IK rigged elbows have unexpected "laggy" or "jumpy" behaviour when animated To keep this both as short and as informative as I can:

The character I'm animating has bones in his arms set up like this:
The lower arm has a regular IK constraint with a hand controller as a target (chain length 2), and the upper arm has a  regular IK with an elbow controller as a target. Both targets are custom shaped helper bones.

(I didn't use the "pole target" function because it introduces undesired twisting, and doesn't fix this problem anyway)

The problem I have is that the elbow updates in a weird way during animation, as if the IK calculations were struggling to keep up.
When you go to any frame, the elbow first appears in a wrong position. And only after about a third of a second it snaps into correct place by itself.

Sometimes the difference is minimal, other times the elbow faces the other way completely.
Because it takes that short while for the bone to correct itself, mostly the wrong positions show instead of the good ones when the animation is played normally in viewport.

I've made 3 animated actions in total with this same armature, and 2 of them work perfectly fine. Only this one has this problem, which is why I have no idea what the cause could be.
So far I've tried to fix this by restricting bone rotations, re-rigging the arms to use the pole target function, changing position of the elbow targets, disabling animation of the elbow targets, and also baking all of the animation.
None of that has however solved the issue.

If anyone will be able to make any sense of this and tell me what's wrong, I will greatly appreciate it.
The blend file can be downloaded from here:
Blend file on Google Drive

So by messing around I managed to find my own mistake, and hopefully this answer will help others avoid it.

As is the standard with most IK setups, I have 2 bones in the place of the Hand:

The actual deforming Hand bone, which is child of the Lower Arm bone
A helper "Controller" bone, which occupies the same space as the Hand bone, but is not a child of the skeleton.

The Lower arm bone has a regular IK with the hand Contoller as a target, the deforming Hand bone then has a Copy Rotation constraint, so that it always has the same orientation as the hand Controller.

And here's where I made my mistake:

I wanted to add some extra realism to my rig by adding a Copy Rotation constraint on top of the IK to the Lower arm, 0.5 weight and limited to Y, so that the forearm would twist slightly as the hand bone turns. But I've set the target of this constraint to be the deforming Hand bone, and not the Controller bone.
That means the IK solver had to compute a lower arm bone, which rotation was dependent on the hand bone, which rotation was dependent on the controller bone. The rotation of the Lower arm basically had to be calculated in two steps, which is most likely what caused the strange Elbow desync as seen in that gif above.

I've discovered this by the elbows suddenly fixing themselves when I muted the lower arm's copy rotation constraint.

So the solution is following:

As ironical as it is compared to the length of my descriptions, the solution was as simple as changing the target of the Lower arm's Copy Rotation constraint from the Hand bone to the hand Controller bone. That way the rotation for the lower arm is only calculated once, and the problem disappears.


Is it possible to create duplicates of a mesh, that can be deformed and used as blendshape targets? As the title says, is it possible to create duplicates of a mesh, that can be deformed and used as blendshape targets in blender?

like this:

edit:
Here is a nifty little script to deform the base into the target shape...you can save it as a shape key then:

import bpy

target = bpy.context.selected_objects[0]
obj = bpy.context.active_object

for i,vert in enumerate(obj.data.vertices):
    vert.co = target.data.vertices[i].co

But still it would be nice to have them as a live modifier...

I assume you're talking about the blendshapes like these available in Maya (example tutorial: https://www.youtube.com/watch?v=WtfYPxhLO30). If so I'll show you how to do it in Blender on the same example.

Create a mesh, duplicate it 3 times and make some deformations on the duplicates.

Select all the deformed objects and then the base object. Then click on the down arrow in a Shapekeys panel and choose Join as Shapes option.

You have now all the deformed shapes applied to the base model.


Why is Blender so Slow for only one File? I am kind of new to Blender but recently I was working on a monster, just learning how to model, when Blender started lagging unbearably bad, out of the blue. I don't think I changed anything in settings. The file has 43k verts, which doesn't seem like it should be a lot. I have tried restarting Blender multiple tries. I have tried opening the default File and blender works just fine on that file.

Any help would be greatly appreciated.

You have enabled dupliframes, which is set to make 100 duplicates of your model giving your file a total of nearly 4.3 million vertices.

You can find this setting in the object properties under Duplication.


How to fix problems withe textures of imported model? I downloaded a fbx model from cgtrader.com. The model contains textures, but doesn't look good. First problem is that the textures of the head aren't placed correctly. The second problem is that the top can't be textured and only shows a pink color.
Trying to resolve the second problem, in UV mode I opened the image texture, selected the pink areas and replaced the auto generated grid to texture image, but it didn't work.

In render properties change render engine from eevee to cycles.
Create new material, assign this material to pink place and copy nodes from other texture, then change properties for current nodes.


Text getting progressively smaller in the distance I want to extrude text getting smaller in the distance.  How to do this ?  Extrude text property does not seem to permit getting the text smaller.

To edit the text this way you would need to convert it to a mesh.

In Object Mode press Alt-C this brings up the convert popup, select Mesh from Curve/Meta/Surf/Text.

Having the text object converted change to Edit Mode and extrude it manually E and scale S as you want.


How can I instant delete all of the actions ? I need the clean my blend file from the actions, but if I delete them in the dope sheet it doesn't work.

Every animation that is not used by any object and that is not F (fake user, which means that doesn't need to have any user to be saved) won't be saved when you'll close and reopen your file.

Now, to delete an action that is currently used, go in the Dopesheet / Action Editor mode, and press shift and the X on the right of the name of the animation. When you'll reopen the file the animation won't be here anymore.

To delete a F (fake user) animation, disable the F, and same thing: press shift and the X and reopen the file.

If an animation isn't assigned to any object anymore, you can go to the Outliner, select Orphan Data in the dropdown menu, you'll see all the orphan animations, select them all and right click > Delete. Even the F animations will be deleted.

If you only want to delete the visible animations, you can select all your objects, press the Spacebar and type "Remove Animation", You can also go into the Outliner, type "Animation" in the Search box, select all the animations and right click > Clear Animation Data.


Where is the smooth / flat shading property of an object? I know that I can click on the smooth / flat shading buttons in the Tool Shelf panel when I am in object mode.

What I would like to know, is where can I find out if an object has smooth or flat shading on it without having to go and click the buttons to see the difference?

The smooth/flat shading option is only applied per face and not per object. So there isn't a way of viewing the shading status of an object.

When you click 'Smooth' or 'Flat' shading while in object mode you are simply telling blender to smooth each individual face. You could go into edit mode and set smooth or flat shading on a selection of faces instead of the whole object, meaning: the object would have both smooth and flat shading.

You could create a python script which loops through the faces of an object and sees whether the majority are smooth or flat shaded by accessing the use_smooth property of a polygon (face) and seeing whether it is True or False.

You can access the use_smooth property via Mesh.polygons on a given object:

# test the first polygon of a certain mesh
>>> bpy.data.objects['ObjectName'].data.polygons[0].use_smooth
>>> True

# set the shading of all polygons to flat
for poly in bpy.context.object.data.polygons:
    poly.use_smooth = False


How to make a bubble that doesn't reflect the inside I've created a bubble and inside of it, I have a little character. The thing is that the bubble naturally reflects what's on the inside as well, so when you see the final render, you can see the mouth, ears, eyes, etc of the character reflected on the bubble.
It is possible to disable the reflections on the inside of a bubble/thin glass?

I have no solution for a glass material. Changing normals of the inside wall of glass or using a different material for the inside of the glass results in problems with refraction etc.
Instead you might try to change the material of the object inside the glass bubble. I've put an Emssion Shader on Suzanne so that the reflection is clearly visible. If I mix the Emission (or any other) Shader with a completely white Transparent BSDF and use Glossy Depth from the Light Path input as a mix factor, then the reflection only shows the transparent material i.e. nothing.

Of course that's not very handy if you try to put objects with many different materials into the bubble because you cannot simply have one glass material with the correct settings, but many other materials to prepare.


How to smooth my Topology I managed to cut a hole in my mesh without adding extra verts but now I have a problem with the smoothing. It doesn't smooth the edges around the whole as you can see. How can i fix this?

One way would be to change the direction of the edge flow so there is a loop around the "hole". You can do this by selecting the corner vertices (in pairs) and merging them at the center.

You can then add an edge loop around the hole and pull it in to define the top of the edge.

If you want the inside of the hole to look "cleaner", add an edge loop in the center, and bevel it until the top and bottom edges are close to their counterparts in the hole. You might also want to select the bottom faces and inset them very slightly.

Final result is a clean cutout:


copy from active to others: selection? I continue to play with the Wrecking Ball tutorial, and am now trying to impose some materials on the huge stack of cubes.  Obviously I should have done this in the beginning, before the first cube was array-duplicated and so on, but here I am with the stack all built, trying to colour them retroactively.  I separated one cube, applied a couple of Materials (darker brown for the sides, lighter brown for top and bottom), and now I would like to xerox those colours onto all the other cubes.

So.  Deselect the template cube, select the whole stack, then re-select the template cube last so that it is Active.  Then use the Special menu in Materials pane to Copy from Active to Others.  But this copies only the primary material, not the contrasting secondary material.  All the cubes are now solid dark brown, whereas I was hoping they would have light brown tops and bottoms.

Is there any way to copy Selection from Active to Others, as in "I have selected the top and bottom faces of this cube, and I want all the other cubes in the stack to have their top and bottom faces selected also, so I can Assign the contrasting colour to them"?  Or is this just a dead-end, and should I delete the lot and start over with a correctly-coloured cube as my master object for creating the stack?  I don't mind the practise in Array modifiers, but I would think that xeroxing a selection pattern from one to many identical objects might actually be useful... so am curious to know if it is do-able.

