooth shade anymore. Below is a blend file with an example of one of the popcorn kernels:

Blend file:

In Edit Mode CTRLE and click 'Clear Sharp'


How to get rid of double edge I've already applied the mirror modifier and combined all of the meshes together. When I came around to mark seams, I find double the edges on the head mesh only. How do I remove them?

Select all vertices, after that press W > Remove Doubles


Bone moves completely instead of rotating on axis I made this armature watching a newbie video. The upper arm bone was created on its own and not extruded out of the shoulder bone. So now it has no rotation axis like the other bones. Instead of rotating on an axis in pose mode, it just moves the entire bone. I've parented it to the shoulder. Still it does not have an axis at all. This is my first character. So frustrating. Please help. Thank you.enter image description here

In edit mode enable the connected check box as depicted below.


Procedural Rougness texture I'm looking to create a procedural basic rough texture in blender with some texture nodes. Can someone either share a node tree or a link to a video on it? Thanks!

It depends if you mean roughness as a 2D effect or 3D effect.

For 2D roughness you can use a Noise (or this kind of texture) as a factor in a mix between a glossy and a non glossy material:

For 3D roughness you need to plug a Noise (or this kind of texture) into a Bump node that you plug into the Normal sockets of your nodes. Here I've mixed 2 Noise Texture nodes into a MixRGB (try Overlay or Darken or Lighten mode) in order to have some smoother areas.

If you're not fully procedural and use an Image Texture:

In the case of a 2D effect, if you use an Image Texture you can create something without any unwrap, I guess it's the quickest way:

Prepare your dirt texture (a simple black and white jpg is ok).
Create this nodes setup: Texture Coordinate (Object output) > Mapping > Image Texture > ColorRamp > Factor socket of a Mix Shader.
In the Image Texture, load your dirt image, choose Box instead of Flat so that the texture will be projected all around the object. You may need to play with the Blend factor to avoid any seam effect.
In the Mix Shader, plug the 2 materials, the one that is supposed to be the glossy and the rough one.
You can play with the Location and Scale of the Mapping node, but don't play with the Rotation if you want to avoid stretching.

In the case of a 3D effect, same setup on the left, then:

Plug your Image Texture node into the Height socket of a Bump node.
Plug the Bump into the Normal sockets of your Diffuse and Glossy nodes.
Here I've used a (Math) Multiply node instead of a ColorRamp. - Play with the Strength of the Bump to increase the 3D effect.


Difference between Blender 2.8’s camera and world HDRI Does one of you know whats the difference between Camera HDRI and World HDRI

Blender 2.8 now have these options to import Viewport HDRIs

I've noticed that if i import a file (either .hdr, .exr, .png, and .jpg) as "camera HDRI", it only is shown as a Studio Light on Solid Mode

While importing as "world HDRI" it works both in Solid Mode's StudioLight and LookDev (Material) Mode

So...
What's the purpose of have those two ways to import HDRs? Is it a bug, that, being each import mode work only for one Lighting type, make "World HDRI" work for Solid mode too?

edit

This question was also posted on Blender Artists
Got an awesome answer there, and make it clear
Here's the link to the topic: https://blenderartists.org/t/differece-between-blender-2-8s-camera-and-world-hdri/1117783

Well since you seem to have cross posted this I'll just shamelessly plagiarize Brecht's answer for completeness sake.

Camera HDRIs are basic studio lights meant for fast performance with non realistic shading.

They will behave like matcaps in the sense that they are viewpoint dependent and will rotate along with the view angle.

World HDRIs behave as realistic environment maps like the ones you would use in Cycles World environment textures.

They are convenient scene lighting replacement suitable for quickly testing your model and viewing it under different lighting conditions.

Both can be easily easily user customized by adding new entries to the menu either from the user preferences by pressing the small Wrench icon, or by manually adding files to the folder Blender-2.80\2.80\datafiles\studiolights, either under a Camera, Matcap, or World subfolder.

  By Brecht

  Camera HDRIs are like matcaps or solid mode lighting in 2.7x, in that
  they rotate along with the camera. This ensures objects are always
  well lit and you can see their shape clearly, even if it’s not
  realistic.

  World HDRIs are the same as environment textures in the world, with
  light coming from the same global direction. This is the more
  realistic method, and the only one that can be efficiently supported
  for features like Eevee indirect light and light probes. For that
  reason camera HDRI’s are not available in LookDev shading mode.

