How to calculate centripetal force in BGE? Everyone knows how a racecar traveling at such-and-such speed can drive along the inner curve of a race course, tilted almost perpendicular to the ground.
This is an example of centripetal force. There are a lot of fancy equations here to explain exactly what it is, but they don't relate to my question very well.

My game involves a character who can do pretty much anything that you could do in real life if you were awesome. This includes (but is not limited to) kicking people while airborne, throwing people back-flipping, running at Olympic speeds and punching people through walls.

I want to include a function that allows my character to run on walls, permitting his speed is sufficient. Example of this are found in Mirrors Edge and Jedi Knight 2.

I think this can be probably accomplished by adopting the face normal of a wall, playing an animation (differs from left to right) and decreasing personal gravity, but I haven't been able to get it to work like that. I've looked at these questions:

How to get the normal of the face which was hit in a collision?
Can gravity be disabled for a single object in the BGE?

but they haven't helped.

import bge
cont = bge.logic.getCurrentController()

own = cont.owner

ray = own.rayCast(own.worldPosition+(own.worldOrientation.col[2]*-(actor center from feet distance)),own.worldPosition,'',0,0,0)
if ray[0]:

    if own.localLinearVelocity.x>(stick speed):

        own.applyForce((0,0,9.8*own.mass),0)

        own.applyForce(own.worldOrientation.col[2]*(-own.mass*9.8),0)
        own.alignAxisToVect(ray[1],2,.5)


Weird sprinkles color Im brand new to Blender, so as many newbies do, I've been watching the Blender Guru Donut Beginner Guide. And when I got to render part, I found a problem: First image is dev look, and the sprinkles there have colors that I like, but when I switch to Cycles to render it, colors are getting a lot different(second image). Any idea how to fix this?

P.S. Here is the .blend file:
https://drive.google.com/file/d/1ndjYwAqxHL1UQNghsHvtlwXSDzfF-fOE/view?usp=sharing

From what I saw, you had a Subsurface in the material of your sprinkles. When I lowered it to 0, I seemed to get the color you were trying to get.
Hope this helps you!


How can I use Extrude Faces along normals without making different sizes? I'd like to make a low poly room in Blender, but when I try to add thickness to the wall and extrude the faces along the normals the smaller sized wall is thicker than the other. I want to make them the same size.
Is there any easy way to do it?
Thanks in advance,
Tobi

Already comments are very usefull ... so just a tip.
You can start with Solidify Modifier with Even Thickness enabled.


Moving Videos on Green Screen (This is in blender cycles.)
So I have a tank animation with a green backdrop and on that green backdrop I put a road so it looks like the tank is moving on the road. But the video clip of the tank is stationary so is there a way to move the video clip across the road backdrop to make it look like the tank is moving across the road? Also is there a way to reposition the tank like rotate it to make it aligned with the road backdrop or rescale it? I wish I could send a pic to make it easier but stack exchange crashes when I do.

(This is in the compositing node editor)
So my node set up is the army tank with green backdrop in a movie clip node connected to the image of the keying node which is connected to the 2nd image slot of an alpha over node which is connected to composite. The road image is in an image node connected to the 1st image slot of the alpha over.

How I would do it

Your best bet for scaling, rotating, moving, and animating all that stuff would be through the VSE.
1. In the compsitor remove the green background to make adding the background easier later on using the keying node.
2. Open blenders VSE and add in your newly rendered transparent video through SHIFT+A > movie
3.With your clip selected add a transform strip via SHIFT+A > Effect Strips.. > transform. Once there you can change the size rotation and location all from the properties panel on the timeline. Your probably going to want to keyframe the movement of the tank so using the timeline put the timeline where wish and using the transformation strip you can change how the tank looks relative to the frame. Hover over the location, roation, and whatnot and then press "i" to keyframe it.
4. After you render that run through the compsitor with an alpha over node and add your pic - that should do it.

References

https://www.youtube.com/watch?v=h0F5X4b7jug
http://blenderartists.org/forum/showthread.php?261401-how-i-add-or-active-keyframe-for-VSE-blender
https://www.youtube.com/watch?v=0PZ_cxjxexM


Import-Export images to planes not working I want to import an image as a plane, but when I go to download the addon, it doesn't come up.

Have you tried installing the addon manually? I'm not sure why it doesn't show up, so I went ahead and got the addon for you from my addons folder, try installing it as an external addon to see if it works https://drive.google.com/file/d/1FlUA9t1jur1BGJm_8ABI1kJeMC2xL33I/view?usp=sharing


Background Images - Overlay on top Is it possible to have a "background image" be an overlay with opacity control instead of being behind the mesh?

The default background image: (as the name suggests)

How I would like it:

"Answered by @MrZak"
There is a Back and Front option under the Background Images options.


3D manipulator is in wrong position my 3D manipulator is always in the wrong position. I have tried everything to make it work, yet nothing has. I have relaunched it, and everything I can think of.

I simply cannot work like this. Please help.

This is happening for one of several reasons, most likely because you moved the mesh while in edit mode changing the origin point (the little orange dot where the widget is).

Looking at the image, your pivot point is most likely already on the default Bounding Box Center and what you want is to have the widget on the object. So to fix, select the object in Object mode and set the object origin back to the object with CtrlAltShiftC and choose Origin to Geometry.


Is it possible to change material overtime by keyframes in swipe effect? So I watched disney frozen, and at the let it go song, i was wondering, how to change the material texture in a swipe effect (if I do it on AnimAll add on, it just changing dragly, so the texture are really messed up). The point is, i want to change texture from feet to head by swipe effect by horizontal line , not dragging all the texture constantly.
Sorry if my english is bad, im me and im new to blender

Using a simple gradient and color ramp will allow you to control two different materials for the same object:

Then is just a matter of animating the value for the mapping.


Model looks strange when zoomed out The head of my character looked completely fine as I sculpted it in perspective view. Obviously, adding the body required me to zoom out to view the entire model. By doing this, however, the head that I sculpted earlier looked completely different. It turns out that the head becomes more "orthographic" the more I zoom out. Is there any way I can view the entire body while keeping the head in its "perspective" form?

PROBLEM: The left image shows what the head looks like when viewing the entire body. Zooming out causes the facial features to be "scrunched", and the face looks flattened. Although the camera is pointed directly at the character, the entire head appears to be tilted upwards a bit. The eyes also seem crossed.

DESIRED: The right image shows what the head looks like when the camera is zoomed in, exactly how it looked while I was sculpting it.

You can change the "camera size" in properties object camera to enlarge your image while keep all light angle stay in place:

This is the thing that every photographer in real world want to increase, you can do it in Blender for free. Thank you, Blender.


How can I see the normal data of a face in Blender 2.9? I'm looking for a way to see the normal data of a face, represented as x, y and z in Blender 2.9x. Sounds simple, but I can't find the option anywhere. I seem to remember having the option in 2.79.
Just to clarify: I don't want to see the normal. I want the data.

Like ZargulTheWizard said, scripting was needed. It turned out I had the script saved in a file from years ago. I'm a bit reluctant to post the script as I'm fairly certain I didn't write it myself, but I can't find the source when searching. So in order to help others I'll post it here. If you are the author, please let me know and I'll give credit accordingly.

This script will create an additional property in the "Normals" menu of the "Object Data Properties" tab:
import bpy
import bmesh
from mathutils import Vector

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

    me = context.object.data

    if me.is_editmode:
        bm = bmesh.from_edit_mesh(me)
        if bm.faces.active is not None:
            row = layout.row()
            col = row.column()
            col.prop(context.window_manager, "active_face_normal", text="", expand=True)
            row.prop(context.window_manager, "active_face_normal", text="")

            if context.window_manager.active_face_normal != bm.faces.active.normal:
                context.window_manager.active_face_normal = bm.faces.active.normal

    else:
        p = me.polygons
        if p.active is not None:
            row = layout.row()
            col = row.column()
            col.prop(p[p.active], "normal", text="", expand=True)
            row.prop(p[p.active], "normal", text="")

def upd_normal(self, context):
    bm = bmesh.from_edit_mesh(context.object.data)
    bm.faces.active.normal = self.active_face_normal.normalized()

def register():
    bpy.types.DATA_PT_normals.prepend(draw_func)
    bpy.types.WindowManager.active_face_normal = bpy.props.FloatVectorProperty(subtype='DIRECTION', precision=3, update=upd_normal)

def unregister():
    bpy.types.DATA_PT_normals.remove(draw_func)
    del bpy.types.WindowManager.active_face_normal

if __name__ == "__main__":
    register()


Use a mesh as a path with correct tilt information for use with "duplicate frames" The first picture shows the mesh, I'm looking for a way use the duplicate frames feature to make the object follow that "path" as it is shown in the second picture with an actual path.

I guess the task is mainly to convert the mesh into a path with the correct tilt information but I'm open for every solution.

First create a loop cut in the middle of your Path,

Then press CtrlI while the loop cut is selected to select everything appart from this exact edge and delete. Or if you want to keep the path you have to just duplicate this loop cut and Separate it by Selection, using P key,

After that you have to convert this edge into a Curve, to do that press AltC > Curve from Mesh/Text.

Now you have to get your model of the planch,

Give it an Array Modifier, and set the spacing between each planch as well as the number of the planches to fit the Curve.

Finally apply the Aray Modifier and add a Curve Modifier, then choose the Curve (it is propably going to be under the name of PLANE)

The Result


How to quickly rename an object in 2.8+ (like with the Item section in 2.79) In 2.79 there was an "Item" section in the Properties Panel that allowed the active object to be renamed quickly any time.

This made it easy to label objects quickly, so keeping an organized nicely labeled .blend file was no biggie.
In 2.8+ however, I can't find that section, or any other part of the UI where an object's name can be double-clicked and quickly renamed - except the Outliner.
Using the Outliner for that is fine when the .blend is small and there are only a few objects, but once you have more complexity and are dealing with nested parent-child hierarchies you may not be able to see the active object in the Outliner without drilling down. At which point one is tempted to start thinking "ah, forget it... maybe 'Cube.036' is descriptive enough". But that's not really exercising best practices, and cutting corners in the short-term can cost time in the long-term if data is too disorganized.
Is there perhaps a similar way to quickly rename objects in 2.8+ that I am unaware of? If there is, I'd like to use it. Thanks!