Select all the objects you want to copy a set of materials to, and then shift select object with the finished material.  Press ctrl+l, and choose to link "Object Data".  This will link everything including all the materials and the shape of the object.


How would you unwrap 'football' like shape to have a world map as a texture? Pretty straight forward question, I am not sure about the answer though. I have attached the screenshot of a 'football'like shape that i'd like to unwrap and use world map as a texture on it. Any ideas?

Thank you for your help,
Waqas

Download Blend File

If by "World Map", you mean an equirectangular image, you don't have to unwrap it at all. Just use an Environment Texture node instead of an Image Texture node and plug the Object coordinates into the Vector input. Node setup and result:

And .blend file:


2.82 signed with unknown CA? Why is the new 2.82 signed with a cert that is not recognized by Windows? Is this typical?

I don't typically install exes with invalid or unrecognized certs.

Thanks,
Mike

No need to worry, everything is fine.
Main Reason
Since Blender 2.8, the installer is signed by the Blender foundation for improved security. However:

Ray Molenkamp (Blender for Windows developer):
Windows Smart Screen is throwing a fit, since we are a new publisher it has never seen before.
There is nothing we can do on our side about smartscreen except wait for it to have enough data to trust us.

Temporary solution
(versions that don't trigger Windows Smart Screen)
Blender from Microsoft Store
Blender from Steam
There's a whole thread on developer.blender.org if you want to know more.


Array of planes with different static textures I'm designing and rendering a deck of cards. Right now, I have a fan that looks like this:
[removed]

So my main goal is to do the same thing, but have it show the individual faces of the cards. I have tried using the "Generated" option under the texture mapping options on a single image with all the textures side by side. I tweaked the offset and size to make it fit perfectly, but it only works if the X offset of the array is equal to 1:
[removed]

If you change it, it looks like this: [removed]

So to summarize, I want to have each card have a separate texture that does not change depending on position/offset/rotation/etc, while still maintaining the functionality of the Array modifier. How can I do this?

(By the way, I am using the internal renderer)

I've had some luck with this approach.

UV map an array of card geometry against whatever batch-of-cards image you are using. (I imported the image as a plane for reference, adjusted a card-array so the geometry captured the individual cards, and projected the UV from an orthogonal view)
Apply the array, and P separate the card-array-object by loose parts. You should now have a set of separate card-objects, each with its own UV coordinate reference to the batch image. (So now, they will use the 'UV' texture space in their common front-face material)
With all the card-objects selected, ShiftAltO set their origins to their geometry.
Make a Group of the cards
Make an array of small square Planes, Object-Offset as you choose
Use the plane-array as an emitter for a particle system, with the card-group as source of instances: the settings something like as shown.. (all other settings null, no physics, velocity, etc.)

This isn't without minor gotchas.. sometimes the rotations can flip out (gimbal lock?) so watch out for that before committing to a major render.

Hopefully you will retain all the features of array manipulation on the array of plane emitters, and the individual cards will follow. If you 'Use Count' in the particle Render settings, you can select and order the cards in the array.

It's sensible to parent the plane-array and the offset-object to anther empty, so you can transform the whole arrangement with it, without upsetting the array's offset.


Limit driver amount to only a certain part of a rotation I am making corrective shapekeys for a character's knee. I have created the shapekey and now need to setup the driver. So far I have followed this tutorial: https://www.youtube.com/watch?v=f3JWNIkwBZ8

I currently have a variable of the shin bone's local X rotation, with a type of Averaged Value. The current behavior is that as i rotate the bone, the driver value hits 1 at ~65 degrees of rotation, and then goes back to 0 as rotation continues. This means that my corrective shape key kicks in far too early, and then shuts off by the time it should be coming on.

I want the shapekey to start coming in at 90degrees and be at the full value of 1 by 135degrees. How do I achieve this?

Rotations in blender are natively in radians.  To linearly map 90 to 135 degrees to 0 and 1 we can use

 (r - radians(90)) / radians(45)

will give us 0 when r = radians(90) and 1 when r = radians(135).

To be sure the end points are taken care of, (The shape key min max should do this too) and the driver expression returns 0 for angles less than 90 and 1 for angles greater than 135.

 min(max(0, (r - radians(90)) / radians(45)), 1)


Animation Nodes: Simple Grid Mesh not working What's wrong with the following nodes setup? Why doesn't it create copies of Suzane?

You need to extract the number of instances from the vertex list:

There is only 1 grid mesh, so it feeds just single instance.


Random scale and rotation within range and in circular shape (tree leaves) I'm doing some leaves meshes in ver 2.82 and want to know if there is a way to apply a scaling and rotation within a limited range so I won't have to do it on every leaves. I want to create some tuft just like this picture:

I'm trying to create a game with graphics in that style and want to keep it simple with low polygons.

I tried with particle system, but it not ended well lol. I really need more practices with this feature...

Maybe a ball with some leaf particles that use gravity so we can see the upper part of the leaves just like the pictures.

Your question lack precisions, but here is a try:

Create your leaf object, here I've used a PNG picture with a transparent background. The following setup is very basic: it would need a bit of glossiness and translucency, and maybe random colors variations:

Create the emitter. Here, to stick to the way the leaves emit, I've created a series of cylinders and cones:

Give your object a Particle System. Choose Hair, enable Advanced, in Emission choose the Number of leaves you want to emit, enable Rotation, in Render choose Render As > Object, disable the Show Emitter option, and in Instance Object choose the leaf. Tweak with the various Rotation and Scale values.

Your bush of leaves should show:


Black area on my 3d model. How would I fix this? I'm trying to model a coffee cup and then when I connected the grip to the main cup this happened.

Select all your Faces and press  Ctrl  +  N  (Recalculate Normals)

These faces face the wrong direction, in fact they point towards the inside of the grip. This sometimes happens when you manually conect faces but it's no problem at all.

In case this doesn't work and some faces still point to the inside you can select those manualy and press  Ctrl +  F , then select "Flip Normals".


Why Blender doesn't let me select all aligned vertex edges at all? I drew three coloured squares over the screenshot, so you can catch easier what do I want to accomplish here.

I want to select the 4 edges of the vertex as stated in the green square and not only 2 as shown in the red ones.

I don't know why Blender doesn't allow me to select them. For unknown reasons sometimes I have to start all over again, all because of this.

Where you have a vertex selected inside the red square, the highlighted edges are the ones connected to the selected vertex. The other edges don't appear selected as there is a second vertex that appears to be in the same position as the one you have selected. If you move the selected vertex you will find it moves away from the other one.

The easiest solution is to select all vertices and Remove Doubles. If that doesn't merge anything you can press F6 and increase the merge distance. Don't go too high or you can merge the entire mesh.

Another option is to select the nearby vertices and manually merge them together with AltM

When you get vertices close together you may find it easier to switch to wireframe display to select the vertices.


How to add new bone to existing rig? I have rigged model and want to add some new bones to it. But when I add them, they do not affect the mesh, unlike the rest of the bones, which they are children of. How do I make the new bones affect the mesh too?

This forum already has similar topics, but there are no answers in them.

So let say you've parented your mesh to the armature, With Automatic Weight for example, and that you've created a new bone called arm_L.

Select the part of the mesh that this bone is supposed to affect, go in the Properties panel > Object Data > Vertex Groups, create a new group called arm_L and click on the Assign button to assign these vertices to this group. If the group has the exact same name as the bone, the bone will automatically influence this vertex group.

Note that on the right of the vertex groups list you have additional functions.

Another method is the Weight Painting, you can't always count on it though.


How can I make stationary lava with the fluid simulation in blender? I am wondering how to make stationary lava with a fluid simulation in blender.  I don't want it to be an object I want it to be fluid.  And I also don't want it to be filling up as the animation starts.

You can setup a fluid sim and start simulating some fluid, as the simulation is baking you can progress through the timeline to see each frame as it is created.

Once you get to a frame you like the look of, you can cancel the bake. Under the modifiers properties of the domain object you will find a Fluidsim modifier, by clicking apply you will remove the simulation and leave the domain object permanently shaped as you see it, as a piece of water frozen in time.


Boolean Modifier Mesh Geometry I'm trying to make a shower drain and am using a Boolean modifier into a very flat cylinder. I was able to get the circles where I wanted them, but the geometry is weird. When I add a subdivision surface modifier, it gets all messed up. I've been trying to dissolve edges, and re-mesh but I just can't figure out what to do now. And frankly, I don't really understand the root of this problem. Any thoughts?

Thanks!

The extrusions inside a flat surface should be inset, otherwise blender is trying to smoothen the sharp edge between the surface and the hole resulting in a weird geometry.


Liquid simulation sees obstacles' rotation correctly but not their location I'm having a problem with a simulation, where an obstacle and an outflow are being moved by a parenting relation to an empty, and some fluid should be interacting with them.

The obstacle is a glass-shaped one and should retain the liquid within itself.

However, this happens:

(re-baked at very low resolution, but it happens exactly the same with 280 subdivisions)

It looks like the rotations are followed correctly, but not the locations.

Any idea how to make the simulation engine see the actual position/rotation of the obstacles?

Edit: I've made a minimal working file with my issue. It's particularly frustrating: I've recreated every single piece of the simulation but to no luck! It looks like that file is compromised but I can't understand why!