  Naming of these features could be improved.


Apply scale/rotation - shrinks mesh/rotates mesh 2.8 I'm completely new to Blender and am trying to rig a friends model he created awhile ago. I've got a tiny bit of experience rigging in Maya and 3ds Max and I think that the reason I'm having the issue is because my meshes scale and rotation isn't freezing/applying.

When I imported the model I scaled it up to the right size and rotated it for the same reason.

I've tried applying all transforms to delta, setting origin to 3D cursor and all the various "apply location etc" it just always reverts back to the tiny size and wrong rotation.

What am I missing/doing wrong? please help, thanks. Two screenshots below show before and after applying "apply transforms" NOTE: this is in 2.8 latest version.

Reset Delta transforms to default values before other operations. Then you can move, rotate scale the model in object mode as you want; then press Ctrl A and choose Apply All Transform.


How to remove the watermark in the rendered image? I used Blender cycles to render an image, but the output has a watermark with some words in the top left hand corner.

How can I make it disappear by changing the related setting?

In the properties window, open Render tab, scroll down to Metadata section and disable Stamp Output.


Snapping vertices in a particle system The idea is to snap the four (selected) polar vertices to each other while scaling the particle (meeting snap point, in this case, is the coordinate center). Eventually I'd like to make the sphere radius equal to the length of the tetrahedron edge in such a way to align the vertex grids so that boolean operations can be implemented.
Can it be done this way or is there a better alternative ?

Basically in order to make this

Boolean didn't turn out well in the depicted orientation of the spheres, even though the vertices appeared to be aligning.

With some inspiration from this answered question, though some settings must have been changed because I can't find the other size determining value, he pointed out, I managed to find the right Render>size "0.25" which makes the particles the same size as the original Dupli Object and takes the selected polar vertices to the same spot as I wanted.

and to do the eventual How to convert particles to mesh?
and How to Make Multi User Objects Single User?
is required


Is there a way to solve terminator artifacts? Has anyone found a way to fix the problem?
Increasing the subdivisions the artifacts remains, less visible because the polygons are smaller.
I have also attached Arnold image (Redshift is very similar) even with less subdivisions and more contrast that work better.

From blender 2.90, you can tweak this using the Object's Shadow Terminator Offset Shading property.


Weight Paint adding to wrong side of mesh, subtracting from active bone I'm weight-painting a dog mesh, but the "Add" brush is subtracting from the spot where I click, and instead adding to the corresponding mirrored part on the opposite side of the mesh, over the Y axis. The problem becomes worse as I approach the crease between the selected leg bone and the underbelly, and doesn't seem to be a problem when I am painting the leg itself.

Weight paint was working fine yesterday, and since then I have made edits to the armature and reapplied the "symmetrize" function more than once. I haven't made any changes to the painting options except to make my brush stronger.

This problem was solved by clearing all transformations made in pose mode and then returning to weight paint mode. I don't know what exactly was causing the problem or happening however.


what is the difference between animation nodes and audio nodes I just today found out about animation nodes, which is awesome, but there are some links for audionodes, I don't know whether they are both the same or different.

Animation Nodes Node based visual scripting system designed for motion graphics in Blender.

Audionodes for Audio generation in Blender nodes.


can't read custom property from linked material using python I try to access my materials custom property's value using python. I use the following line of code to do that:

print(bpy.data.materials["MATERIAL NAME"]["CUSTOM PROPERTY NAME"])

what blender returns is this error:

  1.0
  Traceback (most recent call last):
    File "/PATH/TO/MY/SCRIPT/script.py", line XY, in
  KeyError: 'bpy_struct[key]: key "INSTANCING" not found'
  Error: Python script fail, look in the console for now...

as you can see, before blender throws the error it actually logs my property's value. (1.0)

Since I am looping over all my scene's materials I did this to check if the Custom Property is existing:

hasattr(material, "CUSTOM PROPERTY NAME")

For whatever reason this is returning FALSE for all materials.

Does it have something to do with the fact that the materials I am aiming for are a linked from other .blend files maybe?

For me it's a dead end street for now, so any help would be much appreciated!