Use the F2 key after selecting the desired object either in the 3D View or in the Outliner.


What's the difference between refraction and glass shader? I have been experimenting with refraction shader and glass shader (using cycles render) and i noticed that a sphere with refraction shader looks almost the same compared to a sphere that has glass shader.
1)The only difference i noticed with the refraction shader compared to the glass shader is that when a light ray enters the material (that has refraction shader applied), the light ray ,that enters the material, changes once direction because of the ior (but cant bounce back) and when the ray exits the material it can't bounce back ,inside the material, but it can still change direction(because of ior) when it comes out.
Can someone help me spot out the difference?
Is 1) correct?

Firstly I'd like to point out that shaders are called BSDFs in cycles, and raytracing in general.

The difference is that the glass BSDF is essentially a mix of a refraction BSDF and a glossy BSDF - it reflects light as well as refracting it. The glass BSDF is designed to make glass and similar materials easier to simulate - otherwise you would manually need to mix a refraction BSDF and a glossy BSDF.

Some quick example renders (the darker is refraction):

You can see the similarities in that the Glass shader is the refraction shader with some more bits added. Note the weird black artefacts in the Refraction BSDF, whereas the Glass BSDF has the rays bounce off the interior more realistically. For an even more realistic shader, you would want to mix a Refraction with Glossy BSDF - the Glass BSDF is just intended to be easy to use and do what the name says, AFAIK. (Edit: a glass BSDF is extremely similar, or possibly identical, to a refraction BSDF mixed with a glossy BSDF with the factor set to a fresnel node. The fresnel node returns values based on the angle of the surface to the camera. If you want to simulate glass and have more control over these kinds of things, this might be a better setup, although if you're just beginning to use Cycles then glass should do for now.)

Here's a picture showing two cubes with those two different materials applied, but with the same final result (one is a Refraction BSDF mixed with a Glossy with a Fresnel node as the factor, the other is a Glass BSDF):

If I had set up the scene better and put another object next to the cube you would see it reflecting off the glass BSDF but not off the refraction.

I can't offer an explanation for the black bits in the Refraction BSDF, but I suspect it has something to do with the way the renderer processes internal light bounces. Edit: I believe that the refraction BSDF is casting a shadow on itself.

TL;DR (for those of you with really small screens): A glass BSDF is a refraction BSDF plus reflection.


Mesh modeling and shad smooth results This is a sword pommel I am modeling.  Last part of the sword and it will be done as my fist modeling test in blender.

As you can see I tried my best to keep the mesh as simple as possible.  In order to have a good smooth result.

Then why am I getting this when I add a simple smooth shade?

If I try a multiresolution, subdivide or smooth modifiers it is even worse with the whole mesh messing up terribly the more I add on the modifiers.  WHY?

I have a file upload here for you to check.  It is the pomel and the crossguard of the sword on which both I used a mirror modifier.  Guessing is the source fo the problem.

I think I have solved the problem by first perfecting the mesh a bit then cutting the mesh in half on the side which best was effected by the shade smooth and added a mirror modifier.  Still, I would love to understand normals a bit more especially what is the difference between the red and blue?

Your mesh has some modeling issues :).
I'll talk only about your Pommel object here.

01) Lots of N-gons
N-gons (faces with more than 4 sides) don't work well with shading or Subdivision modifier.
It's better to use quads and tris.

You original mesh left, repaired right

02) Overlapping geometry
This is a big problem in 3D modelling.
You have double edges, vertices and faces.
Some can be cleaned up by Mesh->Clean up->Merge by distance, but others have to be cleaned manually.

03) Flipped normals
Normals show which way a polygon is facing. If they're not facing the same way, it causes problems with shading and Subdivision.

You can check your normals here.
Blue should be facing out, red should be facing in.

To fix all, select your whole mesh and go to Mesh->Normals->Recalculate outside.

Additional issues:
Your origin point isn't in the center - it's a tiny bit to the side.
This causes problems with the Mirror modifier.

Other tips for your workflow:
Set your units to milimeters for better precision.
Use orthographic view - it will help you be more precise.
Enable absolute grid snap - it will snap precisely to your grid.
Mirror modifier has a Clipping option - use it.

You're doing great so far, don't feel discouraged.
Good luck with your model, you're on the right track :).

Here is the repaired file:


BGE get controller/joystick count in python I am making bge games and want them full controller support and I have already scripted the input, but the axis and the buttons index is changing when having different amount of controllers. Here is what I mean:

#joystick for buttons, joystickaxis for axis

#2 controller

#controller 1
joystick = bge.logic.joysticks[0]
joystickaxis = bge.logic.joysticks[1]

#controller 2
joystick = bge.logic.joysticks[1]
joystickaxis = bge.logic.joysticks[0]

#4 controller

#controller 4
joystick = bge.logic.joysticks[3]
joystickaxis = bge.logic.joysticks[0]
#controller 3
joystick = bge.logic.joysticks[2]
joystickaxis = bge.logic.joysticks[1]
#controller 2
joystick = bge.logic.joysticks[1]
joystickaxis = bge.logic.joysticks[2]
#controller 2
joystick = bge.logic.joysticks[0]
joystickaxis = bge.logic.joysticks[3]

#3 controller

#controller 3
joystick = bge.logic.joysticks[2]
joystickaxis = bge.logic.joysticks[0]
#controller 2
joystick = bge.logic.joysticks[1]
joystickaxis = bge.logic.joysticks[1]
#controller 1
joystick = bge.logic.joysticks[0]
joystickaxis = bge.logic.joysticks[2]

#1 controller

joystick = bge.logic.joysticks[0]
joystickaxis = bge.logic.joysticks[0]

Now I need my script to know how many controllers are registered in bge and I would like to know if there is a python function for that, I mean bge seems at least to know how many there are.

bge.logic.joysticks gives a list of the max number of controllers (eight), now if there is not a controller the list will have None in that slot.

All you need to do is count how many not None items are in that list, or what I did, count how many are None.

connected_controllers  = 8 - bge.logic.joysticks.count(None)

Since we know there are always eight controller slots, it counts how many are "None" and subtracts that from 8. Quite simple really.


How to scale dimensions of a model while keeping the other dimensions proportional ?? I want to make my model "4cm" in order to be able to 3D print the model. I've applied the scale of my model, and I am trying to change the dimensions of the Y-AXIS from 11.817 m to 4cm, while the other X and Z axis scale proportionally.
But, I the X and Z dimensions don't scale to their proportional sizes to the Y-Axis of 4cm, and turn into X:0 and Z:0 .
Is there anything im doing wrong? or another way?

Here are the steps you could follow:

Select your model in Object mode, Hit CtrlA
Hit S and start scaling.
Scale close to the value you want, and then hold the Shift to fine tune the scaling as you move your mouse.
LMB to complete the scaling operation.


How do I split a movie file in Blender? How do I split a movie file into parts in Blender 2.76b?

Imho, just seeing how many answers and comments you got, should say something about why more detail are needed :) but, since currently the blender manual seems to be somehow missing examples and more details, let's see if this helps:

You can split ANY strip in the Blender Video Editor (VSE), when the cursor (current frame) is over it, but in two different ways: "hard cut" and "soft cut". This also applies to video (movie) strips.

"hard cut" means that the the strip will be separated in the cursor point in two smaller clips, that became then independent, and each has only the strip frames that the cut left to it, depending on the cursor position.

Then, you can move each strip even to other channels, but if you try to extend (dragging the side triangle handle) the smaller strips toward the "now missing" part of the movie, while possible, will show nothing more, of course, since the missing frames are now gone, and the strip background will be accordingly drawn transparent:

(using the transparent part in your edit will render a "frame freezing" effect - showing last possible frame from that side of strip - on the left side it will bethe first possible frame, on the right side it will be the last possible frame)

"soft cut" means that the the strip will be still separated in the cursor point in two smaller clips, that became then independent, and they will appear identical to the "hard cut"...

...BUT, while each will appear trimmed to only the strip frames that the cut left to it, depending on the cursor position, as in the "hard" cut, they will instead "keep" also the "missing" frames, just hidden (the strip has really been duplicated and both copies trimmed to show just what was expected by the cut position).

And when you drag their ends towards the "missing" part,

The "missing" frame are still there, and they reappear! So, in a sense is a less definitive cut, and you can still change your mind later, or use the same portion of the original video in boths strips, if you need.

(of course if you extend beyond original length, you will get the usual effect of frame frezing from then on, as in the "hard" cut)

I hope this answers your question :)


Fire collision object I am working in EEVEE and I set up a fire simulation. I am trying to figure out though, is there a way to have my fire wrap around an object? I need it to collide with what is above it and wrap around the sides...

This is a standard task:

add to your scene (domain and flow) one FLUID of type "EFFECTOR"
simulate and check if the result is ok

Please keep in mind that a plane as "EFFECTOR" could not be correctly read by the simulation engine. Go with a cube or similar to be sure the simulation works.


I added some legs to a Blender model and now the bones do not move the mesh, what did I do? So this is the first time I've done this in Blender opposed to using PMX Editor. I wanted a model to have legs and a skirt instead of the jeans she originally had so I added them and removed the bones that came with the legs. I have deleted the extra vertex groups it created and now none of the bones work.

How do I go about fixing this? I have included the Blender file. Any help would be absolutely amazing.

Answered by @batFINGER.

  Try turning manipulate center points off. – batFINGER


How do I get objects to follow another mesh? I have a "book" mesh that is rigged and sample objects on the surface.  When the book opens, I want the spheres to follow and keep their current location.  The only way this works is if I make the spheres part of the same mesh, which I do not want to do. I also don't want the spheres to be part of the same amature as the book.  They will have their own amatures. I want them to remain in their static location when the book opens.  Is there a way to keep the spheres at the static locations on image 2?
Is there a trick using empties?