(It requires baking, but it should take only a few seconds on most computers)

Curious about the problem, I set it up myself, but a bit simpler.
The cause is that your glass is too thin walled. Upon closer inspection I saw that at the start it already slips through the bottom.

So I created a thick cup for the water and then you see it stays contained. Because you wouldn't like to create such thick glass, what you could do is create a helper object that has the same inner dimension as your glass, but with thicker walls. In the outliner you disable the render output for this object (so that it won't render), but it will contribute to the backing of your fluid.

*) notice that it's not the best GIF, as I am kind of new to creating GIFs.

update 1
Ok usually the above is the case with fluids, but in this file more was going on. Some of the objects had non applied scales (ctrl+a) all objects where parrented to a bezier. I removed it and it behaved right. Though then ofcourse the cup wasnt moving. At least it showed your walls where thick enough. So i went to frame 0 and in 3d view while selecting the cup press i Select "loc rot" skip a few frames (best do this in Right or left View), then move cup up , rotate slightly over x axis (R+x) skip some frames again move cup towards the bin rotate some more. press i loc rot again.
So with "i" +locrot you split up the movement in parts, and you can even control how smooth the motion goes between each "i"+locrot in the graph editor where one can adjust for smooth movements.
Here is the fixed version :

Update two
There is another way to fix your blend file, but the result wont be as good as compared to update 1, you'll have to apply scales to your objects first.
Next for the cup under volume initialization there is an option "export animated mesh", the solver works a bit different (and its not looking as good as update 1), its rarely used. Often used when combined with armatured meshes, i'm not sure why you had this small bezier cube, for such simple motions i wouldnt use bezier curves but go for update one. Just compare how few i+locrot i had to do as compared to the many nodes in grapheditor for your object (that might be a close match to something your not showing here, but tuning that many key frames isnt handy).

update 1 in action :


Rendered image is just grey I am having some issues when rendering an image, my rendering screen is turning into grey even when making a full render. What am I doing wrong?

You have the focus of the camera set to 0  and are using a lens aperture of 1.0. Basically your scene is so out of focus that you only see gray. Change the distance value to the actual distance form the camera to your object, and maybe try a higher number for the f-stop.

To find where your camera is focusing you can enable display->Limits. If you move the focus you'll see a cross mark that indicates where the focus point is:

A trick you can do is use an empty. Move the empty to the place you want the camera to focus on and select the empty (or any other object as the focus target).


Ctrl + Alt + Num 0 Doesn't work I've followed the doughnut blender tutorial on youtube step by step, but when it comes to rendering, Ctrl + Alt + Numpad 0 doesn't do anything.
I'm not sure if I changed something by accident, but even doing it manually doesn't work. I've looked up the problem and haven't found anything similar. I don't know what else to do, this is the first time I'm working with Blender.

If you want to add this feature to Quick Favorites you can follow these steps:

Press F3 to search for commands and type "active camera"
Right-click RMB on Align active Camera to View and select Add to Quick Favorites
Press Q to get the list of favorite commands and you can quickly select the Align Command from that list

Otherwise you can also follow these steps to quickly enable lock of the camera view:
Step 1
Press N in the 3d View to open up the right sidebar and go to View:

Step 2
Right-click RMB on Camera to view and Select Add to Quick Favorites:

Now you can enable Camera to View by pressing Q:


How can I copy one side of a rig to the other? I need to mirror the half part of the rigging of my character, I remember it was something with the scale or rotation.. does anyone know which was the right solution step-to-step?

In order to mirror a rig down the very middle, you'll need the 3d cursor reset (ShiftC) and used as your 'Pivot Point' (.). That'll determine the mirror center, so long as the rig itself is placed correctly in the center (0,0,0). Now Select any half of the armature (excluding the spine/middle) and duplicate it with ShiftD, next press CtrlM + (the axis you are working along, usually  X) to mirror it over to the other side. With the selection still instact, press W > Flip Names to update the names so something like upper-arm.L becomes upper-arm.R.

After doing this, the mirrored bones might have a different roll from the other side. To fix, select the original bones (can just invert selection with CtrlI if you still have the mirrored side selected), enable X-Axis mirror under Armature Options in the toolshelf and press CtrlR to fix the roll.


How to achieve anime-like smears in blender? So I'm trying to do an anime-styled animation. I want to do something like a smear over the character when they move really quickly. Something like this:

Is there any way to achieve something like this in blender?

Edit: I've just tried something that kinda gets the effect I'm looking for. I took a plane and gave it a glass bsdf and then a noise texture, connected that up to a mapping node, and then altered the scale to give it this stretched look. I then put the glass in front of the model. Having the plane would help me animate this effect. The problem is that it affects the background as well. I'm wondering if there is a way to isolate this effect to just the model.

In node editor:
You could try using the displace node which moves each pixel according to an input rgb, where red is how much the pixels will move in the x direction, and green is how much pixels will move in the y direction.

(I didn't change any settings for the cloud texture, I just use the default values)

Edit:

In 3d editor:
If you want to do it directly on a 3d model in the 3d view, you can use the displace modifier.

create a cloud texture and make the size very small.
Then add the first sub-surf modifier if your model don't have enough geometry.
Then add the displace modifier under, and change the direction to only 1 direction (X, Y or Z)
Then add 1 more sub-surf modifier to smooth things out.


How to configure Blender for 2D functions only? I'm trying to convince a colleague of mine to switch from AutoCAD LT to Blender for structural drafting purposes. Even though Blender was not originally designed for 2D operation, it has the advantages of A: being free (as opposed to $1000+) and, B: having a lot of potentially time-saving functionality (the loop-cut operation alone could probably cut 5% off of drafting time, not to mention the array/mirror modifiers, etc).

However, my friend does not need most of Blender's 3D functionality, since structural drafting is almost exclusively done in 2D. In the best case scenario, I could configure him a stripped-down copy of Blender with all the exclusively 3D operations and hotkeys hidden, as well as rendering/materials/physics/etc. At the very least, I would like to configure Blender so that it is locked into orthographic top-view. How would I go about accomplishing either of these?

You want to setup the layout the way you want and save it as his startup.blend.

By adjusting his preferences you can delete entries for changing orthographic/perspective, view front/top/right. As you probably know the shortcuts you want to disable you can search for the inputs by key-binding.

The far extreme is to compile a custom build for him, with this you can also remove menu entries for changing the view orthographic/perspective and even hide the window types menu so he can't accidentally change the 3dview to something else.

Or you can just teach him to use what he needs, and say just ignore all the other stuff that you don't need to use. I'm sure he can handle exploring other parts of blender if he feels adventurous and knows you to call when he gets lost.


how to create realistic/physically accurate sand blowing over dunes animation? This question addresses exactly what I want but it hasnt been answered: How could I create a sand dune animation?

In case it might be helpful I found this paper on the physics of it (although uncertain if its the same thing as in the above desired image): https://arxiv.org/pdf/1201.4353.pdf
Dunes at pg 39.

Something can be done with Smoke simulation, partly used to fake soft dust and partly to be used as a Force Field > Fluid Flow for Particle system (sand particles).

Issue
The main issue with smoke sim is you can't expect backflip turbulences behind the tip of dune.

Note: to see smoke like this enable
Simulation Properties > Fluid > Viewport Display > Slice and Grid Display ... just move White slider to the left side of Colorramp to make it brighter.

version Smoke
I'm not going to do step by step answer since I don't know if this is a way for you. Just a quick overview ... One Landscape object is used to be rendered and also be Fluid > Effector for simulation (to let smoke flow over). Second Landscape (copy of first one) is used as Inflow object (emitter of smoke).
To build sim quicker ... with this object selected search for Quick Smoke. This operator automatically assign this object to be in sim Inflow object and creates also Domain with Smoke (volumetric) material.
The only one parametr I changed (probably :)) for Domain setting is Gass > Heat to zero (or something low) so smoke is not raising up, but stay on ground level.
Because we don't want to emit smoke from all surface, switch to Weight Paint mode and paint by Strength 1 (red) places you want to emit smoke. This creates a Vertex Group. Use this Group in Simulation Properties > Fluid > Settings > Vertex Group (usually named "Group".
Last thing ... add Force Field object type Wind here Strength 150, but probably can be less ... play with the value.

But if you need only to let fly some "dust" from dune edge, you can probably fake it by creating a Vertex Group only from top edge vertices and use them as smoke Inflow.
Enable for Domain under Physics Properties > Fluid > Dissolve for effect from your reference image.


How do I prevent cloth from exploding and growing continuously? (Blender 2.91) I am having a hard time attaching a cape to my character. For some reason, when I press play, it continuously expands the mesh. I messed with the collision settings and tried applying all transforms to the mesh. What I am doing wrong?
Here are reference pictures:

In order to make it work I switched the order of the modifiers in the modifiers tab, and put the empty modifier, which I used to attack the mesh to my object, on top and the cloth modifier on the bottom. I also used subdivisions rather than using loop cuts on my mesh.


Is there a possibility to move multiple objects to a deferred origin, but maintaining the space between them? Using "set Geometry to Origin" doesn't do the last thing. I have a landscape and when i do this all the objects are moved to the origin, but e.g. the flowers or trees are in a completely different position (in the terrain).

Below are detailed instructions on how to shift multiple objects as if they were one. I am using a house models that is made up of separate models.

Go to Select Menu
Select All by Type
Select Mesh

Press Shift + Ctrl + Alt + C then “Origin to Geometry”

Press Shift + S select “Cursor to center”

Press Shift + S select “Selection to Cursor (offset)”


Add a transparent image on top of a material I'm designing this animal-type creature, and want to add a transparent .png image to its face with the face features (object has a subsurf).
On the left is the image with the features, on the right is the part of the object where I want it to be.