Unless defined as a bpy.props property hasattr won't work. . Use material.get("prop") or check if "prop" in material.keys()


Set material strength and keyframes in Cycles with Python I am making a piano song animation in cycles where in exact places (if a piano button was hit) the piano string lights up (Emission shader Strength = 5) then fades away (so go back to 0 Strength in 100 frames).

Until now I did this manually. So I checked the frame number where it should be lighten up let's say frame 2345, went back two frames (to 2343) set a keyframe (if this string was hit within 100 frames back its higher than 0) go back to original frame (2345) set the material strength to 5 and keyframe it then go forward a hundred frames (to 2445) set the Emission shader's Strength to 0 and made it keyframe. This is a really time consuming work especially now where there is 3-4 key is hit in the same time...

I need a really simple script to speed things up a little bit. My plan is to do the following workflow. I just check the frame number where the string should lighten up go to that frame in editor, select the string object what is should be lighten up, then hit "Run Script" and the script makes all this for me on the actual frame number on the selected object's material.

I want something like this:

import everything what is needed for this script

curMat = get active object's (what is actually selected in 3d editor) material
curFrame = get the current frame which is shown in the timeline editor

keyframe_insert(curMat.Strength, curFrame-2)

for (curFrame-1 to curFrame+100)
{

check for keyframes in material strength and if there is

delete_keyframes

}

set strength(curMat, value = 5, curFrame)

keyframe_insert(curMat.Strength, curFrame)

set strenght(curMat, value = 0, curFrame+100)

keyframe_insert(curMat.Strength, curFrame+100)

I hope one of you can understand what I want to achieve and help me out with a few lines of code, I would really appreciate your help!

Haven't had time to test this too much, but should work (or be a good start if not):

import bpy

curMat   = bpy.context.object.active_material
curFrame = bpy.context.scene.frame_current

emitStr = curMat.node_tree.nodes['Emission'].inputs[1]

emitStr.keyframe_insert( 'default_value', frame = curFrame - 2 )

# Delete existing keyframes from curFrame -1 to curFrame + 100
fcurves = curMat.node_tree.animation_data.action.fcurves
for fc in fcurves:
    if fc.data_path == 'nodes["Emission"].inputs[1].default_value':
        kfs     = set( [ kf.co[0] for kf in fc.keyframe_points ] )
        kfRange = set( range( curFrame - 1, curFrame + 100 ) )
        kfsInRange = kfs & kfRange # Inresect both sets

        for i in kfsInRange:
            emitStr.keyframe_delete( 'default_value', frame = i )

emitStr.default_value = 5                  # Set strength to 5
emitStr.keyframe_insert( 'default_value' ) # Sets kf in current frame by default

emitStr.default_value = 0
emitStr.keyframe_insert( 'default_value', frame = curFrame + 100 )


Camera does not change it's position I'm having this weird problem with my camera in which I can only render from a certain position that is not the one on the camera. It's like the view got detached from the camera and I can't change it.
I can't manipulate it and it always renders in that position. Deleting the camera makes no difference, and there is no hidden camera in the file.
It's not the first time I've had this problem.

Sorry, I can't upload the file since it is now too big.

----SOLVED-----

What happened is, I somehow put another object as my camera.

I solved it by going on Scene Settings (third tab on the Properties window), one of the first fields asks for the camera (and there I had a plane).

Thanks to eromod for pointing out any object can e a camera in Blender.

You must have set the object as the "active camera".

In Blender even a mesh can be a camera.

There is a bunch of ways to change it but the shortcut is to select the new

camera and Ctrl+ Numpad 0

How can I make a camera the active one?


How does blender calculate the solve error in camera tracking? Just curious, how or what algorithm does blender use to calculate the solve error in camera tracking. A quantitative explanation would be great.

Blender currently uses a KLT-Tracker (Kanade–Lucas–Tomasi) which is documented here.

For the calculation of the solve error the documentation of this implementation might be interesting.


How to display my rendered scene on a new monitor while i am still working on solid mode in my laptop? I have connected my monitor to my laptop and I want the rendered view to be seen in monitor and I want to work on solid mode at the same time.
Is that possible?

Yes it is.

Click on View in the bottom menu of your 3D window and choose Duplicate Area into New Window. Simply drag the new window onto the other screen and switch to rendered view.


