text:
Is it possible to update image texture by using image buffer pointer?
I want to know if it is possible to pass bpy.data.images["image"].as_pointer() to a C function to update image pixels directly, instead of using pixels.foreach_set() and pixels.foreach_get()
Edit:
I tried the following to change the float_buffer,but this did not work, the image stays the same. I have tried updating the image by setting the dirty flag, but this results in illegal memory access crash. I also tried calling image.update() and image.pixels.update() on the Python side hoping for a miracle lol.
void EXPORT set_all_pixels_to_white(ImBuf *buf) {
    float *pixels = buf->float_buffer.data;
    int num_pixels = buf->x * buf->y * buf->channels;
    for (int i = 0; i < num_pixels; i += buf->channels) {
        pixels[i] = 1;
        pixels[i + 1] = 0;
        pixels[i + 2] = 0;
        pixels[i + 3] = 1;
    }
}

Python side:
scene.mydll.set_all_pixels_to_red.argtypes = [POINTER(c_uint8)]
scene.mydll.set_all_pixels_to_red(byref(ctypes.c_uint8(my_image.as_pointer())))

From the source code that Blender Python uses to set image pixels, we can learn a thing or two:

The pointer you are sending to the dll refers to an Image. That is a different type than ImBuf.
You can get the ImBuf using BKE_image_acquire_ibuf(), so you have to mimic that function somehow in your dll.
An ImBuf is not always using the float_buffer. When ibuf->float_buffer.data == nullptr, it means that the image data is in ibuf->byte_buffer.data.
It is not guaranteed that an image has 4 channels, that's only when the image has an alpha channel. So to be completely safe when writing the pixel data, you should do something like

if (buf->channels == 4) {
  pixels[i + 3] = 1;
}

Perhaps this gives you some directions to get your code working.

Thank you, exactly what I needed. I missed BKE_image_acquire_ibuf() during my search of Blender source code.


text:
Python: How to link custom node tree to object (like shader nodes)?
How to make the following custom node tree be linked to objects, similarly to the way shader nodes are?
Python code from the Blender Template:
import bpy
from bpy.types import NodeTree, Node, NodeSocket

# Implementation of custom nodes from Python

# Derived from the NodeTree base type, similar to Menu, Operator, Panel, etc.
class MyCustomTree(NodeTree):
    # Description string
    '''A custom node tree type that will show up in the editor type list'''
    # Optional identifier string. If not explicitly defined, the python class name is used.
    bl_idname = 'CustomTreeType'
    # Label for nice name display
    bl_label = "Custom Node Tree"
    # Icon identifier
    bl_icon = 'NODETREE'

# Custom socket type
class MyCustomSocket(NodeSocket):
    # Description string
    '''Custom node socket type'''
    # Optional identifier string. If not explicitly defined, the python class name is used.
    bl_idname = 'CustomSocketType'
    # Label for nice name display
    bl_label = "Custom Node Socket"

    # Enum items list
    my_items = (
        ('DOWN', "Down", "Where your feet are"),
        ('UP', "Up", "Where your head should be"),
        ('LEFT', "Left", "Not right"),
        ('RIGHT', "Right", "Not left"),
    )

    my_enum_prop: bpy.props.EnumProperty(
        name="Direction",
        description="Just an example",
        items=my_items,
        default='UP',
    )

    # Optional function for drawing the socket input value
    def draw(self, context, layout, node, text):
        if self.is_output or self.is_linked:
            layout.label(text=text)
        else:
            layout.prop(self, "my_enum_prop", text=text)

    # Socket color
    def draw_color(self, context, node):
        return (1.0, 0.4, 0.216, 0.5)

# Mix-in class for all custom nodes in this tree type.
# Defines a poll function to enable instantiation.
class MyCustomTreeNode:
    @classmethod
    def poll(cls, ntree):
        return ntree.bl_idname == 'CustomTreeType'

# Derived from the Node base type.
class MyCustomNode(Node, MyCustomTreeNode):
    # === Basics ===
    # Description string
    '''A custom node'''
    # Optional identifier string. If not explicitly defined, the python class name is used.
    bl_idname = 'CustomNodeType'
    # Label for nice name display
    bl_label = "Custom Node"
    # Icon identifier
    bl_icon = 'SOUND'