I tried to import the image as a plane, but matching the shape of the plane with the face didn't work, and the lines of the face left shadows on the head, and could be seen as a different object from some angles (although it's the closest I've gotten yet). It looked like this:

So , I tried selecting the faces of the head that the features should go over, and create a new material for it. Unfortunately, since the .png is transparent, the result produced was this:

(where it's impossible to tell the transparency from a black background default color, and where I wouldn't know where to start to adjust size and position).

I also tried UV mapping, but then the whole object became black with the features repeated all over.

Is it something I have to go into Nodes for? I'm kind of stuck here. Creating a new material and applying it is simple, but applying a material that is an image is a bit more complex it seems... Ideally, I would reproduce the same technique for the adhesive bandage on its arm (seen on the right of image 1).

Don't think in terms of transparency but in terms of masks

Most of the confusion comes from the idea that, if there is "transparency" in the image, there has to be a node for transparency involved, and somehow the alpha information has to be connected to it.

Please read further.

The basic workflow:

1. Determine what part of the object will use the texture.

In Edit Mode select the faces where you want the image to be mapped.

UV coordinates are used to map the image texture precisely on the object.

Press U to Unwrap them (depending on the shape you might need different a projection, in this example I used "sphere projection" but for your mesh it might be different, this is not a post on UV mapping).

2. Create the material(s) and use the image to control the mix of different parameters.

Create a new material and assign it to your object.

To edit the material, open the Node Editor window in shader and object mode.

For blender 2.8 use the shader editor.

Before you do anything else: let's go back the key concept:
There is nothing "transparent" in an image.

An image with an alpha channel, is composed of two different elements. The RGB (Red, Green and Blue channels, or color information), and a black and white channel called "Alpha" channel. White parts determine what is opaque, and black areas what most people call "transparent".

All of this is easier to understand if you don't think at all in terms of transparency and think in terms of Masks, and use those masks to control how elements mix.

The alpha channel of a given image can be used as a Mask, to control the mix of color or the mix of shaders

White areas will be one element of the mix, Black areas will be the other, and any shade of gray will be a partial mix.

1: To control the color of a shader.

If you want to use the color information of the image over the color of a given shader, in a way that all other properties of the shader are homogeneous, then use a color mix node, and have the mask be the factor for the color of the shader. Plug Alpha to the Fac of the mixRGB and the resulting mix to the shader's color input.

Pay special attention to the order in which the sockets are connected.

The black areas of the mask(or "alpha" channel) will use the color set in the RGB mix node, and the white parts will use the color of the image used as texture.

If you are using more than one texture, then use both inputs of the color mix node to mix the textures.

2: To control the the mix of different shaders.

Use this setup if you want to use the mask to control the mix between two different shaders. Note that doing this will make the masked areas have different characteristics.

The mask (alpha) on the image will to control how a shader that uses the colors of your image texture combines with another shader.

Let's see how to deal with transparency then.

Adding an image on a glass object

Glass is not different than any other shader.

If the color image is intended to be part of the glass shader, then use a mix color node. The image's color will be part of the shader's color only in the areas determined by the image mask.

If the image is supposed to be opaque, or  be a completely different material, then the alpha mask should control the mix of two different shaders.

And now for

Real transparency:

If the image's mask is used to combine a transparent shader with any other shader, then you can see right through the mesh.

Or the transparency can take the color of the image:

What about the Principled BSDF shader?

It is the same as any other shader. Use the mask to combine colors, shaders or any of the other qualities.

In newer versions of blender the Principled shader has an input for Alpha. If you plug in the alpha channel of the image directly to the alpha input of the shader, you will get a fully transparent object, except in the areas controlled by the alpha channel. In this case you don't need an additional transparent shader.

And, just for fun, you can use the alpha mask in as many combinations as you can think of.

For multiple images with alpha channel overlaid on top of each other:

When working with shaders remember that, RGB information and Masks(based on alpha channels) follow separate paths.

So let's break this in two parts.
RGB

First Combine the RGB information using the alpha channel of the image being overlaid as a mask (fac) to control mix over the background image.

Alpha

Then you can use the sum of all of the alpha channels as a mask to control the mix of color or shaders. You can use a Convert>Math node and set it to add mode.

To mix the colors for a shader color:

For a mix with other shaders:


Each camera may always keep the same resolution? I have an object with different cameras that these have different resolutions, but every time I make a render, the camera has changed the resolution of the previous camera, is it possible that this does not change the resolution?

thanks

As far as I know, the answer is no.

The resolution is a global property used by all camera objects in the scene.

One way to work around this is to create a new scene:

Create a new scene with Link Objects in Info > Header by pressing the + button:

This will make copy the current scene into new one and make object mesh data and transforms linked from one scene to another, so if you move or edit an object in one scene, the corresponding object in another scene will move to match it.
Set the other camera as active in the new scene (CtrlNumpad 0)
Change the resolution in the new scene.
To render, select the scene which has the active camera and resolution you want and press F12

Note that it is probably simpler and easier to set the resolution manually when you render.


How can I apply textures in Blenders UV Editor so I guess I have a really basic question here. I wanted to apply a texture to my mesh trough the UV Editor. I opened a new Image but here comes the first problem already.
I can't move/ scale the image.

I need multiple textures on the same spot (Specular, Diffuse, Normal). Once for the front side and once for the back side.
Do I have to do that in photoshop or is there a way to move images around in the Blender UV Editor? When I am looking for tutorials I only find how they export the UV out and edit it in a seperate software.

You may try using a Stencil mapping option. In UV Editor set the mode to Paint. Add two textures in a Texture panel using the '+' button. Change the brush mapping type to Stencil.

Your texture stencil should appear. Press Image Aspect button to get the original picture dimensions. Hold Ctrl+RMB to rotate stencil, Shift+RMB to change its size and RMB to pan it. Then paint.

Click on the texture preview window, choose your second texture (Up/Down Arrow, Enter or choose it from the textures list) and paint again.

You can use the same method in a 3D View window. It's very useful for blending/hiding the seams btw.


Texturing a gas giant / moving noise context

For practice with noise in blender I would like to create a scene as similar as I can to the one found in this video. The hardest part is to create a texture similar to the one displayed on the planet. I would like some help trying to derive how the texture is built up.

As a start I found this tutorial that shows similar textures being made by the use of noise, but the results are much simpler. I was wondering if the noise textures used in this video could be combined one texture.

My first question is wether this texture could have been generated using noise or if it has been made using an a fluid simulation (or both). The flow of the texture on lower levels looks very realistic, altough the higher levels of the texture look generated using noise.

Texture layers

The finest details of the texture seem to me like the combination of musgrave noise with very small scaled wave noise at its input, but more 'feathery', like the musgrave noise combined with white noise. Is there any combination of these two types of noise that result in a similar pattern?

This generated noise seems to be stretched out and compressed by a moving fluid-like animation. If the lines of the wave noise get closer, the detail between them and they combine into a feathery blur. I have no Idea how I would accomplish a similar effect in blender. Any help with this would be appreciated.

On top of all layers there seems to be a moving combination of musgrave noise and wave noise as a "filter" to change the colour (gradient) of the lower noise on a larger scale. The wave noise seems to have a large scale and the filter must have very gentle colour gradient.

Well formulated questions

Could a similar texture be created using just noise generation from blender?

How do I combine the types of noise as shown in the tutorial into the "feathery waves"?

How could I achieve a similar flowing movement in the noise?

Did I miss any effects from the video in my layer breakdown?

Texture coordinates are an array of three values for X,Y and Z.

Colour is an array of three (or four with alpha) values for R,G and B.

While we are taught to only connect matching sockets in a node tree, some differing sockets are interchangeable, colour and vector are one of these interchangeable types.

What this means is that we can connect a noise texture and texture coordinates into a mixRGB node and then connect that to the vector input of another node. This distorts the texture coordinates in a way that can give results like what you are after. You can then add another mixRGB to combine a second texture, and third...

The SpaceVFX tutorial explains this in more detail, including using it to also make solid planets by defining water and land then add some mountains and rivers to the land.


UV unwrap or geometry issue (cylindrical object) I have created a mason jar object, and I am primarily having issues unwrapping the lid part of the mesh:

When attempting to unwrap properly and avoid an overhead projection type mythology that requires placing the rings in a separate location in the UV space, I am not sure how to reconcile the result of the unwrap.

I want to avoid a lengthy manual process of manually moving around vertices in the UV space to achieve a good result.

Using the unwrap methodology above yields seams when brought into Substance Painter and having materials applied.

I am also trying to unwrap the entire object onto one UV image and even at 2k, the results seem fairly low resolution.  I have made sure transformations were applied to the object prior to unwrap, so the relative size of different parts of the UV shouldn't be the issue.

My goal is to have a fairly clean unwrap that allows for as few seams as possible and a maximize usage of the UV space in a 2k image.

Is there a better way to mark the seams?

Is my overall geometry unsound for efficient UV unwrapping and maximizing use of space?

Also, the interior faces may be important as I plan on applying alpha transparency to the materials applied to the lid and jar of the object.

I have attached the blend file if anybody was interested in taking a look and pointing me in the right direction.

I plan to use the model in the Unity environment.

Thanks!

The lid probably only needs a single UV seam on its lower inside edge.