You can parent your balls to a vertex or to some vertices of your plane: Select a ball, shift select the plane, go in Edit mode, select a vertex or some vertices and press CtrlP > Make Vertex Parent.


What does the button next to the Pivot Point button do? In the 3D view port's header, what does the button next to the Pivot Point button do? The button in question has a shortcut of alt ,. It is in the red square in the picture below.

What is it use for and how is it used?

That button  is the manipulate center points option, which allows you to manipulate the origins of objects without affecting the rotation and scale of the objects themselves.

For example, if I scale these objects without it enabled, they are stretched. With it enabled, only the origins are moved (only affecting object location):

Note that with only one object selected, enabling this option will cause scaling or rotating the object to do nothing.


How to attach eye armature to rigify armature? Im creating a character, and Im using a rigify armature for the body. and a normal armature for the eyes, I used a Keep offset setting to parent the eye´s armature to the rigify armature, but when I move the head bone the eyes blows up!

Rigify armature is really confusing with all those names so what I always do to parent head with new bones for the eyes is to select head bone in edit mode, add a new bone and then add other bone that is going to move one eye and then do the same for the other eye.

After that select the bone that is in the middle connecting eyes with head and delete it. You will have eyes parented with the correct bone head.

I know there are probably other way to do that


Why does render resolution affect RAM use? I am trying to understand all the factors that effect RAM use so I can get the most out of my graphics cards VRAM when rendering. I understand that the amount of geometry and the resolution of textures make a big difference. However, I do not understand why render resolution does. Can anyone explain why?

The image that is rendered need to go in the ram, so bigger image need more ram, have a look here: View Memory Usage There are other points like adaptive subdiv, but I'm not a specialist of these kind of questions.


How to draw a slider button with a custom defined numeric value? The following code generates this UI:

    row = layout.row()
    row.prop(mesh, "use_auto_smooth", text="BreakEdge")
    row.active = mesh.use_auto_smooth and not mesh.has_custom_normals
    row.prop(mesh, "auto_smooth_angle", text="Angle")

This pretty much replicates the generic Blender Mesh Data panel.

What I would like to do is set the 180 by default to something like 30 which is more common for hard edge modeling than 180 to break an edge.

Would something like this even be possible overwriting the custom value I would like to begin with?

I don't know if it is possible to set the default auto_smooth_angle of each new Mesh object -- I think your reason for trying is legitimate. If it isn't possible there's an alternative you might be interested in.

Rather than changing a default property of a mesh's auto_smooth_angle a solution could be to offer an EnumProperty with some quick-pick options, in addition to the existing slider. The enum would update the slider when an option is selected, if you want to fine tune then you use the slider.

here the rough code:

import bpy
import math
from math import radians

class LayoutDemoPanel(bpy.types.Panel):
    """Creates a Panel in the scene context of the properties editor"""
    bl_label = "Layout Demo"
    bl_idname = "SCENE_PT_layout"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "scene"

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

        obj = context.active_object
        if obj and obj.data:
            mesh = obj.data
        else:
            return

        row = layout.row(align=True)
        row.prop(mesh, "use_auto_smooth", text="BreakEdge")
        row = layout.row(align=True)
        row.active = mesh.use_auto_smooth and not mesh.has_custom_normals
        row.prop(mesh, "claas_smooth_angle", expand=True)
        row.prop(mesh, "auto_smooth_angle", text="")

def register():

    def set_smooth_shade_angle(self, context):
        obj = context.active_object
        if obj and obj.data and obj.type=="MESH":
            mesh = obj.data
            mesh.auto_smooth_angle = radians(int(self.claas_smooth_angle))

    bpy.types.Mesh.claas_smooth_angle = bpy.props.EnumProperty(
        items=[(str(j), str(j), "", i) for i, j in enumerate([30, 45, 90])],
        default="30",
        update=set_smooth_shade_angle)

    bpy.utils.register_class(LayoutDemoPanel)

def unregister():
    bpy.utils.unregister_class(LayoutDemoPanel)
    del bpy.types.Mesh.claas_smooth_angle

if __name__ == "__main__":
    register()

or

    row = layout.row(align=True)
    row.prop(mesh, "use_auto_smooth", text="BreakEdge")
    row = layout.row()
    row.active = mesh.use_auto_smooth and not mesh.has_custom_normals
    split = row.split(percentage=0.4)
    row = split.row()
    row.prop(mesh, "claas_smooth_angle", expand=True)
    split = split.split()
    row = split.row()
    row.prop(mesh, "auto_smooth_angle", text="")


Weird reflection in final render I've been going through the blender guru's 2.8 neon tutorial, and the result was looking alright, but in the final render a weird reflection appeared.

My brick texture is nonreflective, but this doesn't even seem like a normal reflection regardless. Even weirder, the reflection does not show up in the rendered view of the viewport, so I had no idea this was going to happen.

Does anyone have any idea what could be causing this?

This looks more like an object than a reflection to me, my guess without seeing your file is that you have an object hidden in viewport yet set to visible in the render.


Why duplication not follow path Im making duplication along the path. I have a mesh and a curve path. Selecting the mesh and curve i press Ctrl+P and selected follow path. In Duplication i turn off speed. The mesh is not following the path in circular shape. Its twisted. I applied scale and rotation to both curve and mesh yet the result is twisted. Any suggestion or help.

dupli error file

I tried your file, and just after removing the parent in "object > relations" and selecting again "cube.004" in that listbox, the parent is better:

something didn't update correctly during some previous operation, maybe.

edit: ok, it is nearly the same even with the new file.

this time, after re-applying the parent as above, you need to clear its origin.


Is Blender the right software to make 3D animations of Mechanical components and assembly? A complete newbie of the field here. Apologies in advance if this is basic question.

I am trying to figure out what software is capable of producing something like this: https://www.youtube.com/watch?v=leosVYDGb-Q

Would Blender be able to do that?

Thanks again,
PG

If you are looking for an actual force driven physics based simulation, Blender can be limited in that area and is probably not adequate for what you are seeking.

Bullet, the physics engine behind Blender is quite capable but not very suited for mechanical workings, and tight fittings and chained interactions like mechanical parts do not work well there and glitch out very easily.

On the other hand, if you don't mind a geometry/maths based solution, then Blender it sounds right for you, and Blender should be perfectly able to do what you see in the video. If you are looking for illustrations of mechanical parts and animations of simulations the constrains system should be quite adequate and easy to set up.

You may want to look into constraints based animations tutorials
See:

Precise Mechanical Rigging (Intuitive method)
How to animate winding a ribbon onto a cylinder?
Rigging an umbrella-like object
Is Blender a sensible environment for making a first-person orrery?


How to scale a texture so it appears smaller or larger on an object, during texture painting? How can I change the texture to make it appear smaller on objects, or larger?

From the way your question is worded, I think you want to scale the UVmap in the image editor.

Select your entire UVmap in the image editor, and scale it. a larger UV map will make the texture appear smaller and more repetitive, and a smaller UVmap will make the texture appear larger (and lower resolution)


Curve modifer has unusual inversion I'm trying to deform a "chain" to follow a NURBS curve, but there's a weird inversion at the bottom of the loop.

I've tried various applies, scales, subdivisions, but the basic issue remains.

Thanks for any insights, I'm stumped.

As suggested in answer to this question that 'stacker' pointed me to below, I did indeed manage to fix this by ensuring the curve and target geometry shared the same origin.


Symmetrize Rig / Bones Issue I'm running into an issue with symmetrize where it is successfully mirroring bones, but across the wrong pivot. My expectation was that it would mirror the bones over the main axis rather than around the pivot of one specific bone. Any idea what might be happening and how I can fix it? Attached are a few screenshots. Thanks for your help in advance!

try select all you want to simetrize and with right button chose "names" > left-right, and what you don't want to simetrize and choose "names" > top-bottom. So select the left-right bones and simetrize will use the top-bottom bones as reference.


Can I make 3D spheres to deform/pulse in sync with audio? How can I make a sphere-like object pulsate with the beat of a song? Is this possible to do in Blender, or do I need to get Adobe After Effects?

Here is an example of what I mean:
https://www.youtube.com/channel/UC_aEa8K-EOJ3D6gOs7HcyNg

I had so much fun re-creating this effect that I ended up doing it twice. You can see the final results (with sound) here.

Unfortunately a step-by-step guide to creating exactly what I made would be a bit long for an answer, so instead I'll summarize the process, with lots of links to other more specific answers.
The basic idea is this:

Create an empty (⇧ ShiftA> Empty) and keyframe an arbitrary transform channel (I) (using an empty's transform makes setting up drivers a little quicker later on)

Use Graph editor > Bake Sound to Fcurve.
If you want to get fancy you can bake several empties (or several transform channels) with different frequency ranges (for example, if you want to change the scale with the amplitude of bass sounds while changing the color with higher pitched sounds)

Use drivers to control whatever settings you want (object scale, subdivision levels, or even cycles materials) based on the empty's baked transform channel.
The reason for baking to an intermediate empty rather than directly to the property you want to animate is solely for ease of tweaking. With a driver you can e.g. use an expression to adjust the amplitude later on, or use multiple drivers to drive multiple properties off of a single empty.

With that in mind, I used a cube with some modifiers to create the sphere:

Subsurf To add more geometry to the cube
Cast To make the subsurfed cube spherical (note the Factor is set to 1)
Displace To produce the actual distortions. The texture used for this modifier is on the top right. The empty used for the texture's coordinate space has a random rotation animation generated with a noise fcurve modifier.
Cast (again) To flatten the displacements back towards a sphere a bit, but not all the way. Note the Factor on this one is < 1
Smooth Just to smooth out annoying wrinkles

Other points of interest in this screenshot:

The material used for the main sphere
The material used for the duplispheres (small dots)
The driver expression used to drive the displacement modifier strength (the referenced empty's Y location is driven by a sound-baked fcurve). To add a little "pep", the raw value is multiplied by 5 (totally arbitrary choice on my part) then taken to the second power. min() provides a quick way to limit the maximum value the driver will produce; e.g. min(somenumber, 1) can only ever return numbers < 1.