    # === Custom Properties ===
    # These work just like custom properties in ID data blocks
    # Extensive information can be found under
    # http://wiki.blender.org/index.php/Doc:2.6/Manual/Extensions/Python/Properties
    my_string_prop: bpy.props.StringProperty()
    my_float_prop: bpy.props.FloatProperty(default=3.1415926)

    # === Optional Functions ===
    # Initialization function, called when a new node is created.
    # This is the most common place to create the sockets for a node, as shown below.
    # NOTE: this is not the same as the standard __init__ function in Python, which is
    #       a purely internal Python method and unknown to the node system!
    def init(self, context):
        self.inputs.new('CustomSocketType', "Hello")
        self.inputs.new('NodeSocketFloat', "World")
        self.inputs.new('NodeSocketVector', "!")

        self.outputs.new('NodeSocketColor', "How")
        self.outputs.new('NodeSocketColor', "are")
        self.outputs.new('NodeSocketFloat', "you")

    # Copy function to initialize a copied node from an existing one.
    def copy(self, node):
        print("Copying from node ", node)

    # Free function to clean up on removal.
    def free(self):
        print("Removing node ", self, ", Goodbye!")

    # Additional buttons displayed on the node.
    def draw_buttons(self, context, layout):
        layout.label(text="Node settings")
        layout.prop(self, "my_float_prop")

    # Detail buttons in the sidebar.
    # If this function is not defined, the draw_buttons function is used instead
    def draw_buttons_ext(self, context, layout):
        layout.prop(self, "my_float_prop")
        # my_string_prop button will only be visible in the sidebar
        layout.prop(self, "my_string_prop")

    # Optional: custom label
    # Explicit user label overrides this, but here we can define a label dynamically
    def draw_label(self):
        return "I am a custom node"

### Node Categories ###
# Node categories are a python system for automatically
# extending the Add menu, toolbar panels and search operator.
# For more examples see release/scripts/startup/nodeitems_builtins.py

import nodeitems_utils
from nodeitems_utils import NodeCategory, NodeItem

# our own base class with an appropriate poll function,
# so the categories only show up in our own tree type

class MyNodeCategory(NodeCategory):
    @classmethod
    def poll(cls, context):
        return context.space_data.tree_type == 'CustomTreeType'

# all categories in a list
node_categories = [
    # identifier, label, items list
    MyNodeCategory('SOMENODES', "Some Nodes", items=[
        # our basic node
        NodeItem("CustomNodeType"),
    ]),
    MyNodeCategory('OTHERNODES', "Other Nodes", items=[
        # the node item can have additional settings,
        # which are applied to new nodes
        # NOTE: settings values are stored as string expressions,
        # for this reason they should be converted to strings using repr()
        NodeItem("CustomNodeType", label="Node A", settings={
            "my_string_prop": repr("Lorem ipsum dolor sit amet"),
            "my_float_prop": repr(1.0),
        }),
        NodeItem("CustomNodeType", label="Node B", settings={
            "my_string_prop": repr("consectetur adipisicing elit"),
            "my_float_prop": repr(2.0),
        }),
    ]),
]

classes = (
    MyCustomTree,
    MyCustomSocket,
    MyCustomNode,
)

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

    nodeitems_utils.register_node_categories('CUSTOM_NODES', node_categories)

def unregister():
    nodeitems_utils.unregister_node_categories('CUSTOM_NODES')

    from bpy.utils import unregister_class
    for cls in reversed(classes):
        unregister_class(cls)

if __name__ == "__main__":
    register()

geometry nodes, compositor nodes, shader nodes?  The answer is yes, but the method is fairly complex.  You need to decide what you mean by "select" especially how to deal with selecting more than one object and you need to figure out how to use depsgraphs to recognize when the selection changes.

@MartyFouts by select I mean just like shader nodes with a few differences. Only one custom node tree per object and each object has to have a unique node tree (so the object cannot be duplicated and the node tree shared between two objects).