Then you can arrange the UV's something like in the screenshot below:

Your jar was almost 2 meters tall. Unless you have a special reason not to I would suggest that you always model to real world dimensions. In this casxe scaling it down to size ( s 0.1  giving a more realistic jar hight of 180mm) means you get 10 times the texel density on the finished model when using the same size texture.
(2K texture for such a model seems a bit excessive :) )

Also, you have way to many edge loops in the Wires. I would suggest removing as many as 4 out of 5 in the Low version.


The transforms of appended objects change during rendering I have these teeth objects in a separate blender file that I plan to append to other files when I need them (I append them as "objects" because when I append the mesh they don't seem to show up), but the two times I've tried, the rotation, location, and scale are strange on import, and on render.

Also, something to note is that the size and rotation of the teeth while working is after resetting the rotation and scale with alt-r and alt-s
another thing to add is that the position of the teeth in this project is the same as how they are in their original file. The numbers involved in their starting/rendered position seem random

After looking through all the details of my project I realized that the teeth objects had one keyframe on a later frame for some reason, and I was editing their transforms on a different frame so the transforms weren't actually applied.


Why is Blender's default cube 2 cubic meters instead of 1? I had a very frustrating experience with Blender's UI. In the transform section there is location, rotation and scale and I thought scale would be dimensions, which I found out later it is not. Now I think a lot of people will confuse scale with dimensions (which is not even visible by default). Let's say I want to make a 0.1m cube; I tried to set the scale to 0.1 but since the default cube is 2m my new cube is now 0.2m.

Why is the default cube chosen like this and not the more natural and intuitive 1m3?

Wouldn't a default cube of 1m3 be better since then a naive user who confuses scale with dimensions would still get the desired result when trying to input a cube of length 0.1 and input that number into the scale?

There is no reason. But the default cube goes 1 unit in every direction, it's the same size as a sphere with a radius of 1 unit as well as for example procedural spherical gradient, a plain axis empty has lines going 1 unit in each direction of all axis as well. If it was 1 unit size and it was centered it would have sides ending at half a unit in all directions, that might be weird. So for what it's worth, it has some sense behind it. I think it is mainly this way, only because it had to be some size, and this is no better or worse than anything else. You can create a cube of any size and hit ctrl+u to save another default file if that makes more sense to you.


Big Screenshot of Node-Tree Would it be possible to screen capture or output node-tree network like really big, bigger than actual monitor screen. If possible, a way to capture the node-tree boundary.

So far, I only screen shot limited to my monitor.

Thanks.

While its undoubtedly possible to do some tricks to make a huge screen-shot (automate panning and capturing the view, then joining up the tiles), Blender has nothing built-in to perform such an operation.


Saving a character so it can be opened in a seperate blender project This is very probably a noob question, but.  I have made a couple of characters on Make human, then imported them to blender where i had to re-assign all of the textures etc.  Once i got the character looking right again, I saved it as a .blend file, as well as a collada and an Obj file thinking one of them was bound to work right.

Well, long story short, when i imported my character into my scene, all my materials and textures were back to default and in need of resetting.

I'm not sure if i am doing something wrong in my saves, if I'm saving to the wrong format, or if it is something i have yet to even think of. I'm using cycles as my render engine)

Anyone wanna help me out and give me the idiots guide to how to save your textured character so that when you import it it is all ready to go?

seems that what i have found thus far is very time consuming each time you want a new character in your scene.

File/Link or File/Append will be useful.

Save your character as a .blend file.  From the "set" file use the menu option File/Append or File/Link. You will get the best results when when Append or Link from one .blend file to another .blend file.  File/Append ... File/Append is a great way to reuse and asset and animation across files.  Linked Libraries.  Link below.

The blender terminology for this is File/Append or File/Link.  Import is probably not what you want.

When you File/Append ... Choose the object or Mesh or Armature or Group.  You will travel through a hierarchy  to find what you need. Blender will also link/append related items.  You can design Groups to be linked/appended.

See this link.
http://wiki.blender.org/index.php/Doc:2.6/Manual/Data_System/Linked_Libraries


How do you know if a collection has been clicked on by the user using Python? How can I create a panel that allows me to add custom properties (StringProperty, BoolProperty, etc) for Collections? I want to show a GUI in the object properties when the user clicks a collection in the outliner. To create a panel you normally inherit from bpy.types.Panel and implement the draw(). The poll() function can be used to determine if the panel should be shown or not. The obvious approach is to use this feature. But how would this poll() look like? How do you know if a collection has been clicked by the user as shown in the screenshot below.

When "my-collection" is clicked/selected I want to show a panel in the object properties. But how do I know  if a collection has been clicked?
Update 1

I'll try to clarify the issue a bit more. In the image above I've made the "Sub" collection active. When I print the name C.collection.name you see that it prints "Sub".  Now, let me make "Cube" active:

Now, when I print C.collection.name it prints "Sub" again; and although that's correct, that's not the info I'm trying to retrieve. I need to query some other context value which would give me the collection when "Sub" is active and "Cube" when the object is active.

It’s easier than you might think: Either get the collection in context (C.collection) or the collection of the active View Layer (C.view_layer.active_layer_collection). Both attributes return a reference to the selected collection in the Outliner allowing to access the name of the collection by using its name attribute to compare against.
Adding the following poll method to your panel class will only return True in case the selected collection is called MyCollection and thus display the panel:
@classmethod
def poll(cls, context):
    return context.collection.name == "MyCollection"

Code based on ui_panel_simple.py template:
import bpy

class HelloWorldPanel(bpy.types.Panel):
    """Creates a Panel in the Object properties window"""
    bl_label = "Hello World Panel"
    bl_idname = "OBJECT_PT_hello"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "object"

    @classmethod
    def poll(cls, context):
        return context.collection.name == "MyCollection"

    def draw(self, context):
        layout = self.layout

        obj = context.object

        row = layout.row()
        row.label(text="Hello world!", icon='WORLD_DATA')

        row = layout.row()
        row.label(text="Active object is: " + obj.name)
        row = layout.row()
        row.prop(obj, "name")

        row = layout.row()
        row.operator("mesh.primitive_cube_add")

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

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

if __name__ == "__main__":
    register()

Further reading:

How to create a custom UI?
What do operator methods do? (poll, invoke, execute, draw & modal)


Creating fantasy crystal-like object to composite in a photoshoot first post here. I'm a beginner with Blender so I'm trying to get some advice on how to make the material part of a diamon/crystal type thing I'll add in a photoshoot.
I already asked this somewhere else so I'll post the screenshots with some reference images and more details about it.
I tried looking for tutorials online but none of them actually helped that much, so if anyone knows some tricks or a good tutorial let me know!
(The last two pics are the material nodes I used respectively for the top and bottom crystal)

Maybe this:https://www.youtube.com/watch?v=6q-vCT-ZuV8
Or this: https://www.youtube.com/watch?v=fxY4uq8kH0Q
tutorial will help??


yellow rectangle around the camera in 2.8 Beta Can someone please explain the purpose and function of the yellow rectangle around the camera? It seems to have a mind of its own. I'm also having trouble keyframing camera movement and am not sure if it's related.

It is part of the new gizmo system.

Certain object types have a new gizmo that allows controlling specific object properties directly from the 3D view.

For cameras you can control the focal length.

For spot lamps you can control direction and angle.

Other object types have different controls.


How to convert hair particles I have simple sphere and added some hair particles. I want to export it to obj file and i have converted the hair particles in modifier tab. And exported but i did not get the hair particles just normal sphere.
How can i convert the hair particles.

When you convert hair particles you get vertices connected by edges. Most programs will only draw faces so you won't see the hair outside of blender unless you create some geometry that can be drawn.

Convert the hair particles to mesh.

Convert the hair particle mesh to a curve. ⎇ AltC-> Curve from Mesh/Text

Add a bevel to the curve - effectively turn each strand into a tube. For the fill option, front and back will give a quarter tube, half a half tube and full will fully enclose it. The depth setting determines how big the tube is while the resolution will subdivide the tube to give a more rounded result, a resolution of zero will give a four sided tube with fill set to full. You can use the extrude value to give them an oval shape. Note that extra resolution increases the geometry to export but would provide little variation to the visual result of the small hair mesh.

Convert to mesh. ⎇ AltC->Mesh from Curve.

Export.


Make a dynamic text object How to make text object so the 'text' is updated automatically to show/display its current location. For example : the text showing the z position that will update automatically when i move the object up or down.

You can do it using Animation Nodes (link to the site here):

Get the text as object transform input in order to have its coordinates.
Convert the location to text.
Use it as text object output.


Baking trouble using a cage I have created a high poly model of a castle wall and I would like to save on rendering time by baking the detail to a low poly counterpart.

I followed this Tutorial : https://bit.ly/2Iy3WF7

However when I come to bake I get an error message saying the following : Invalid cage object, the cage mesh must have the same number of faces as the active object.

I'm assuming the active object is the low poly mesh. But in the image example you can clearly see that they do have the same number of faces. is this a bug or have I done something wrong.

When selecting the active object use the Ctrl + Click instead of Shift + Click.


How to "add vert" in blender 2.8? I'm following a tutorial called "Fuel Station - Blender 2.8 Low Poly 3D Modeling Tutorial", and the teacher is adding a vertex typing "Shift+A" that show a Mesh Submenu -> Single Vert -> Add Single Vert, just like this:

The problem is: when I try to make the same, it only shows this:

What can I do?