To create the dots I duplicated this cube and used dupliverts to render the second cube's vertices as icospheres, and added a driver to the subdivision level on the subsurf modifier.


How do I sanitze? Pose Library: Error: Potentially corrupt library, run 'Sanitze' operator to fix. I deleted some bones that are now keyframed and underlined in red the Action Editor. I assume that is why I have this message:

Potentially corrupt library, run 'Sanitze' operator to fix.

I never sanitized anything in Blender nor do I know where it is or what it does.

I tried hitting Make Actions Suitable that makes 228 poses? so that's not it.

The Sanitize button (and command) did not fix the problem for me.

However, this did:

In Object mode I selected the armature.
I switched to Pose mode, and entire armature was selected.
I hit the spacebar to pull up the command browser, and typed in "pose" to filter the list of commands.
I had tried all the top ones, and it "felt" like I needed to do
something to the "PoseLib" so I chose "PoseLib Add Pose"

The error is now cleared, and I have a Pose Library with a single "Pose" in it.

Blender 2.8 beta


Applying color to a large number of duplicates (Bricks) I modeled a brick. I made an array. I duplicated the array,added the courses to each other, then duplicated that,etc. I'm having trouble figuring how to color them all in one "click".

Select all the objects you want to be the same color then press Ctrl + L  > Make Links > Materials.


hair particles disappear when joining objects I'm making an eyebrow and, with the mesh selected, I have added hair particles with some settings. I have the eye below that. I want it to match with the eye on other side, so I clicked CtrlJ to join. It joined and I got the other eyebrow, but the hair particles disappeared. May i know the reason why it disappeared and how to recover it?

After adding vertex group in density same result

Joining the meshes is making the Particle modifier disappear.
When you join two meshes the active object modifiers are preserved. The active object is the last one you selected, and will be outlined in a lighter orange. In your case you're selecting the eye last, and its modifiers are being preserved, not the eyebrow's ones.
You need to select the eyebrow mesh last, then join.
Also, to avoid hair getting scattered everywhere when you join the meshes do the following before joining:

Select the eyebrow, go into Edit mode.
Select the area that should have hair.
In the Object Data panel, create a new Vertex Group, rename it to your liking and click on "Assign".
In the Particle panel, scroll down to the Vertex Groups and set the vertex group you created as Density.
Now you can leave edit mode and join the meshes.


The Character has in the Blender view no colour!! My character, the man in the screenshot has no color in the 3D view. I marked it with blue color. There is also a UV texture, which I added to [Image Texture]. Does anyone know how to get the color in the 3D view according to the texture?

Please change the Viewport Shading as high lighted below:

To: Texture or Material


Image Alpha Background Renders Black when using “Import Images as Planes” 2.0 This is a question about an old question which can be found here. I also found an answer to that question by Cegaton, though the instruction in the answer didn't help me, and I suspect that it might have only worked for the older version. So I'm using Blender version 2.78, I enabled the "use alpha" and it still doesn't work in any view, I used Gimp2 for the alpha channel and exported it into png, and imported as a plane using the addon, the plane is still a picture with black opaque background.

Screenshots:

Picture in GIMP2

Exporting the picture as Png

Importing the picture as a plane

Choosing the picture

The plane in object-solid view

The plane in object-texture view

An Image for you to test on:
Please note I am not sure if the alpha channel will stay there if you download it please let me know down in the comments.

In your particular case you did not enable

Use alpha:

In newer versions of blender that box might not be there but you can still select to have transparency as you import the image:

The trasnsparency will only show on Material or Render view, it will not be displayed in texture view.

For more details read the previous answer:
Image Alpha Background Renders Black when using "Import Images as Planes"


Creating a 30 degree angle at a corner of a cube I am drawing a greenhouse and must create a 30 degree angle at one end a drawn 2 by 4.

Search to date has not produced an example of creating a precise angle.  I grab and move two opposite vertices on the x axes and an angle is created but how to be precise?

One way to do it numerically, assuming Y up, X across, and starting with the end of your bar square..

CtrlC Copy the height of your bar from its Y in
the Dimensions panel
Select the top edge or point, (whatever will wind up where your arrow is..)
GX, and then in the Adjust Last Operation panel, type into the 'X' field: "CtrlV / tan(pi/6)"

You can stash expressions like this  in a text-block to copy and paste from if you have to do this sort of thing often, but usually you only have to do this once, the rest is duplicates and snapping.


It is distributive if you convert the world matrix to a $3 \times 3$ matrix first or extend the vector by one dimension. The vector needs to have as many elements as the matrix has columns.
>>> x = bpy.data.objects["Camera"].matrix_world.to_3x3() @ (top_verts[1] - top_verts[0])
>>> x
Vector((1.0669403076171875, 1.1318906545639038, 0.0))

>>> y = bpy.data.objects["Camera"].matrix_world.to_3x3() @ top_verts[1] - bpy.data.objects["Camera"].matrix_world.to_3x3() @ top_verts[0]
>>> y
Vector((1.0669403076171875, 1.1318907737731934, 0.0))

Generally it is not possible to multiply a $4 \times 4$ matrix with a $3 \times 1$ vector, because the dimensions don't match. Blender tries to be smart and extends the dimension of the vector by adding elements with value $1.0$ when necessary. However, since this is only done when the multiplication is performed, it is no longer distributive:
$M \times \left(\overrightarrow{v} + \overrightarrow{v}\right)_{extended} \neq M \times \overrightarrow{v_{extended}} + M \times \overrightarrow{v_{extended}}$
The reason for the difference is that Blender can perform the addition $\overrightarrow{v} + \overrightarrow{v}$ without extending the individual vectors. The element is only added afterwards when the multiplications with $M$ is performed. In comparison, $M \times \overrightarrow{v_{extended}} + M \times \overrightarrow{v_{extended}}$ requires to extend both vectors right away. The results are not equal since in the former case the vector should have been extended prior to the addition, resulting in a fourth element of value $2.0$. However, Blender performs the extension afterwards with an element of value $1.0$.
Blender tries to help the developer, perhaps a bit too much in this case, thus masking the error of wrong dimensions. This is especially hard to see since the output is truncated to the size of the original vector.


How can I create a new object in the Outliner? How can I create a new object in the Outliner?
I'm using Blender for the first time and im watching this tutorial video.
https://www.youtube.com/watch?v=v_X9v29i-Iw
As you can see in 1:16 min in the video, the guy adds a cylinder.

If I add this cylinder, it doesn't appear as a new object in the outliner.

It's a problem because I used the Subdivision Surface tool on the body
The cylinder that I add there has the subdivision surface tool as well then... and it's not a cylinder anymore...

If I want to remove the subdivision tool, the body doesn't have it either then.

You have to be careful in witch mode you add a new object. If you are in object mode you add the new mesh as its own object and you can see it in the outliner as its own item with its own modifiers, etc. but if you are in edit mode inside another object and you add the new mesh in edit mode it becomes part of the geometry of the object you are in edit mode of sharing that objects texture, modifiers, etc.


Image setting in UV Project Modifier I'm trying to understand the use of the "Image" option and how it works with the "Override" box on the UV Project Modifier. I'm using this file to test.

(there is a scene for BLender Internal and one for Cycles)

Is there a setting I'm overlooking?

Blender Internal

If I select an image on the modifier, and click the "Override Image" box, the selected image will only get displayed on the object if "Multitexture" Shading is enabled. If I hit render I get the original texture, not the one projected by the modifier (even if the box is checked in the material->Options->UV Project) The original texture is indeed using the projector's coordinates.

Multitexture

In GLSL shading the Image option has no effect: the selected image never gets displayed projected over, and the object keeps its original texture regardless of the state of the Override box.

Cycles

Here the image setting has no visible effect either .

In any case, I can't make the image selected on the modifier show up for preview or in the final render, even if the modifier is applied... So what is the purpose of selecting an image in this box?

So what actually the UV Project modifier does is only manipulates UV coordinates. Without an UV map it won't work. The Override option will work only in Multitexture, it can't override material textures, only textures displayed on mesh faces.

All the stuff about view-port visibility and what renders is nor related to this modifier but rather to how blender works.

Multi-texture Blender Internal:

In view-port Blender is able to preview textures without any materials applied - just the ones in the UV/Image editor. In render it uses materials. That's why view-port and render differs. The UV mapping is altered with the UV Project modifier - it is altered for both render and view-port.
Cycles and GLSL Blender Internal:

In view-port Blender previews material textures. If a texture is not in a material, you can't see it on the model.

For Blender Internal materials there is UV Project option to ensure correct UV interpolation for UV Project modifier. For both GLSL and Cycles the material mapping should be UV:

If you setup a material for Multitexture the same way like for GLSL it will work in render.

Everything is correct in your .blend, it's just that you expected the UV Project modifier to override material textures, which is not the case, and you need to use the "AB" texture instead of "B" in your shaders.


Render is completely transparent I've checked the active camera, there's nothing in the sequence editor, I've tried everything and cannot figure out what I broke.

I literally just want it to render out how it looks in the viewport a Smoking crashed spaceship against a green screen. But for some reason, the render is blank, and then also it puts the video clip from the motion track on it too, which I don't want it to do either but that's a different issue.

Viewport:

Node tree:

Notice how the initial render is completely blank...?

The issue you are having is that the layers you have set your Render Layers to are completely blank in front of the camera. You need to add the correct layers in your Render Layers settings.

The reason this was rendering in the viewport, is you had all of the layers selected to display in your viewport, while those layers were not enabled in the final render.