You should just be able to link to bpy.types.Object instead of bpy.types.Scene in that case.  Have you tried that?  If so, what didn't work?

@MartyFouts I can only use those for custom data I think. Looking through the basic custom node tree example there doesn't appear to be an option to change context from scene to object..

Could you add some code to your question showing what works with scene?

@MartyFouts I added the sample template. This node tree is tied to the scene, but not to objects.

Let us continue this discussion in chat.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


text:
Color beveled nurbs path according to the x-y-direction in the final camera view
My question is very similar to this one, but the answers there don't capture the essence of the problem imo. Assume you have beveled paths in Blender, then every location on the path has a tangent vector that points in the direction of the path.
In the coordinate system of the camera, assuming the z-axis is our viewing direction, we are only interested in the x-y-portion of the tangential vectors. What you want to achieve is that path-parts that go into the same x-y-direction have the same coloring. This also means that a vector that points into the opposite direction another vector, will get the same color.
For people working with visualizations of vector fields, this is nothing new and besides coloring the magnitude of the vectors, one major application. A good test-case is a ring viewed from above because it contains all directions and one can easily check the correct coloring. I came up with the following solution in Blender 2.81

This is a simple nurbs-circle. I used the Geometry node to get the tangent vector and after converting the coordinate system, one can calculate the direction using trigonometry. I have 3 questions, but the first one is the major problem I'm trying to understand:

In the small rendered view, one sees that on the blue and red spots, it almost looks as if the coloring changes too fast. It doesn't look so severe in the preview but I have the feeling that the color between blue and red on the left side takes a too large portion. Did I do something wrong or is there a reason for that?
Is there a simpler node-structure that achieves the same?
Is it a bug that the "Hue Saturation Value" doesn't work if the second color doesn't have the saturation set to max?

Your additional question link is an Skype invitation, is that normal?

Good lord.. thanks for pointing this out. I fixed it.

HSV is non-linear, you're right. But another question: if you're only interested in 2 dimensions, why are you encoding in 3? Wouldn't RG do, without B?

There are many different ways to do this, but using the Hue value is often used in science. Here, I just wanted to see how to turn the tangent direction into color with Blender. To get beautiful color gradients out of this, one could take the tangent-direction t and use an appropriate parametric function {fx(t), fy(t), fz(t)} and use this as coordinates in XYZ-color-space. Then you can get whatever color gradient you want, and colors will have perceptually the same distance. I'll try this later.

That's a beautiful node setting. I will try to explain some problem first:

You shouldn't use emission shader for your output, if the output is Color and you want that color directly show on your screen, please directly connect the Color socket to Output Surface socket. This post elaborated more detail of color output setting
What you mean too fast? Human color perception is complicated, we try a lot, a lot of method to describe and organize color: sRGB, Adobe RGB, NTSC, CMYK or even Pantone®. Blender using sRGB as default output color and if my memory is correct, purple will be strongly receive for our eye in normal sRGB situation, Blender is using this solution as standard.

Back to your question:

Change the color management in properties panel, View Transform: Raw
Not sure, emission is useless in your situation, and the final subtract node can be done by changing the HSV node color
Directly connect the color to the output surface socket should fix the problem. Emission is not final color output for Cycle and EEVEE.

BTW the node itself is pretty simple in my opinion. All is math calculation, Computer should love these nodes.

Thank you for this answer. As a on-off user of Blender (just when I need something to render), I didn't know that I can go without a shader. Also, your colored ring looks exactly how I want it. Just compare how much larger the pure red transition is compared to mine. It was really hard to describe what I meant by "certain colors change too fast". Let me look carefully into the information you provided. Thanks again.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Any bubbles simulation + Eevee Tutorials?
I am actually trying to make steam from a hot drink cup. But in a cartoon style. This is the reason I am not using the Smoke simulator. So maybe the Particle System settings for soap bubbles would do, I would just replace the bubbles with my own meshes.
Needless to say I have searched and searched only to find old tutorials for Cycles and even Blender Internal.
Could anyone care to share a tutorial on making floating thingies (not necessarily bubbles)? I am only interested in the Particle System/Physics workflow and settings.
Thanks a bunch in advance guys :slight_smile:
Cheers!