Return list of nodes inside material? I am trying to write a script where nodes are spawned and sorted according to where they need to be in the node editor. Thanks to help from other users, I have learned to move the nodes properly. However, the answers they provided used a hard-coded list:

atomicNodes = ['Texture Coordinate', 'Mapping', ...]
imageTextures = ['Image Texture', 'Image Texture.001', 'Image Texture.002']

I have a method of returning a list of nodes that exist in the scene, but they aren't instantiated as a list when I call them:

for i in atomicNodes:
    nodes[i].location.x = locx
    locx += nodes[i].width + 50
    nodes[i].location.y = 0

for i in imageTextures:
    nodes[i].location.y = locy
    locy += nodes[i].height + 200
    nodes[i].location.x = nodes[1].location.x

When I go ahead and just print out the nodes, in the scene using:

bpy.data.materials['Material'].node_tree.nodes

it gives me this in the console:

Using the Python documentation for listing dictionary keys in this format:

nodes = bpy.data.materials['Material'].node_tree.nodes
nodeValues = nodes.values()
nodeKeys = nodes.keys()

then changing the variable atomicNodes to

atomicNodes = nodeKeys

Makes it run correctly.

However, when I try to do the same thing for my list of image textures, I'm having some issues. I get this error when I try to use the filtered list of image nodes instead of the 'nodes' variable:

Here are the scripts on GitHub, I am using the latest release candidate for 2.79 because I am interacting with the principled shader, but I have been having this issue while testing in stable versions of 2.78 too.

Edit: The issue seems to be that while the nodes variable

nodes = bpy.data.materials['Material'].node_tree.nodes

is a dictionary already by default, when I get the Image Texture nodes it is converted to a list, which I obviously can't grab keys from.

When I use my method to collect the Image Textures, it places them into a List already. Unfortunately there is a lot of extra content that I don't need:

[bpy.data...nodes["Image Texture"], bpy.data...nodes["Image Texture.001"], bpy.data...nodes["Image Texture.002"]]

I only want what is inside of the quotation marks of this list, is there any way of doing that aside from regular expressions?

You don't need their names in a list. You can iterate through Material.node_tree.nodes collection which allows to test if the node type is Image Texture and set the position attribute in one go.

Operator example based on Templates > Python > Operator Node:

import bpy

class NodeOperator(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "node.simple_operator"
    bl_label = "Simple Node Operator"

    @classmethod
    def poll(cls, context):
        space = context.space_data
        return space.type == 'NODE_EDITOR'

    def execute(self, context):
        tree = context.space_data.node_tree

        # set the location if node type is
        for n in tree.nodes:
            if n.type == "TEX_IMAGE":
                print (n.location.x)
                n.location.x += 50

        # filter by type
        image_texture_nodes = [n for n in tree.nodes if n.type == "TEX_IMAGE"]

        # get the names
        image_texture_names =  [n.name for n in image_texture_nodes]

        # check the console
        print (image_texture_nodes)
        print (image_texture_names)

        return {'FINISHED'}

def register():
    bpy.utils.register_class(NodeOperator)

def unregister():
    bpy.utils.unregister_class(NodeOperator)

if __name__ == "__main__":
    register()


Resizing specific faces of a 3D mesh I have this column:

But the top and the bottom parts have different size between the curved figure and the final edge of the mesh.

Top

Bottom

How can I adjust this and have equal size at each side?

You can try cutting the model in half, then delete the bottom part. Then use Mirror modifier. Apply it, and if you don't need the cut at the center, just select it by loop select and press X + dissolve. This is, of course, the case when both sides should be similar. It's a column, so I think they should. Let me know if it's not the case - I will update my answer.


Having more than more animation on one rig On this video https://www.youtube.com/watch?v=VyI1zfvUjeM at 0:28 the guy starts to explain that he has 3 different animations as seen on the dopesheet. How can I have the animations cut into 3 different animations?

EDIT: I found a way to do what I want. No more help needed.

Change from dope sheet to action editor and add actions (animations).


GPU Rendering issue “Cuda error at cuCtxCreate: Illegal Address I get that error message when I try to bake a simple AO map in cycles. I can do it with cpu but with the gpu i get that error message.

I have 13gig of memory on the card so it cant be that but just to check I tried to bake on a simple cube and got same error.

Any Ideas?