You may want to disable the compositing stage to get ride of the video overlay :

to keep the compositing and just eliminate the video overlay change the compositing nodes as this :


Can't use Boolean Intersect on two meshes I'll tell you the whole deal so maybe you can help me with ideas at different points.

First. I generated a terrain using Sketchup and the Location tool. I had to use a bigger section than what it was possible at 1 time, so i used many (20 or so) terrains and "stitched" them together

Second. I imported everything to Blender as a collada file.

Now. In Blender, i need to make a section to one of the mountains to show (in a later animation) what's going on inside it.... and that's what have been impossible.

I've tried to simply "boolean" it with a plane. and the operation can't be executed... I admit i'm a total newbie... but i thought i should work....

If this is not the proper way to do something as simple as this, can anyone tell how would you do it?

So, after tryin to put in practice the solutions you kindly lend to me, i keep having a problem.
My favorite solution is with the bisect tool... but i can't find a way to keep both halves in a clean way after the bisection.

Here's an useful question, but i couldn't put into practice, apparently because I'm using a mac and the latest version of Blender, so the commands were not the same... maybe you could help me "translating" those commands.

You need a manifold (watertight) mesh for the boolean operation to work. Try replacing the plane with a cube:

Another option is the Bisect tool:

In edit mode, press Bisect in Tool Shelf (N) > Add:

Then draw the bisection line with LMB and drag:

Enable Clear inner or Clear outer (in the Redo menu at the bottom of the Tool shelf, or the F6 menu) to remove one side of the mesh as defined by the bisection line (also enable Fill to fill the hole):

If you want to keep both sides of the bisect cut as separate objects, you could try either of the following:

Manually separating the bisected parts of the model:

Bisect the mesh without enabling Fill or either Clear option, so it only makes a cut down the bisection line (the same as if you had used the knife tool):

Select one side of the mesh with Select Loop Inner-Region in 3D view > Header > Select > Select Loop Inner-Region:

Press PSeparate > Selection:

This will give you two objects, one for each side of the bisect operation.

To fill in the hole, you could select the edge loop on the very edge with AltRMB and fill (F), however if the bisect line goes across any interfering geometry this will not work. (This might also be too limited for meshes that have an internal structure)

Or you could duplicate the mesh and run two bisect operations, one on each.

Bisect one mesh and enable Fill and Clear Inner.
Pull down the info window and scroll to the bottom. You should see a line which begins like this:

 bpy.ops.mesh.bisect(

Select it with RMB and press CtrlC to copy it:

Select your duplicate mesh and enter edit mode (Tab).
Split a new area, set the editor type to Python Console and paste the selected line. Note that you may need to add use_fill=True, and clear_outer=True, in between the parenthesis ().
Press Enter. The mesh should be automatically bisected identically, except the opposite side is cleared.

Note that you can also set the exact coordinates from the UI:

So if you wanted to manually copy each value from one operation to the other, that would be another way.


Render looks "brighter" than in viewport preview Somehow my viewport preview shows darker result than what comes out in render (check out in corner of the pic)

World strength is at zero and ambient occlusion is also disabled.

Floor is using bump and roughness from picture. Wall has adaptive subdivision surface  modifier.

All lit using planes with emission shaders.

I wanted to play around with render layers and maybe I screw some setting there, hope this helps.

Look at your outliner, you have (at least) 1 object (probably a light) set to render, but hidden in viewport (camera icon active, but eyeball icon greyed out) it's named BMWRim .  I'm guessing it's a rim light.


Button callback based on the objects particle system? I have button in my panel, that button switch emitter/hair in particle system
it works, but the problem is i have many object, and if i change object selected, button not update.I'm looking for a correct method. This sctipt is simplified
for explain:

import bpy
from bpy.props import  BoolProperty
from bpy.types import PropertyGroup, Panel, Scene

def UpdateMitter(self,context):

    toogle = bpy.context.scene.my_prop_grp.emitter_hair
    obj = bpy.context.active_object
    part = obj.particle_systems[0]
    settings = part.settings

    if toogle is True:
        settings.type = 'EMITTER'
    else:
        settings.type = 'HAIR'

class PropGroup(bpy.types.PropertyGroup):
    emitter_hair: BoolProperty(update = UpdateMitter)

class MyPanel(bpy.types.Panel):
    bl_label = "My Panel"
    bl_idname = "test_toogle"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_category = "View"

    def draw(self, context):
        layout = self.layout
        layout.label(text="My problem:")
        scene = bpy.context.scene
        layout.prop(scene.my_prop_grp, 'emitter_hair',  text="Toggle")

classes = (PropGroup, Panel)

def register():

    bpy.utils.register_class(PropGroup)
    bpy.utils.register_class(MyPanel)

    Scene.my_prop_grp = bpy.props.PointerProperty(type=PropGroup)

def unregister():

    bpy.utils.register_class(PropGroup)
    bpy.utils.register_class(MyPanel)

if __name__ == "__main__":
    register()

An Object property?

Make it an object property then it is set on a per object basis.

Since the property is defined on an Object class, then self in an update method is an object of type bpy.types.Object of which context.object is an instance .  If it was registered as a scene property, self would be a scene.

If it were a scene property, I would set the PS type for all objects with it.

def emitter_update(self, context):
    toogle = self.my_prop_grp.emitter_hair
    pobs = [o for o in self.objects if len(o.particle_systems)]
    for ob in pobs:
        part = ob.particle_systems[0]
        settings = part.settings
        settings.type = 'EMITTER' if toogle else 'HAIR'

Consult blender docs re naming conventions for classes, methods.

One of my pet hates: when context is passed as a function argument .. use it. Get out of the habit of bpy.context.foo.blah.bar...

Added a poll method in panel so it doesn't show when context object has no particle system.

import bpy
from bpy.props import  BoolProperty, PointerProperty
from bpy.types import PropertyGroup, Panel, Object

def emitter_update(self, context):
    toogle = self.my_prop_grp.emitter_hair
    part = self.particle_systems[0]
    settings = part.settings
    settings.type = 'EMITTER' if toogle else 'HAIR'

class MyParticleSettings(bpy.types.PropertyGroup):
    emitter_hair: BoolProperty(update = emitter_update)

class VIEW3D_PT_toggle_ps(Panel):
    """Test"""

    bl_label = "My Panel"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_category = "View"

    @classmethod
    def poll(self, context):
        ob = context.object
        return ob and len(ob.particle_systems)

    def draw(self, context):
        ob = context.object
        layout = self.layout
        layout.label(text="My problem:")
        layout.prop(ob.my_particle_settings, 'emitter_hair',  text="Toggle")

classes = (MyParticleSettings,
        VIEW3D_PT_toggle_ps)

def register():
    for cls in classes:
        bpy.utils.register_class(cls)

    Object.my_particle_settings = PointerProperty(type=MyParticleSettings)

def unregister():
    for cls in reversed(classes):
        bpy.utils.unregister_class(cls)

if __name__ == "__main__":
    register()

I imagine this will be extended, otherwise could simply put the enum in layout

row.prop(part, "type", expand=True)

or a window manager context toggle operator.

TIP.

In version 2.7x could reload scripts using the F8 key. It is  AFAIK not mapped to a key in default 2.8.

Either map it to a key, run in python console.

bpy.ops.script.reload()

Pre(ap)ending a simple operator button draw method to headers of both text editor and python console provides a couple of handy and often used buttons

For example when testing above, posted with ob.my_prop_group in the draw method after it had been renamed to ob.my_particle_settings.  As I hadn't reloaded scripts it was still registered from a previous test run, and worked as expected.

Running after reloading scripts will throw errors for such unregistered props.


Blender UI Manipulation Python I have a couple of questions:

is it possible to change the color of a single button via python?(like the “add Driver” Operator does)
is it possible to change original blender buttons to execute something else(without changing the source .py ui file). Specifically: Then the user hits the render button, I want to trigger another function and stop the rendering.

No
No cleanly, you can re-define the classes from source .py ui files in your addon. Which is dirty.


Why is my smoke in such a bad quality (cycles)? For a university project I'm working on a 3D scene. Most of it is finished, if I render it with cycles everything is alright except the waterfall. It looks like I rendered it in a really bad quality. I made the waterfall with a smoke simulation at an extra renderlayer with an extra lamp, because in the normal scene it will look pitch black.

Thank you :)

You simply don't have enough resolution. You have 50 base res, and 1x high res. Each high res division splits the voxel along each axis, so with 1x high res your domain container is only 100 voxels high. However, the smoke region alone is over 400 screen pixels high in the final render! Usually there's some padding in the container as well, so each voxel has to cove 4-6 screen pixels! This leads to the pixelated look. You need to just increase resolution.

Adjusting base resolution can alter the movement of the simulation, so try just cranking up high res first. Increase high-res divisions to 3 or 4, and re-bake. See if you like the result. If it looks too obviously like a smoothed low-res sim, drop back to high-res 1 (to save baking time) and do some tests with higher base res, like 70-100. Once you're happy there, bring high res back up to keep even more detail.


How can I see which edge connects to which when UV mapping? In Maya, when UV mapping it will show the selected edge and the edge it connects to on the 3d model in the same colour so you know which edges can be welded together. How can I see this in blender?

You have 2 options in the UV editor, I guess you're looking for one of those:

Keep UV and object mesh in sync.
Automatically select the shared vertices.

You need to deactivate the first option to have access to the second. The first option keep a link between selected vertices in the 3D view mesh and the UV map selected vertices, second one only concerns the UV maps, but I maybe both will give what you want.


How to hide unused Node socket using python script I can manually hide unused node sockets by pressing Ctrl  H, but I wanted to know how to hide an unused node socket using a script I saw a previously asked question about this topic - How can I hide unused node sockets?
in the answers, VRm answered that Hide attribute can do this but hide attribute can just collapse the node itself like when we press 'H.