Just solved it. You need to install the add on. Go to Edit -> Preferences, type extra in the search box at Add-ons submenu, select both add-ons and install them. Just like this:


Problem having seamless texture on mesh I'm making a piece of armor to use a game in a game engine and I've been generating by own custom seamless textures to come up with a pattern. I'm trying to create a gambeson, and thus I need a quilted like pattern very much like this:

However, no matter how I unwrap my model, I'm constantly getting seams or the UV's just seem to stretch for some reason. I've also tried using UV Squares addon but that doesn't seem to help much either.

Here are some of the problems:

Can someone tell me what it is I'm doing wrong? I just can't seem to figure it out.

Blend file:

Seams are a very real part of most clothing items.

The main thing wrong with your UV's is their alignment.

Basically you need to add seams where they would be on a similar real world piece of clothing. I added vertical seam from under the armpits to the waist.

Unwrap and rotate the UV islands so that they are correctly aligned with the texture. Then straighten (align to X to Y) edges where ever it makes sense to do so. Pin these straightened P edges, so they don't move and Unwrap a second time.

The rest is tweaking here and there, with one eye in the 3D editor to see if it is an improvement or not.
To check for stretching sometimes it helps to switch to have a UV grid on the model. Other times (but I find a little less useful), is to enable the Stretching Overlay in the UV Editor.

To re leave some of the stretching in the original sleeves unwrap I added a seam close to the top of the arm then unwrapped a second time. Moved the two islands close together then tweaked the vertices along the seam to align the up together again then used the Weld tool (UV Editor) to weld the two edges back together again.

The result is not perfect by any means...  more time and more tweaking :)

Doing this has reminded me about the UV Magic addon that ships with Blender. I haven't used it yet but there appears to be some very useful tools included. Checkout the UV Sculpt tool, illustrated in this Video at 8:20  https://www.youtube.com/watch?time_continue=533&v=BKZX3Xac7X4&feature=emb_logo )

Blend file


How to make my hillshade bright as given in the link? I am trying to make a hillshade of a terrain. The issue I am facing is that the model looks dull as like the default models available in blender. I am attaching the screenshot of my workspace and nodes.
My model

Node

The output I am trying to achieve is as below https://somethingaboutmaps.com/Shaded-Relief-in-Blender

The tutorial which I followed is https://somethingaboutmaps.wordpress.com/2017/11/16/creating-shaded-relief-in-blender/

This is matter of lights in your settings as also said susu in the comments.
Just an example from your file (but with another texture because you did not pack your texture in the file).

Only things changed are the lights.
I've changed the point light by a sun light and gave it an orientation and a strength of one (= one solar unit, our sun).

And added an environment texture (you can take hdri textures from Blender's install directory, in the data part):

From that, up to you changing color, texture, light intensity, etc.


Trouble selecting correct object in viewport After switching from Maya to Blender I noticed that I can't select meshes as precisely as in Maya.

In Maya you select exactly what you clicked on, it doesn't matter how far the object is from the camera, you always get what you clicked on. In Blender it's fairly hard to select a specific mesh among other meshes, it seems Blender is trying to "help" me and correct my selection (like auto-aim in FPS games on console). I spend too much time trying to select the right mesh. Its not only time consuming, but also very annoying. I have to switch between shaded and wireframe modes, sometimes use strong zoom and hide functions to select the right mesh.

Is there a way to switch this "auto-aim" selection off? I would like to be able to select meshes just like in any other 3D program, by clicking exactly on them.

You can also try changing the selection mode under User Preferences.  There are two options available now for selection.

OpenGL Select
OpenGL Occlusion Queries

OpenGL Occlusion Queries is the newer, and faster method which seems to work better on AMD Radeon GPUS.

You can also use shift+b to draw-out a rectangular selection that will cause the view to zoom in on the selected location.   Picking objects tends to work better when you are zoomed in closer.

shift+c will zoom out out to fit the scene.  Using these two shortcuts, you can quickly navigate to whatever object you would like to select and work on.


problem projecting a photo onto a mesh I want to animate a quick shot of a road (photo) where my camera moves slightly.
So I'm trying to project a photo on a mesh on a simple "tunnel".

I've read this topic, Project photo onto mesh UV texture, and I've built a scene setup using Fspy.
Once in Blender, it seems that everything is correct; my mesh does match the picture.

But once I unwrap my mesh, it doesn't work at all as expected :

Project is here if you want to have a look at the file.

What am I doing wrong ?
Thanks for your help.

This is due to the extreme perspective that forces high errors on simple geometry as mentioned by @jachymmichal.

One way is to add geometry to your cube before projecting UVs from view. Here is a way using the subdiv modifier:


Getting pynodes geometric node to work I downloaded the geometric node from git, and copied it in the addon folder of blender 2.67. Tried with 2.67b and a self-compiled svn version, in both, I can't enable it in the user preferences. Does anyone know how to get it to work ? I didn't find any readme.

Edit, more info :

I downloaded geometry_nodes from https://www.gitorious.org/blender-trunk/addons/trees/geometry_nodes/py/scripts/addons/geometry_nodes
Extracted the folder geometry_nodes in my ~/.config/blender/2.67/scripts/addons/ folder
it appears in user preferences under add-ons but I can't activate it. Launching Blender from the command-line doesn't give any help (no error given in output)
Trying to launch init.py gives following error in the console :

  .config/blender/2.67/scripts/addons/geometry_nodes/parameter.py", line
  433, in register_mod_pass
      from geometry_nodes import modifiers
  ImportError: cannot import name modifiers

The version of geometry_nodes as of commit edbdbc8fea539 does a small check that isn't actually really used yet. This looks to be part of a work-in-progress that is as of yet uncompleted. To get these nodes running you'll have to modify modifiers.py and comment out or remove lines 46 and 47:

#if not isinstance(datatype, TypeSpec):
#    raise TypeError("Expected TypeSpec datatype")

After this (re-)start blender, enable the addon and play with the geometry nodes :)

Note that as of this writing the above mentioned commit is the latest and the only one in 24 days. Looks very much like current development is on hold.

A small screenshot of geometry nodes in the node editor:


I can not make the normal map bake in cycles I can not make the normal map bake in the blender cycles 2.79 I already did the UV mapping right, I tried everything, the result is all rough as in the image below

How can I fix this?

here is the .blender file

These "artifacts" are usually the result of a ZERO value in Ray Distance when bakeing, so try to change the value in a GREEN rectangle seen on the image below to a non-zero (0.1 or 0.05 should be fine).

Hope it helps André.


How can I put a modifier at the top of the modifier stack? I have a modifier that I want to put at the top of the modifier stack.

How can I do this in python?

Suppose you have two modifiers like this:

Note that the second modifier is named "Subsurf".  You can move it up like this:

bpy.ops.object.modifier_move_up(modifier="Subsurf")

You may need to set the active object first, as described in this answer:

my_object = bpy.context.scene.objects['Cube']
bpy.context.scene.objects.active = my_object

If your modifier is in an unknown position in the stack, you can use a loop like this to bring it to the top:

while my_object.modifiers[0].name != "Subsurf":
    bpy.ops.object.modifier_move_up(modifier="Subsurf")


How do I get two way coupling in FLIP Fluids? I'm on Blender 2.91 and I'm trying to make a simulation with Suzanne being pushed around by liquid. No idea how I'd approach that though. Obviously I'm making it a rigid body and a fluid obstacle, but what should I do from there? There's no FLIP two way coupling option, is there?

Well flip and manta dont support this.
However maybe you can fake it.
If you use a paint canvas for displacment you can mimic it a bit.
If the water moves wild your out of luck though.
There are some raindrops examples that might work.
Else you need some proffesional solver and an openvdb import
(if it supports that) to render it in Blender.
btw there's a popular youtube channel 2 minute papers has lots of research about this topic, maybe through that you can find software that does it.


Getting low resolution render images When i am rendering my scene in 1920×1080 at 100℅, and with a sample value of 500, I am getting a low qulality image which got rendered in just 8 seconds. How can I fix this!

Recheck the samples and if they are 500 samples then you can enable denoising after going to 2 sphere icon which is second icon.


Help with 3D data representation algorythm I've run into a few issues regarding a blender script I am working on to accompany another program I wrote that transforms analog sound into a data set representing the amplitudes of the frequencies in that sound sample over time. I now want to use blender to transform my data into a 3D model that would, effectively, be a 3D representation of music. It's my first time working with Blender/Python scripting, so your patience is appreciated!

Context
From a conceptual standpoint, here is what the script should do:

Create 513 (number of frequencies sampled) collinear vertices
Connect the vertices with a line(face?)
Set the z value of each vertex to the corresponding amplitude for that specific frequency at t=1 represented by the vertex (we now have a 2D jagged plane)
Extrude the plane by delta time
Adjust the new set of vertices for amps at t=2

...repeat this process of adjusting and extruding until all t values are exhausted

The issue I repeatedly encounter as I work on this code is referencing / selecting individual vertices. In the 3D editor, I can simply right click, or control right click, to select point(s), and that is basically the functionality I need to replicate at many steps in this process.

For example, to create the first row of vertices, I wrote the following code:

counter = 0
bpy.context.scene.cursor_location = (0.0, 0.0, 0.0)
for x in range (0,513):
    bpy.ops.mesh.primitive_vert_add()
    counter = counter - 0.1
    bpy.context.scene.cursor_location = (counter, 0.0, 0.0)

Then, to connect these collinear vertices, I have:

bpy.ops.mesh.select_all(action='TOGGLE')
bpy.ops.mesh.select_all(action='TOGGLE')
bpy.ops.mesh.edge_face_add()

Now, though, I need to go back and start adjusting z value for each vertex I created in this line, and I do not know how to reference them. Ideally, I want to store them in an array at the time of creating them, but again, I am at a loss for associating these vertices with object references that can be operated upon.