-Computer-
Processor : 12x Intel(R) Xeon(R) CPU E5-1650 v3 @ 3.50GHz
Memory : 32842MB (5671MB used)
Operating System : Manjaro Linux
Resolution : 1680x1050 pixels
OpenGL Renderer : GeForce GTX TITAN X/PCIe/SSE2
X11 Vendor : (null)

Roll back the Nvidia graphics driver to when it did work properly.

In my case Nvidia drivers to v391.0 caused this error.
Since I don't auto update my drivers I rolled it back to v388.0 and rendered over a 100 frames in full HD with no problems.


Keyframing orthographic camera scale and reproducing it as an action? I have keyframed the scale of the camera in my scene so that it always does kind of a zoom in and zoom out to an object at the beginning of the scene.  Using the logic bricks I have established an "always" sensor with an "action" controller linking that specific action but it isn't working!  I have read this post and tried it but still is not working. Is it even posible to do it in the BGE? I am using v 2.72

Animating the orthographic scale the way you do it is not possible. You can however do this via python using bge.logic.getCurrentScene().objects["Your_Camera"].ortho_scale = your_value. Your_Camera has to be the name of the camera whose orthographic scale you want to adjust. your_value has to be the desired focal length. That can be a float between 0.01 and 4000.0. Following is an example of zooming in to a value of 5.0. Therefore the orthographic scale at the start needs to be above 5.0.
import bge

#getting the camera object called 'Camera'
cam = bge.logic.getCurrentScene().objects["Camera"]

#while the orthografic scale is above 5.0 the script reduces it by 0.5 everytime the script controller is activated
if cam.ortho_scale > 5.0:
    cam.ortho_scale -= 0.5

The script activated every logic tick (always sensor -> true level triggering) looks like this (it has a better frame rate of course). The starting orthographic scale is 23.0:

Now you can write a script that does what you want. Here's another example where we are zooming in first and when this has finished we are zooming out again.
import bge

#getting the camera object called 'Camera'
cam = bge.logic.getCurrentScene().objects["Camera"]

#while the orthografic scale is above 5.0 the script reduces it by 0.5 everytime the script controller is activated, if there's a game property with the name 'zoomed_in' it won't zoom in again
if cam.ortho_scale > 5.0 and not "zoomed_in" in cam:
    cam.ortho_scale -= 0.5
#if the cam is already zoomed in and the ortho_scale at a value of 5.0 the camera is zooming out again, adds the game property 'zoomed_in' to the camera to prevent it from zooming in again
elif cam.ortho_scale < 23.0:
    cam["zoomed_in"] = True
    cam.ortho_scale += 0.5

Here's the result:


BGE Action Actuator and Motion Actuator I'm making a 3D Pacman game using BGE.
I have an action actuator that plays the Pacman mouth animation.
That works, but when I add the Motion Actuator for the player to rotate the character, everything moves fine, except the mouth.
If I remove the action actuator, the whole character rotates, but the mouth is always closed.

Here's the link to the .blend file

I tried looking for similar problems online for about 2 or 3 hours and found nothing.

Thanks in advance

Found an answer that fits my needs.
I made this Python script that stops the action actuator, rotates to the desired position and then plays the animation again.
I also added an always sensor to keep pacman moving on the direction defined by the "direcao" property.

from bge import logic
import math
controller = logic.getCurrentController()
own = controller.owner

name = "AnimaBocaAcao"
start = 1.0
end = 24.0
layer = 0
priority = 1
blendin = 1.0
mode = logic.KX_ACTION_MODE_LOOP
layerWeight = 0.0
ipoFlags = 0
speed = 1.0

sensors = own.sensors

if own["direcao"] == "dir":
    own.applyMovement([0,0.02,0])
elif own["direcao"] == "esq":
    own.applyMovement([0,-0.02,0])
elif own["direcao"] == "cima":
    own.applyMovement([-0.02,0,0])
else:
    own.applyMovement([0.02,0,0])

if sensors["W"].positive:
    currentOrientation = [0, 0, math.radians(90)]
    own.stopAction()
    own["direcao"] = "cima"
if sensors["S"].positive:
    currentOrientation = [0, 0, math.radians(270)]
    own.stopAction()
    own["direcao"] = "baixo"
if sensors["A"].positive:
    currentOrientation = [0, 0, math.radians(180)]
    own.stopAction()
    own["direcao"] = "esq"
if sensors["D"].positive:
    currentOrientation = [0, 0, 0]
    own.stopAction()
    own["direcao"] = "dir"

own.localOrientation = currentOrientation
own.playAction(name, start, end, layer, priority, blendin, mode, layerWeight, ipoFlags, speed)


How to create convincing rain with a particle system How would i go about creating a scene similar to this image. I am especially interested in the how the droplets not only are deflected, but also 'roll off' the subject.