You can either call hide.socket_toggle() operator on all nodes in selection or hide each socket one by one using NodeSocket.hide property. Following demo is based on Operator Node template:

import bpy

def main(operator, context):
    node_selected = context.selected_nodes

    if node_selected:
        bpy.ops.node.hide_socket_toggle()
    else:
        operator.report({'ERROR'}, "Nothing selected")
        return

class NODE_OT_Operator(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "node.simple_operator"
    bl_label = "Hide Node Sockets Operator"

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

    def execute(self, context):
        main(self, context)
        return {'FINISHED'}

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

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

if __name__ == "__main__":
    register()

Result of calling the operator on all selected nodes in the shader editor

Result of calling the operator on all selected nodes in the compositor

Demo on how to hide the alpha sockets of Render Layer and Composite node using the console:

>>> rl_node = C.scene.node_tree.nodes.get('Render Layers')
>>> alpha_socket = rl_node.outputs.get("Alpha")
>>> alpha_socket.hide = True
>>>
>>> comp_node = C.scene.node_tree.nodes.get('Composite')
>>> alpha_socket = comp_node.inputs.get("Alpha")
>>> alpha_socket.hide = True

Result of setting the state for each output or input socket


How can I create Textured Outlines? I am working on a model that is a 2D to 3D remake and I'm almost done. I just need to get the outline in. I want it to turn in space so I didn't draw it into the texture.

Most outline solutions I have found don't work with what I am going for. Does anyone know how I can get a textured outline like the one in the reference?

Original by crayonchewer: https://twitter.com/crayonchewer?lang=en

Well, you have a few options.

Freestyle creates a line around the edge of all your objects soon render. You may be able to tweak the settings to create the chalk like effect.

Grease pencil is also another option. Can be harder to accomplish but you have more control over the lines.

The last option I have is to use a flat plane and tweak texture settings with clouds to create a brush like stroke. Again, difficult and a hassle but could produce some great effects.

If you want any help on how these may be completed I will try and help where I can.

Torus Test:

EDIT:

This is how I created the torus effect above as requested.

Firstly, create a copy of your item slightly larger than your original. The gap between the two will determine the size of your outline.

Create a circle with the triangle fan fill. The number of vertices is your choice, the higher the count, the better the effect will be but performance will be reduced later. I used 128 for mine.

Go to edit mode.

Select the edge ring and delete all the edges, leaving lines spraying from the centre vertex.

Select everything and extrude to create a pretty cool looking mesh.

Select the centre edge (Done by selecting the two centre vertices) and go to Edge-->Edge Split.

Go back to Object mode

This is where thing may get slow for a bit!!

Add a Solidify modifier and set the thickness really low. I set mine to 0.001.

Add a boolean modifier set to intersect. Choose your slightly larger, copied object for the boolean modifier object. Hide your copy object

Now you should see lots of thin lines around the outside of your mesh as shown below. note as they rotate around they get thinner and disappear.

On my torus, I did not need to do this step for this rotation, but if the centre vertex is showing all clustered together on your meshes surface like below, add a subsurf modifier to the top of your modifiers and set it to 1. this should leave a bit of a hole where the vertex was. BUT DONT WORRY!!! we will fix that soon.

More LAG Ahead!!!

Copy your outline object and duplicate it. Rotate it 90˚ on one of the other two axis' so the lines face in a different direction. Note the small hole on the righthand side due to the subsurf modifier. This will be better hidden with the textures. I do have a small glitch (The plane protruding from my mesh) but it is almost unrecognisable in the render. plus you can delete it once modifiers are applied.

Hide both of these outlines for now if lag is getting the better of your machine :D

Time for a material. I have taken an image of mine below. if you wanted you could use a texture, but I have gone for a procedural noise texture.

Show your two items again and apply the material. Take a look around in render view. My nodes are set for cycles, so some tweaking may be needed to use in EEVEE.

If you are happy with the results, apply your modifiers IN ORDER!!! and you will get your results in mesh!!

This works by the layering of faces adding their translucency to each other slowly darkening the view. The more layers overlapping, the darker the edge. This does create a little bit of darkening towards the center but when set low like mine it is relitively unoticable.

TADA!

Note that I did this on an early 2015 MacBook air which has relatively low computing power compared to many 3D designers laptops and common desktop PC's. My computer started running quite slow when using the boolean modifier caping my limitations but you may be able to take the number of verticies up in your model.

Good luck with your project and I hope I helped.

BFB


Keyframed animation into path animation I have got an animated object that is an opening door. I keyframed the movements; not rig there. Now I want to get rid of the keyframes and create an animation path that does just the same but without the keyframes. Is that even possible? I am not that skilled with animation nor do I know what is possible and what not. Hope someone can clearify this for me. I want to use this created path for the BGE and apply it (on the relative movement from the local space on) to more doors later on, so that I can use it in a python command later on (to toggle the door opening). I know this might be an advanced question, but I thought why not ask. If it's too demanding I will ask out of this forum, though, so that I don't bother anyone with almost doing a tutorial for this.
Thanks for helping.

Your demand sounds a bit strange considering the fact the BGE does not support paths.

You already have an animation. You can simply play it. To play rotation or location animations at different locations ensure the animating parts of the door are parented to a not animating object, such as a static empty.

Sample structure:

base (fixed)

frame (fixed)

wing left (animated)
wing right (animated)

You can align the door by moving and rotating the base object. (Indeed the frame can act as base too).


Getting output socket name and using it for input socket name in compositor i'm trying to do an automated naming system for my file outputs in blender compositor, i want the file output input's socket to get the name of the input of their respective links. I'm not really getting how (new in python). So far my script looks like

import bpy
import os

# Get absolute path:
filepath = bpy.context.scene.render.filepath
absolutepath = bpy.path.abspath(filepath)

# Split it
path = os.path.normpath(absolutepath)
parts = path.split(os.sep)

absolutepath = os.sep.join(parts[:-2])

# Get name of th input
name01 = bpy.data.node_groups["CYCLES MULTIPASS CREATION"].outputs[0].name

# set the path for all file output nodes:
for scene in bpy.data.scenes:
    for node in scene.node_tree.nodes:

        if node.type == 'OUTPUT_FILE':
            node.base_path = absolutepath
            node.file_slots[0].path = "\_shadow\_" + "nom" + "_" + name01

But this is "absolute" version of what i'm trying to do, the input socket name is not relative to the output socket name of the previous node... Somebody has an idea ? thank you very much !

To get the name of the socket a node's input is linked to:

#using the File output node from your example
link = node.inputs[0].links[0] #gets the link from the input
socket_name = link.from_socket.name #returns the name of the socket the link is from


How to setup scene for Isometric workflow? In order to import 2D ISO image to make it in 3D You know we can make 2D isometric renders of 3D images, right? I want to do the reverse; I import an isometric image and want to use it to create the 3D model. An illustration of the work I'm trying to do, I've setup the camera (rotation xyz 60,0,45) and I've created some cubes to work with to see in wireframe:

My problem is, once the correct camera setup is done, the grid isn't set up correctly. I mean that the height of 1 is not corresponding with the grid and the closest I have is 0.81673, you can look the image below. The cubes aren't seized precisely and when I Ctrl+move the increment is 1 and not of the height of the cube;

My questions;

How to find the correct size for my cubes?
How to setup the world to work with that isometric height non equel to 1?
What is the best workflow to achieve the result I want, recreating in 3D a 2D isometric images (moreover if I'm going the wrong way) ?

Thanks in advance

Step 01
Blend file - Dimetry

Set camera Dimetry (54.563/0/45) with dimension of your ISO-image
Increase camera dimension on Y axis *1.150
Add your image as Camera Background Image
Build your models and save

Step 02
Blend file - Isometry

Set camera Isometry (60/0/45)
Add Empty
Link Collection (or Scene) done in Dimetry
Parent link to Empty
Scale Empty on Z axis 0.81673
Render

Like that you can anytime to switch into correctly measured models in Dimetry, but just by opening Isometric file re-render for final output.


Wrap texture evenly around mesh I am trying to wrap this brick texture evenly around this controller 3d model, I can get it evenly around some parts but the handles are causing me problems.

Imaging you are wrapping this object with paper with this print; How would you like the pattern to be cut? There is no magic button for this. You need to UV unwrap it carefully and make decisions about how you want the pattern to be distorted.


Is there a way I can make render times longer to avoid overheating? Whenever I render a picture above 16 samplings with Cycles, my laptop crashes in 5-20 seconds.
Is there a way I can manually make the render time longer while not affecting the quality of the render, so it doesn't get my laptop so hot it self-crashes to not melt itself? (I'm willing to use Add-Ons and, if there is a denoiser that could make a render with 16 samplings look like a render with 128 or 64 samplings that's okay for me as well.)
I live in a very poor country and can't afford a decent PC/laptop. Maximum I can afford is something below 50$ (Which would hurt my wallet quite a lot).

Here is a related SuperUser post.
In Blender, you can lower the number of threads by going to Render Properties -> Performance.

Change from auto-detect and lower the number of threads.
I lowered mine to 2 and started a CPU render and it does appear to split the compute load pretty evenly among the processor cores, so one part of the chip won't necessarily be hotter than the other and it should prevent an overheat.

(This PC runs pretty hot.) :)
It's also worth quickly noting that denoising is a processor intensive task in itself, so it may not be a solution.


How to Track Users of Data Blocks? I find it difficult to understand that there are two users of that mesh data in my blend file.

How can I clearly track the user of a block of data in Blender?

First, deselect all.

You can then select all users of (eg) a mesh by right clicking that mesh in the outliner then clicking "select linked":

It should work with any linked item as materials, etc.

Then if you switch the outliner to "selected", it will list just all linked users.

bring now able to look at your file, it seams really weird...

you have 1 scene, and bender reports 1 object, but in the datablocks you have 188 objects... how many should it have in your goal?

and you "only" object has currently one of dozen other meshes...

could it be that this file has issues due to a "troubled" history..?

I tried appending only this object from your file (all 188 objects are still there) to a blank new file, and it works well now, and its mesh has only 1 real user, as it should have been...