I will also encounter an issue following the extrusion, where a new set of 513 vertices is formed. For those, I will only know their xyz location and will have had no opportunity to build references to them unless Blender already does that by storing references to all vertices in a mesh (I've read about it, but still cannot access that data set if it exists). When it is time to set z values for these points, I will not know how to reference them.

Question
How do I reference individual vertices knowing only their xyz location in space and operate on them either individually (for z movements) or as a set (at extrusion time)?

Thank you for your help! I can't wait to finally see (or print!) my audio data set in three dimensional space.

An example

import bpy
import bmesh
from random import uniform

mesh  = bpy.data.meshes.new("Mesh")
obj   = bpy.data.objects.new("Mesh", mesh)
scene = bpy.context.scene
scene.objects.link(obj)

bm = bmesh.new()

verts_b = [bm.verts.new((i, 0.0,               0.0)) for i in range(20)]
verts_t = [bm.verts.new((i, 0.0, uniform(1.0, 3.0))) for i in range(20)]

# create edges
# for i in range(19):
#    bm.edges.new((verts_t[i], verts_t[i+1]))

faces = [
    bm.faces.new((
        verts_b[i]  , verts_b[i+1],
        verts_t[i+1], verts_t[i]
    ))
    for i in range(19)
]

result = bmesh.ops.extrude_discrete_faces(
    bm, faces=faces, use_select_history=False)

for f in result['faces']:
    amount = uniform(1.0, 2.0)
    for v in f.verts:
        v.co.y += -amount

bm.to_mesh(mesh)
bm.free()


How to use all the audio and video strips in the VSE as a video texture? I've been able to use images in the past to create a video texture, but for this animation I've inserted several movie clips and audio in the video sequence editor.

My question is, is there a way to simply amalgamate all those video and audio strips into one thing that can be opened as an image texture?

The idea is that I could have the TV I modeled playing various scenes at different times in the animation.

Thanks!

EDIT:

I figured it out.  It's a bit of an awkward method and there might be a better way, but it works.

STEP 1: Plan your scene with audio and video clips you want to add on your TV in the VSE.

STEP 2: Render into Xvid rather than AVI jpg (to ensure audio is captured).  Make sure you check the sequencer in post procesing, not the compositor.  Otherwise, when you render your animation it will render all your objects and scene rather than the strips in the VSE.

STEP 3: Save your rendered video as something like "audio for tv" because in reality, you are going to import it again to get purely the audio.

STEP 4: Go back into the VSE and render your strips to jpg or whatever image format you prefer.  Use a separate folder as there will likely be a ton of images.  These will be the images for your TV screen.

STEP 5: In the VSE delete all your strips.  Add the video you just made earlier and erase the video strip, keeping the audio.

STEP 6: Now add your images you rendered for your video texture in the texture panel as an image sequence (you can add actual video files to make video texture but my preference is image sequence because if Blender crashes or you have to stop the animation for whatever reason, you can always finish where you left off).

STEP 7:  Lastly, go back to the render panel and check the compositing box under Post Processing and uncheck sequencer to render your animation.  If you don't do this, you won't be able to render your images (when there is anything in the VSE and you try to render your scene as images Blender won't render them unless you remove all strips in the VSE or have sequencer in the render panel unchecked...a little sneaky reason why you frustratingly can't render and often don't know why).

No the VSE is simply a post production tool at the end of the 3D chain. You'll have to render the sequence out then import that as a video texture. You cannot define a scene output for use in other 3D elements. However you can use Compositor or VSE in another scene's compositors or VSE editors.


What is a way to sculpt/model clothes that aren't stuck to the body? So I know how to sculpt tight clothes onto the body (plane > merge at center >modifiers like shrinkwrap > make verteces) and I know how to make wider clothes that are stuck on the body (sculpt them and then retopologize).
But how do I make thinks like e.g. capes or hoods? Or what's the method called so I can search it up? :)

You should give some details about the style of cape, if it is supposed to be animated, etc... There are several approaches, like modeling it, sculpting it, or using cloth simulation.
You can sculpt it:

Prepare a vertical plane, subdivide it a bit:

Use brushes like the Draw brush to dig or bump the shape (press Ctrl to dig, you can also try the Crease brush for more sharp details):

You can also use the Grab brush to deform the shape. There should be even more convenient brushes in next Blender that will easily allow to bend the mesh:

Or you can begin with a Cloth simulation:

Create a plane, give it a group at its top edge. Give it a Cloth physics, with for example the silk settings, in the Physics panel > Shape choose the group as the Pin Group. Select the body (here a simple cylinder) and give it a Physics > Collision:

Play the animation. Stop it when you're glad with the result, and in the modifiers, apply the Cloth. Now you can edit it the way you want.


When I move Parent Bone another bone thats a child of that parent bone's object moves another direction When I move Parent Bone another bone thats a child of that parent bone's object(the eyebrow) moves another direction. Im not the best explainer so heres a GIF

This is a so-called "double transformation": the bone moves the origin of the eyebrow (and all of its vertices follow) but the bone moves also the vertices away from the origin; so vertices move double the distance of what it's expected. Delete one of the two parenting (bone weight or object-bone parenting).


Boid particles will not climb I'm trying to use Boid particles to create an ant-like insect swarm that moves towards a goal and climbs over everything in its path. My operation and collision tests have been successful so far, with one big exception: I can't get them to climb goal objects.

My approach - based on research - has been to create an obstacle mesh for climbing, enable its collision physics, then set it as a Goal object in the Boids operation stack. The particles do travel towards the goal (in this case, a pyramid), but then they simply bounce off the side and move around.

Here is a screencap of my test setup:

Assuming that 'goal' is where the boids should end up, and the pyramid is an obstacle to climb over, this is the desired outcome. In this case, the pyramid should not be a goal for the boids.

The key to get the boids to climb over the pyramid is to make it 'sticky' using the stickiness collision parameter for the pyramid and plane.

If the stickiness is set to 0, then the boids will flow around the pyramid like below:

The basic setup to get this result is as follows:

Create a scene with a plane, a pyramid, a particle emitter (an icosphere in this example), and a goal object (the text).

For the icosphere, add a particle system. Set it up as shown.

Add collision physics to the plane and pyramid, set the stickiness as shown.

Play the animation...

The blend for the animation above is here:


How do I make a herringbone pattern? I'm trying to create a herringbone pattern that will wrap around a cylinder. I'm assuming that there's a way to do this using the brick texture node but I can't work out how to alternate and/or manipulate the rotation of bricks within the pattern itself?

Edit: The pattern is not the same as that than in the answer that I'm being told this is a duplicate of - that's not even close to the pattern I'm looking for. I'm looking for a herringbone pattern as in the example below, not just simple zig zags. Any actual help greatly appreciated!

I think you could use a texture map instead of a procedural map.

I made a seamless tile using your image.

You can play the dimensions using a mapping node.

See the image below:


Change color by radius So I am currently working on a CAD rendering and decided to give Blender a try instead of Keyshot. One part is a black ring with engraved writing (silver/white) on it (in the mesh since it is a stl import). I thought just like color by z hight it should be possible to assign color by radius -> lower parts of the ring white and higher parts black. So my approach was calculating the radius and input into a color ramp set to constant.

Also tried to add a Mapping Node to scale the vector etc. but no luck with that. I am quite new to blender so I guess my understanding of the texture coordinate object vector might be wrong. Switching the xyz outputs didn't help either.

Maybe someone could help me out here.

Your node setup looks correct, although it could be made slightly less verbose by making use of the Vector Math: distance node.

I've managed to make it work on a torus. Perhaps you should try:

Making sure the origin is in the centre of the ring.
Tweaking the ColourRamp slider's Pos values so that the results of the previous node operations fall in their vicinity. As of right now, yours are set to 0 and 0.077, it seems; for me the spot was around 0.9 .


Is it possible to change view while using circle selection? When using selection modes like circle selection (C) or box selection (B) I often would like to change the view to select more faces, vertices or edges that are hidden because of the angle view. Apart from hitting ESC then change angle of the view then press C again is there a hot key to be able to change the view by pressing it and using the mouse buttons/wheel without having to press C or B again afterward?

Thank you

It is not, unfortunately.

It is a known limitation of the current modal operator's design. While a modal operator is running, like Circle Select, Border Select, Knife Tool, Move, Rotate, Scale, or any other, Blender can't modify the view.

The opposite is also true: while doing view transforms like Rotating the view or panning, no other tools can operate.

There were some rumors about overcoming this for future 2.8 versions but no definite decisions.


Ultra bright points of light randomly appearing I've been trying to create a stormy ocean with lightning, but there are a few random superbright pixels that blow up when I enable fog glow. I've tried turning the threshold to 1000, and they still appear. These are all in front of the "ocean" but in previous renders I had 1 point of light in the sky as well. Denoising is off. I tried turning off the mist pass. What could possibly be causing this?
Blend file(Waited 30 mins for giantcow to process the file, and it hasn't moved at all so Gdrive it is): https://drive.google.com/file/d/1COR2JfXNYdBZ_g6ufzyd8fvssPJxknWB/view?usp=sharing
With fog glow:

Without fog glow:

Compositor Nodes:

They seem to be very bright specular highlights on the waves :

The fact that "Point.001" has a power of 3MW (!) is of course in cause ; but I guess you won't get the same dramatic effect if you lower that value.
What you can do is render the waves and the lightning in two distinct View Layers (formerly "Render Layers"), apply the fog glow only to the lightning layer, then merge the two layers with a Mix or AlphaOver node.