Any advice will be greatly appreciated.

I assume you know how basic particle systems work.
If not i recommend watching a tutorial on basic particle systems (like this one).

Just spawn the particles like you would do normally.

Then add collision to your surface (the creature in the gif from your op) and set the Particle Dampening.

As you can see on the image, some particles are bouncing off, some sliding down the surface.
Hope it helps.


Ghost Keyframes - Missing Keyframes that are still working? Hello Blender Community!
I've been animating this Llama with keyframes and I also added in some wiggle bones to the ears threw and addon. After I baked the wiggle bones for the ears of the Llama. I went on to animate the two characters. Then coming back to the Llama, I noticed there are no keyframes for the Llama except the wiggle bones.
If I don't touch anything the Llama will animate correctly, but if I add in a single keyframe for any bone, ALL the bones stop working and the Llama is left motionless except the wiggle bones and the keyframes I added prior to the baking of the wiggle bones.
Thankfully what I can do as a workaround is to duplicate the Llama and just create a second scene to continue this animation. (The duplicated Llama has the same problem with ghost keyframes)
Is there a way that I can take this Ghost animation and reinsert the keyframes? or somehow get these keyframes back into the rig?
I do not know if the problem is Blender, Wiggle Bones Addon, or my self because I have not found anyone with a similar issue.
Thank you for taking time to read this.
-Pooka

that happens , with me also  ,actually thats not a problem with blender or the ad-don , its with you , you probably are not selection the correct object in your animation  you are selecting an object that doesn't have a key frame there , try selection all things and look if there is something having a key frame there and try deleting it , or you can also make a fresh keyfram there


Can I render each layer with transparent background? My question:

How can I export the PNG file ( like the attachment file ) from blender file?
How can I render each layer with transparent background?

I have a blender file.
https://www.dropbox.com/s/3dfak4v5p8vyuq9/BC%20lending%20page62.blend?dl=0

Answer to 1st question:

**Rendering an image with transparency in **BLENDER INTERNAL****

First you have to tell blender not to render the background, or sky: Under "Render/Shading", switch alpha from "sky" to "transparent". Now only the objects in the scene will be rendered.
You must render to a file format that supports transparency, such as "PNG". Under "Render/Output", switch the file format to "PNG".
Make sure the image channel setting is "RGBA", not "BW" or "RGB". The A in RGBA stands for alpha, where the transparency information is stored in the PNG file.


Baking smoke on headless machine I have a linux vps that has some spare resources left from main activity. I can not get the GUI working, but I was thinking if there is a way to use it for baking with python script.

I see that there is an operator:

bpy.ops.ptcache.bake(bake=True)

But what is the right context for it?

Also if anyone has ideas to get the GUI working under Ubuntu VPS, that would be much appreciated.

Baking smoke is very similar to baking fluid, so I will quote brecht's answer:

  It's a bit more complicated than it could be because fluid simulating baking is only exposed as an operator. That means it expects an active object in the context, which is usually provided by the user interface that is not available in background mode.

However, it is possible to override context manually, see the api docs.

So for a smoke simulation:

import bpy

for scene in bpy.data.scenes:
    for object in scene.objects:
        for modifier in object.modifiers:
            if modifier.type == 'SMOKE':
                if modifier.smoke_type == 'DOMAIN':
                    override = {'scene': scene, 'active_object': object, 'point_cache': modifier.domain_settings.point_cache}
                    bpy.ops.ptcache.bake(override, bake=True)
                    break

This will bake the selected cache for all domain objects in the file.

You can then run this python script in blender with

blender --background /path/to/file.blend --python /path/to/script.py

Or the short way:

blender -b /path/to/file.blend -P /path/to/script.py


Having trouble adding brick texture I have appended an old house building to a scene that was made using blender engine, but now in a cycles scene. I have attempted to add a brick texture to the house but it won't show. I am new to cycles and ideally would like to use the roof texture imbedded in the file but am happy with just adding the brick texture for now. Any help would be appreciated. If it is possible to add the roof texture, I don't know how to add multiple images to separate parts of an object in cycles.