Help with smoothing surface of mesh How do I rid my mesh of its uneven surface. I tried subdividing the mesh, but I'm wondering why the rectangular geometry still persists after so much smoothing.

Give your model Smooth Shading, go to (Tool Shelf) and under Shading section choose Smooth


Run an external application with the bge I have searched about for an actuator that can run external applications within the bge but I haven't found anything. Does such an actuator exist?

In addition, it is possible to launch a web browser within a blender game:
A plane with firefox, chrome... in the game

This task is fairly simple to do with a Python script.

You could add a python script as a controller to launch a browser:

import subprocess
subprocess.call(['pathToChrome\\chrome.exe',
                 'http://blender.stackexchange.com',
                 'Message'])

To save a screenshot you could use one of the command line capturing tools like:

webkit2png
command-line-program-to-create-website-screenshots-on-linux
you might add an os to google "browser screenshot command line"

Once you have the saved screenshot you could manipulate a plane to use the screenshot as a texture see createTexture in Blender API on how to dynamically change a textures image.


Will Warp bridge these two objects? I've read documentation and StackExchange for two days or more and installed 2.74, but I'm still lost.  I watched one Warp tutorial which appeared to do what I wanted, which is to create a bridge between the two objects, but I couldn't duplicate the result.  I got some modification between the end points, but no fill.
The objects which I'm working with present matching planes, but if one were scaled, that would be my next question.  Also, the "curve" option of warp seems to be what I need, but there should also be some rotation to get a smooth transition between the two objects.

https://www.dropbox.com/s/x44ua54ac1pvfnm/warp.blend?dl=0

Thanks for any help.

The 90 degree question and bending pipe didn't answer my question.  @cegaton suggested the following as a possible solution.  This may be the answer, but it may also be beyond my life expectancy to implement.

A problem with Blender's Bridge Edge Loops system

What a comprehensive user friendly program.

The succinct statement of my problem may be: join two faces whose normals don't with a projection of a user shape.
Can curve, bend or warp do that?  I haven't been able to do that, and, from Allen's post, doubt that they can.

In blender there are two Warps.

Warp Tool

The Warp tool pulls selected vertices towards the 3d-cursor. thats it.

Warp Modifier

The Warp modifier, doesn't appear to do what you'd like it to. It will warp in a straight line from A to B.

Tube Tool (can ..sortof)

TubeTool comes closer. Here a a description ( https://blender.stackexchange.com/a/28193/47 ) and here the link to the GitHub repository. Feedback welcome.

TubeTool labours under the assumption (currently) that the selected faces are part of one object. At present that means maybe duplicating them, separating selection and then joining them together into one object. The faint blue line emanating from the faces shows their normal, tube tool allows you to flip the perceived normal by providing an option to specify direction (negative or positive).

This will at the very least give you a nice curve between the two faces, from that point you can select a Bevel Object or reduce the amount of subdivisions in the default bevel circle. The upside to attaching a Bevel Object once the curve is created is that you can adjust the geometry of the Bevel Object to match the two faces.

TubeTool isn't very sophisticated yet, but it could be worth checking anyway - and I'm open to suggestions.


Image texture not showing on object that has UV Map? Following a tutorial, I'm trying to add a Texture to an object via the Texture menu instead of through Materials.
I have Unwrapped 2 different ways (Project From View, Unwrap). I have tried "Render preview" mode.

I'm very confused as to why it doesn't show up on my mesh (But on the Tutorial the image does show up at this point). I have attached screenshots to show my setup. Any ideas, please?

I think what the tutorial left out was, that before painting on your target, you have to assign the resulting (at first probably blank) texture to a material and then switch into a view that supports textured display.
Either solid with textures enabled, Material Preview or Render Preview.

The Texture Properties are supposed to set the image properties before it is used as a brush. It does not effect the resulting texture directly.

Back in Blender 2.7x and before you could assign textures to UVs without using materials. That only worked with BI and could be pretty confusing, so they removed the functionality.
If you have the node wrangler addon enabled, you can have your material nodes open somewhere and CTRL SHIFT click on a texture node to preview it in the viewport.


Displacement ignores UV mapping Here's my problem with applied displacement modifier:

As you can see, when I apply the displacement modifier, the surface is uneven as the texture is streched across every face differently. The only solution so far was to use Remesh on the object, so it divides the whole object to small even squares, but i don't like this solution since my pc runs of out memory.
I've unwrapped the part, and applied it on the displacement. However it does not work!

Here're the settings:

What can I do to have the displacement texture spread evenly across all different-sized faces?
Purpoise is to have this texture on a 3D print.

The part which led me to confusion was using the auto-generated noise texture:

!! Notice the Size: 0.00.
It basically means, the/bumps dots were to be extremely small no matter how many subdivisions i applied. After I increased the size to 0.1, problem was solved:


Loop cut/subdivide triangle I have the top shape. If I subdivide it, I get the second shape. What I want is a way to get the third. I made it by subdividing the two long edges of the triangle, and then knifing between them, but I want a way to automate it.

Two possibilities (at least).

W then subdivide, once the edges are selected: you have to be in edge select mode to do that.

Knife tool (activated by K) then hold the Ctrl key to cut at the middle of the wanted parts (you have to click at each cut you want to position and to validate with Enter at the end)

This last way is certainly more easy. For instance :


bone heat weighting: failed to find solution for one or more bones error message Here it goes again, the rigging error. I have a model that has a mirror modifier already applied and a subsurface and displace modifier (not applied) in my model. So when I try to parent my model to my armature it gets the bone heat error message, but before I applied the mirror modifier it worked, although the bones only work on the left side and the right side didn't work at all.

Solutions I have tried:

Remove doubles (doesn't work)
Recalculate (doesn't work either)
Remove all modifiers (no luck)
Place the root bone at the center of the model (still get the error)
Apply the subsurface modifier and parent them (no result)
Apply the decimate planar modifier (this works, but the decimate modifier destroys my seam marked on my model, which causes my displace modifier to not function well because I baked my displace map with another model that has a multiresolution level of four).

blender file:

I have the unapplied mirror modifier model in layer 3 and applied mirror modifier model in layer 1.

Your trouble shooting is pretty good already. Other useful steps for the future are:

Append the armature datablock and the mesh datablock into a new file. Then create new armature and mesh object and select (link) the appended datablocks. Try it with these clean objects again.
Remove all vertices groups. (There was a group left called "group".)
Remove the UV data.
Remove the constraints on the armature.

None of these get us any further in your case.I also tried to reproduce the problem in a controled environment and failed.
Since it works with the decimate modifier applied, we know it must be a topology error.
As batFINGER suggested you can find non manifold geometry with Select Non Manifold operation (Ctrl+AltShift+M). This will select the the non manifold geometry.
There is non manifold geometry in the tip of the tail.
Most of it doesn't cause any errors though except two vertices.
As you can see in the image, there are to vertices which are connected to overlapping faces. Delete the vertices and Parent > Armature Deform with automatic weights will work.
(Click to enlarge.)


Batch rename shape keys I'm kinda new to blender and can't seem to find any fast way to rename shape keys.

I have found many addons and scripts to batch rename objects but none work on shape keys.

Is there any way to batch rename shape keys of single object or even better to just remove certain letters from all shape keys on given object?

You can use the python api to script functionality, which isn't exposed through UI functions.

Write/Paste scripts in the text editor and press Run Script on the editor's menu bar to execute it.

First we get a list of shape_keys.

import bpy

# get the selected object
selected_object = bpy.context.object

# get its shapekeys
shape_keys = selected_object.data.shape_keys.key_blocks

Next, we can loop through the list and do a replace operation. shape_key.name is a string which stores/gets/sets the shapekeys name.

# loop through shapekeys and replace the names
for key in shape_keys:
    key.name = key.name.replace("Key", "FaceKey")

We could also suffix them with an indice.

# loop through shapekeys and replace the names
for index, key in enumerate(shape_keys):
    if key.name != "Basis":
        key.name = "MyKey" + str(index)

For some reason, the UI doesn't update the names of the shapekeys untill you hover over them.


blender animation not updating in render mode but working in texture mode https://drive.google.com/file/d/0B51VSnCzGPLfdzVLQVYtYngwWDA/view?usp=sharing

I got above blend file from tf3dm , but I find that when I try to change the animation to video I am getting a blank screen.

how to render it such that I could see the animation as a video.

If you open the video sequence editor  you will find an image sequence strip. Blender will render the sequencer with higher priority than the 3d view. The images can't be found, therefore a blank frame is rendered. Disable the Sequencer to ignore the image sequence in the sequencer and to render the 3D View and the Compositing setup.

Uncheck Sequencer in the Render Settings.


How to manipulate Gradient Shader Being kind of new to Blender, Shaders are still kind of a mystery for me, I tried adding a Gradient Shader to the Background in World, to my surprise, I couldn't find any sliders or colors! is there a way to change the default colors in Gradient shader?

The Gradient texture outputs a numerical value between 0 and 1.  You can create a color gradient from this by plugging the gradient texture into a Color Ramp node.

The Color Ramp takes a value between 0 and 1 (values outside this range are clamped) and outputs the color from the proper place along the set gradient.  A value of 0 will output the color on the far left, a value of 1 will output the color on the far right.

You can create a custom gradient by adding color swatches, Cycles interpolates the colors between each swatch.  Add a new color swatch by clicking the "+" button, select a swatch to change its color and position.

As a technical side note, the gradient node is actually a texture not a shader.  A shader is a set of instructions that tell Cycles how light interacts with the surface or volume of an object, a texture is an array of colors.


Rotating / positioning lighting Total noob here,

I am searching the whole internet looking for how to rotate a lamp.

I see several youtube videos showing it being done and saying "rotate lamp ..." How do you rotate a lamp? I can't leave Object mode with the lamp highlighted. I understand that you don't rotate Point lights as they are omnidirectional. You should be able to rotate almost any other lamp. "R" doesn't activate rotation. What am I doing wrong? It seems like it must be the easiest thing to do because nobody has had to answer it before!