Assign shortcut to Lock Camera to View Instead of pressing N, opening the shelf, scrolling down and searching for the option Lock Camera to View, and then check mark. Can I create a keyboard a shortcut for lock camera to view?

Go to User Pereferences/Input tab/3D View/3D View (Global)
There is no entry for "Lock Camera to View", so we will add a new one.
Click "Add New"
Open the "none" line that was created
In the text field which says "none", type: wm.context_toggle, and press ENTER
A new text field labelled "Context Attributes" appears. Type: space_data.lock_camera, and press ENTER
Define the shortcut. (Some more trial and error could be necessary to find a free one). The shortcut should work already.
Don't forget to also press "Save User Settings" in the User Preferences window.

In the following screenshot I just added the shortcut Ctrl-K:

Also see this blenderartists thread.


How to make an object move independently but also with a parent object? I am trying to make an animation of a briefcase lock where the lock spins to a code then the briefcase opens. How do I make the cylinder locks spin on their own but then move with the top of the briefcase when it opens? Thanks.

You should Shift+Click on all your cylinders first and then on the top of the briefcase lastly to make it the active object.
Then press P to Parent all the objects you selected to the last one you clicked (the top of the briefcase).
This will let you move the briefcase without affecting the individual transformations.


Question about volume samples I just want to know if I am understanding this correctly.

Lets pretend my domain is 18 vox wide, if I want Cycles to render all the way through, do I need to set the volume samples to 18?

Below I have it set to 2, does this mean it will only go 2 voxels deep and then stop?

No, you are confusing volume samples, volume bounce depth, and ray-marching steps, which are all different controls.

To start with, a short overview of how volume rendering works. As a ray passes through the volume, it is checked at a series of steps via a process known as "ray marching". Here's an example illustration, from this answer by the user sambler:

When using the volume scatter shader, there is a chance that the ray will experience a "scattering event" at each step. The higher the density, the greater the chance of a scattering event. For the volume absorption shader, the energy of the ray is reduced at each step. For the emission shader, the energy of the ray is increased at each step.

Ok, now, a breakdown of volume step size, volume bounces, and volume samples.

Volume Bounces

The control you pointed to is the volume bounces control, also sometimes called volume depth. This controls the number of bounces of multiple scattering that will be computed. Depth of 0 disables multiple scattering, leaving you with single scattering: Volume scatter shaders will bounce once, and after that the ray will exit the volume regardless of if it should experience another scatter event. If volume depth is non-zero, it is the number of additional scatter events a ray is allowed to experience.

Multiple scatterings are needed to for some physically accurate lighting situations, such as making clouds appear white instead of gray. However, each bounce takes computing time, and increases the chance for noise. So this control limits how many bounces you can have.

In most cases you will want to set this to 0 or 1. Higher values may be needed, but can increase render times a lot. See my answer here for some methods for dealing with bright volumes: Realistic smoke?

Volume Steps

Volume steps are controlled from the Geometry panel:

The "max steps" control is roughly what you were envisioning in your question: it's the maximum number of steps the ray is allowed to take before it gets shut down. However, the steps are not automatically snapped to individual voxels, but rather are a simple distance control. "Step size" is in meters, even though for some reason it does not display units. Step size is a set as a world-space distance rather than a number of voxels because volumes don't need to have voxels. In fact, as Cycles sees it, voxels are something that 3D textures, not volumes, have, and those just sometimes happen to be used to texture volumes.

Smaller step sizes better capture detail in fine volumetric structures, and reduce the grainy appearance when you undersample the volume. However, smaller step sizes will take longer to render.

For volumes defined by a voxel grid, the optimal step size is one-half the length of each voxel. You can find this for Blender's smoke sim by getting the dimensions of your domain, and plugging the length of the longest size into the formula: voxel size + length / (base res * (hi-res level + 1)). So a 10m domain with 80 res and 2 hi-res divisions would be 10 / (80 * (2+1)), or about 4cm.  (so step size is set to half that, 2cm, aka 0.02)

Volume Samples

If you are using Branched Path Tracing you will have an option under the samples panel to set a number of volume samples. This is the number of times a ray will branch to continue the path after a scattering event.

Higher values will reduce some sources of volume noise, such as from using volume bounces > 0.


I want to make a stretch effect? I'm trying to make an effect using the Blender Compositor, but I didn't know how to do it, and please I want the solution using the compositor not by adding more objects (Lens).

Here is a picture to explain what I want to do :

Final result:

Composition nodes:

Overview:

I don't know your scene setup but mine is just plane with procedural stripes.

After render you just need to connect couple of sets - Lens Distortion + Scale nodes and adjust values as you like. X value will stretch pattern, Y is for straightening up after Lens Distortion.

Blend file:


Do not repeat the texture on Collada export? I am trying to apply a UV mapped texture to an object and export it in the Collada format. The result is not what I designed in Blender. Here's the simplest procedure that shows what I did.

Start with the blank file and add a cube mesh.
Select texture viewport shading.
Unwrap the cube mesh (Smart UV Project).

In UV/Image Editor, open random image.
Position and scale islands so that the image is only on one side of the cube (that's how I want it).

The texture is now repeated on all sides of the cube in the viewport.

From this point on, I have three choices.

Don't assign any material

Export to Collada.
Cube is grey when viewed in MeshLab. No material, no texture, nothing. And that's fine.

Assign the material

Assign a new material to the cube (it did not have a material before).

Without changing any material properties, export to Collada. Or do make changes, the result is the same.
Cube is black with texture applied and repeated.

Why is there any texture on the cube when the material doesn't have any textures by itself?

Assign the material and the texture

Assign new material to the cube.
Add new texture, set it as image, load the same image as texture as when doing UV mapping.
Image Mapping > Extension, set to Clip.
Mapping > Coordinates, set to UV.
Mapping > Map, set to UVMap (only choice available).

Observe that none of the changes made make any difference in viewport (in render, however, they do).
Export to Collada.
Cube is black with texture applied and repeated (same as before).

Collada model represents what is viewed in the viewport, and none of the changes made in material/texture after making UV mapping get reflected on the exported model. How to get them exported?

Notes

Using Blender 2.69 with Blender Render.
When exporting to Collada:

Include UV Textures is checked.
Include Material Textures is checked.

As far as I know Collada (and most other export formats for that matter) concern themselves mostly with exporting geometry, UV's and some times animations and constraints, not materials or textures.

Materials are very tied to the rendering system they belong to and can't generally be easily exported between applications apart from some basic properties.

Whatever changes you make to your material and/or texture settings are not at all guarantied to be correctly exported, and will most often get lost, many of them are (as you already stated) not even supported as in the viewport as rendered preview (like the clipping setting).

Now I do not know Collada export very well, nor do I know MeshLab software, but if you want your texture to show up in one face alone I'd advise either to use a different material for that face, or to unrwap your mesh accordingly, having in mind that by default all textures will tile infinitely.

That probably means setting the UVs for the faces that should have no texture to 0,0 like for example scaling them down to one corner of the UV editor.

For any other more complex material properties it's probably better to do it in meshlab or whatever final destination application you will be using.

Also see .fbx export why there are no materials or textures?


Specific object not being affected by any forces when a cloth I have an object that I'm trying to act as a curtain that I have been slowly working on trying to simulate hanging it up onto a frame.

I have simulated it a few times applying the cloth modifier as I hook up each corner to where I want it to go. The problem is now I want to use a little bit of a wind force to push it out a bit, but the problem is the object won't be affected by any force when I've set the cloth modifier on it.

Attached is my .blend file:

On layer 3 is the curtain object (purple deformed plane), and a test grey plane. Both with the cloth modifier set on it. I have added a wind force field too. You can see that only the test grey plane will respond to the forcefield, but not the curtain.

I've tried appending it into a new file but that didn't fix it.

Edit: It may be a problem with the vertices as I joined the curtain object to the test plane object (into one object) and let it play and the test part was still affected but the curtain part not. I did accidentally mess with the weight painting if that might have anything to do with it

Solved!

Seems like subdividing a plane too many times can exponentially decrease how little a force will act on it. I had to set the force multiplier of wind on the cloth to about 50 to see a change


What value should I increase to reduce noise for subsurface scattering, volume scatter, etc.? I'm on an AMD machine, so GPU rendering is off the table, but I don't mind a lengthy render as long as the end result is good.
So far I've tried:

Rendering at 5000 samples

Various indirect/direct clamp values

Increasing volume sampling max steps

increasing volume bounces (in light paths)
And in all likelihood, a few things I've forgotten.

This render took 40 minutes with tons of settings cranked up, but still has a lot of visible noise despite being fairly small:

I'm using a volume scatter shader to add fog, one transparent plane using a procedural texture for the smoke.
It's worth noting that while I do not have a high-end machine, I also don't have a particularly horrible one either.

You can switch to branched path tracing and use its subsample controls. Increasing subsurface sample level will improve noise for SSS, volumes for volume scatter effects Note that volume samples only affect indirect light, meaning the noise that comes from volume bounces being > 0. For other volume noise, adjust lamp sampling values.

See this question for general info about branched path: What is branched path tracing and how is it useful?

I normally recommend using the "square samples" option with branched path, as it allows you to work with simpler values when juggling all the subsample counts. "square samples" just, well, squares all the values being used for sample counts. So "4" samples becomes 4*4=16 samples. The reason for this is the more samples you have, the more samples you need to add to get a noticeable difference. By adjust sample counts in increments of squares, you ensure you're always getting a statistically significant addition for each sample level.