First you haven't assigned your material to your walls, so, in Edit mode, select the walls, then select your brick material in the material list, and click Assign.

Now you still can't see bricks because your current material is not good.

You've plugged your Brick Texture node in the Factor of a Mix Shader, it could work like that but:

It's not the colors that will be taken into account in the Factor of your Mix Shader socket but the values, the more your color will be white the more it will let the bottom node of your mixed nodes prevail, that's why in general we plug only black, white and grey values in this socket. In your case your values are too close, so maybe only use black and white to make it clear and simple.

Beside that, in your Mix Shader sockets, you've plugged 2 Principled BSDF node that have pretty close Base Colors, so it won't allow you to see any brick precisely, maybe choose more distinct reds.

At the end it could give something like that:


AlphaMasked Images showing up with pink instead of texture (Cycles) V 2.78 I'm trying to create a nature scene with some plants which require alpha-masked images for the leaves. But whenever I UV unwrap them, the objects get coloured pink.

Make sure the Cycles Renderer is set as the render engine.

A pink color in texture view means, that there are missing images. You probably moved your Blender file to another directory or changed paths of image textures.

Go into textured mode in the 3D View. In the node editor select the desired image texture node.

If the source path is not found, the message "Can't Load Image" will be displayed. Click on the folder icon to locate your image file (marked green).


For Fluid Simulation, what do the Start, End and Speed settings mean? How do the Start, End and Speed settings work?

Isn't the Speed setting determined by the Start and End settings?

For example, say I have 120 frames (at 30fps, thus 4s), and I set "Start: 0", "End: 8", then the fluid will move around twice as fast as a normal fluid.  But then if I set "Speed: 1", doesn't it contradict the previous settings?

The Start and End values tells the simulator how much "real time" it must calculate within your scene's start and end frames. Note that they are in seconds and not frames, because it should be considered as "real world" timing, included within your animation timing.

The Speed value is like the "motion speed" of the simulation. Lower value will give you "slow-motion" style animation, while higher value will result in a hi-speed animation.

So first you have to take care about how many frames you have in your animation, and the framerate you set in the Render panel, in order to have the corresponding "real world" timing.
Example, as you stated :

start frame: 0
end frame: 120
framerate: 30 fps
real-world timing: 120/30 = 4 seconds

Now you can set your start value as you wish, in order to offset the beginning of the animation, while there is 4 seconds between start and end. (0 → 4, or 1.5 → 5.5, or 6 → 10 for instance).

The speed value, indeed, will allow you to speed up or down the animation. The difference is that the simulation won't take too long to calculate if you  slow down the speed (at, say, 0.1), making possible to keep only 120 frames of animation, on which you can simulate a small moment of the simulation (for example, the moment where the little wave of a drop reach back and separate)

Here you can watch a video by Daniel Kreuter explaining this feature with some examples :
http://www.youtube.com/watch?v=mxG8KbJPNI4
Beware still, at the time of this video, there were no speed value. Instead we were able to tweak the speed with the Real world size property, which is not exactly the same.


Enabling GPU rendering in a background script in 2.79 The structure for setting GPU rendering changed in 2.77 and after a bit of digging I came up with the following code that sets the GPU with the new structure:

bpy.context.scene.cycles.device = 'GPU'
prefs = bpy.context.user_preferences.addons['cycles'].preferences
print(prefs.compute_device_type)

for d in prefs.devices:
    print(d.name)
#2.76-
#bpy.context.user_preferences.system.compute_device_type = 'CUDA'
#bpy.context.user_preferences.system.compute_device = 'CUDA_1'
#2.77+
bpy.context.user_preferences.addons['cycles'].preferences.compute_device_type = 'CUDA'
bpy.context.user_preferences.addons['cycles'].preferences.compute_device = 'CUDA_1'
#bpy.context.user_preferences.system.compute_device = 'CUDA_MULTI_2' # Uncomment for 2 GPUs

It is picking up the GPU cards and it looks like it is setting the compute device correctly but when I look at HTOP the CPUS are being used. Is there anything I am doing incorrectly here or do I need to add additional commands?

In the end this approach worked, the server I was rendering either didn't have cycles enabled or I saved in the blend file to use CPU.