Okay, I assume you've figured it out by now, but in Object Mode: look to the bottom left of the screen, you should see a dark grey box, if it says: "Global" click it and select the option that says: "Normal" I just had the same issue as you, but I figured it out. it SHOULD work now.

through looking at your picture, I see that it does say Global.


How can I export the motion tracking markers to csv? The blender motion tracking markers are very convenient to use but it seems there is no direct way to export the path of the markers themselves.

Is there a way to export the paths of multiple motion tracking markers to a csv or other text file?

(I found this script but it seems to only work if the marker is set at frame 0, my markers are added at various frames)

Thanks

The script on this github page can export the data of each motion tracking marker.


Edit mode - Mirror on every axis I am currently trying to model a Companion Cube from Portal 2. I have started this by modelling the corner of the cube. Now I want to mirror it on every axis to get 8 of these, just like the original cube has them. How do I achieve this? I want the final model to be fully 3d-printable, with no intersecting edges or modifiers when I'm done.

You can use  the Mirror Modifier with an Empty.

Just align the Empty where you want to mirror your Object.
Example:

Add a the Mirror Modifier to your Cube and use the Empty as the Mirror Object:

Enable all Axis

Now your Object is mirrored in every Axis:


Can't render an inside-out cube? I have "double-sided" unchecked/disabled, but the backs of my faces still render anyway. I should be able to create a cube, flip normals, and render an inside out cube but it doesn't. How can I make it so faces do not show up in neither the viewport nor the render?

I've found that in 2.4 I could do this with an option called "No v.normal flip" which supposedly prevented the render from automatically flipping normals to face the camera. It would seem now blender still does that but there's nothing I can do about it.

How to make backfaces transparent

For the Viewport

Enable the "Backface Culling" option. This is found in the Properties Panel under Shading > Backface Culling. The backfaces will then show as transparent in the viewport.

For Cycles Materials

Connect the Geometry node's "Backfacing" output to the "Fac" input of a Mix Shader. Then plug a Transparency Shader to the bottom input of the Mix Shader and your visible shader(s) into the top one. In this way you can factor between your visible material and transparency, or any other type of material for that matter.


Big white circle for point light I am trying to add a point light inside a lamp. Here is a snap of my node editor (for the glass):

But everytime I put the point light inside of the glass material, a big white spot forms.

I tried removing the reflection node and the transparent node but the white circle still doesn't go away. When I try putting other lamps, like the sun or hemi, the white dot doesn't appear. I want to keep the point light though because it illuminates better.Please help!

The reason it's a big white dot is because the Point light size defaults to 10cm:

The only way to get "rid" of the dot is to make the point light smaller (which makes the dot smaller), but then you'll have to crank up the Strength to compensate.  If you crank it up too much you'll probably get a ton of fireflies.

The hard edges of the dot are because your glass has a roughness of 0.  If you set the roughness a little higher the edges of the dot will get softer.

What I would actually recommend is to model a light bulb (or candle flame) for your lamp, and set it to have an Emission texture.  I think that'll give you the best results in the end.


Motion Capture T-pose Bent At Hips As part of a larger project, I created a simple human mesh in MakeHuman, enabled MoCap with it in MakeHuman, and imported it inro blender as an FBX file.

When I 'Load and Retarget' the .bvh file I want to use, the model/rig dosn't go into a t-pose as it's supposed to, it is bent at the hips. This totally screws up the animation, as it looks like the figure is always leaning over. This happens with all the MoCap files I try.

I tried going into pose mode and bending the hips back into a normal position, but because the hips are constrained, I can't find a way to do that. I've re-made and exported the .fbx file, and re-downloaded the MoCap files with the assumption that it was just the files that were corrupted, but the problem persists.

Here's a screenshot:

The guide I've been using to do all this is this video by Remmington Graphics.

The MoCap files I'm using come from this site.

What is causing this issue and what can I do to fix it?

Thanks in advance!

Here is the .blend with the extra files packed into it:

EDIT: Here is the MoCap file, a FBX file and a DAE file.

https://drive.google.com/file/d/12RfzXPWZ-7SgoaRTD9LNmtk_bEmFIk0q/view?usp=sharing

https://drive.google.com/file/d/1MD2nwFtcIBvpLKuFYxUMyYAmB6oMREla/view?usp=sharing

https://drive.google.com/file/d/1konpJ3EGeyZH47Zf7OtbTI41O_fSxfqP/view?usp=sharing

The video author is using Blender 2.77a, you are using 2.79. This is important since Blender got a few tweaks on importing Collada files.

I am using 2.79b and tried to replicate your problem. I don't get the same problem but I do get issues when importing Collada if I do it the way its done in the video. I was able to solve it with this setting:

This fixed my issues, I hope it fixes yours.

Steps taken:

Exported character from MakeHuman as Collada file with Mocap skeleton
Imported Collada file in Blender with the "Auto Connect" setting
Selected the skeleton. Made sure its in Object Mode
In the MakeWalk v1.1.0 panel, pressed Load and Retarget and selected the Mocap file
Played the animation

It is also worth noting that I downloaded the "Daz friendly" version of the Mocap Files.


Lego Water with Dupliverts doesn't work! I made a fluid object, I made a brick object.  I set the fluid object to dupliverts in the object panel and added a remesh modifier set to blocks.  I selected the brick, held shift and selected the fluid object   and...   the bricks are placed incorrectly and there is a mass of oddly shaped doubles! How do I fix it?

It looks like the remesh modifier is generating the block grid based on the bounding box of your fluid simulation mesh. Since the shape of the fluid mesh is spreading out over time, the bounds of your mesh changes which generates an inconsistent grid over the animation.

A workaround for this problem can be to set up the fluid mesh so that it has a constant bounding box size. One way to do this is to add two thin cubes to the sides of your fluid and use a boolean modifier to union them to the fluid mesh:

Make sure the cubes are large enough to enclose the volume of your fluid and also thin enough so that they are not remeshed by the remesh modifier.

Now you can set up the remesh modifier next in the stack. Since the bounds of the mesh is now constant, the generated grid is a consistent size over the entire animation:

I have attached an example .blend file (Blender 2.80) with this setup:


Edges connected in strange way? I'm trying to edit my model but I found that when rotate any edge or move vertex from left/right side, the other side is moving too ? Like there is a mirror but there is not !! I think something is connected between those vertexs but I don't know what is that thing !!

You must disable X Mirror and Topology mirror in the
Mesh Options panel.

See the image below.


Particles with motion trails I am trying to recreate the following kind of static picture (particles positioned in a circle, with some kind of "motion trail" behind them to indicate a velocity) using Blender v2.79 and the Cycles render engine :

The easy part for me was to model the water molecule. To randomly position them, I created a circle and used the Particle System modifier. This is what i got so far:

The circle border is missing, but this is no problem, since I know how to add it.

Two questions remain:

1) How can I make the positions of the molecules more uniform, but still unordered (not regularily ordered at least)? E.g. I don't like that some molecules overlap.

2) How can I add the motion blur trail to the molecules? I've never done something like this, and "regular" motion blur, e.g. by decreasing the shutter speed, would also blur the particles themselves, which I want to avoid.

I took a look at the given answers, and here want to show you how I solved this question in the end.

@risingfall 's answer worked but has the downside that the trail only extent in certain directions relative to the particle object. Also, if I would like to change the molecule to another one later on, I would have to remodel the whole thing (yes, not too much work in this case, but nevertheless).
I tried to work with @Duarte Farrajota Ramos suggestion, but since my blender experience is not great I did not understand how to use the Btrace addon in my case. Anyways, the suggestion taught me that I can use an animated scene even if the desired result is static.

Here, I want to quickly show you how I ended up doing the scene so that it might help somebody else out:

I created a particle system on a circle object as above.
I chose "Grid" as the particle distribution method. With the according "random" slider you can add a random offset to the regular grid locations.
Under the velocity dropdown, I set the Random-Value to 1. This gave the particles a random velocity (random in direction and absolute). To prevent some particles being larger than others because they moved towards the camera, I set my camera to orthographic, so that all position deviations in the direction of the camera got projected into a plane.
I rendered the scene with a very slow shutter speed and a very awkward shutter curve (see image below), to get the desired effect of a motion trail fading out the further away from the molecule it gets.

To obtain the look of an unblurred particle with a blurred trail behind it, I re-rendered the last frame used in the motion blur, to get an unblurred version of the molecules "last" position, and overlayed them later in an image processing software.

The final result looks like this:

What I like about this solution is that the trails have the same color as the objects and have different lengths depending on the component of the random velocity in the direction of the camera. I could also remodel the molecule and would not need to do anything else than rendering again. Furthermore, the particle positions are not too random. :)
What I dislike is that one can clearly see that the blurred and sharp version of the image are overlayed in post (the trail loses the impression that it originates from a 3D-Object), but I have not implemented a solution for this yet. One option would be to duplicate the objects at the last frame and setting the duplicates velocity to zero. This way, the particles that create the trail would generate the impression that the trails comes "out of the particles" and does not lay behind them. I don't know how I would do this though.


Clothing modifier is pulling clothing up instead of down I have a character I am trying to clothe and I've done it by duplicating part of the character and modeling it after that, and by cloth sewing and with both I get the cloth sucking into the mesh or pulling itself upwards so far it doesn't cover the body anymore. The clothing mesh isn't parented to any rig or other mesh that I can think of.

here are the pictures of it in order from when it starts.

and the cloth never comes back down it just floats in air.
Any ideas?

There are two things that might be going on.  One is the collision size of the mesh collider:

Here my mesh collider's "outer" setting is so high that my cloth floats above it.  If that's too high, your cloth won't ever cling to your body.

The other thing is that your dress is too small.  It's about as wide as the cross section of the model, but just like a circle has to be pi times bigger than its diameter to wrap around, so does your cloth have to be about pi times bigger than your body to wrap around.  Your dress tries to minimize the size of the sewing lines, and to do that, it scrunches up at the waist, pulling the rest of the dress with it.