Hi. Asking for tutorials is off-topic but you are welcome to ask the actual question here (although ideally you would show what you have tried and where specifically you are getting stuck, otherwise the answer itself would have to be tutorial sized). Thanks.

I was able to figure out the basics and take it from there… (hopefully it will help someone).
Basic Settings, as in Barebone settings
Requirements:
Domain - This is the container where the simulation will happen.
Use a cube, adapt it to the dimensions of the simulation. E.g. if it is for something that will float or elevate (like smoke) then a vertical rectangle would do.
While the cube is selected, go to the Physics Properties tab from the Properties right panel.
Enable Physics for: Fluid, type: Domain, Settings: Domain Type: Gas, everything else stays untouched for now.
Force Field - Inside the cube, at the bottom add a plane. While the cube is selected, go to the Physics Properties tab add a Force Field to it. Type: Wind, Settings: Shape: Plane, Strength: 0.700, Flow: 0.500, everything else stays untouched for now.
Particles Emitter - Inside the cube, above the Force Field plane, add a 2nd plane. While the cube is selected, go to the Physics Properties tab. Fluid, Type: Flow, Settings: Flow Type: Liquid, Flow Behavior: Geometry, everything else stays untouched for now.
Also add a Particle System to the same plane - From the tab above, the Particle Properties, click the “+” sign in the upper-right corner to add it. It will be called “ParticleSettings”. Keep it as an Emitter. Change the Number of particles to whatever suits your simulation. Emission/Number: Default is 1000. I had enough with 100. Check when you want them to end, default is at the frame 200. Check for how many frames they will live, default is: 50 frames. Cache (Optional, if your RAM can afford it): Cache Step: 6, this will smooth the simulation. Rotation (Optional): checked, Randomize: 0.5.
Physics: Newtonian, Mass: 0.5.
Multiply Mass with Size: checked.
Default shape of particles is Halo (little spheres). To change it to an object of your choice: Render section of the same tab, Render As: Object, Scale: 1.000, Object, Instance Object: “your obj here”.


text:
Need workflow to render color-corrected video
So I got the video file imported into Blender via the Node Editor. I already played with the nodes to my satisfaction. I need to rotated it still, as it was shot with a phone (vertical). After that I need to output it to a video file format, like MPEG.
Will I need to do it in 2 parts?: 1.Output it with the colors corrected, then 2. Rotate it?
Or can these 2 things be done before outputting?

related: http://blender.stackexchange.com/questions/45952/rotating-images/45953#45953

You can do it before outputting. Add a "Rotate" node (from "Distort -> Rotate") and change the degree by 90 degrees.

After that go to your render settings and swap the X and Y values.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
How can I make an addon that stores arbitrary data with a .blend file?
What I'm trying to do
I'm trying to make an addon that can import Minecraft model files. Unlike many 3D files, Minecraft files use a hereditary system where each model file can have a parent file which it inherits elements from. As such, I need a way of locating the parent file referenced in the model, which is represented as it's path relative to a "resource pack root directory"
How I'm going to do it
For each blend file, I'll have the user specify the resource pack root directory somewhere in the properties panel. The problem is that I don't know how to actually store this value once it's set. So how do I store it?

You can set this data inside custom properties: https://docs.blender.org/manual/en/2.79/data_system/custom_properties.html If you do it the python way as described below, it's just adding some property to the object. If it's something blender is not familiar with, the Ui will display it a custom property to you.


text:
Bge action editor fade out
I'm making a fighting game in the game engine, and I have 2 action actuators. One is always playing an idle animation on layer 1, and the other plays the attack animation when I press w on layer 0. As I can't always be sure the idle animation will be on frame 1 when the attack starts, I have it blend in to the attack animation, and it looks fine.  However, when the attack ends, it snaps back to whatever frame the idle animation was on. Is there a way to blend back to the idle animation or assure it will be on frame 1 when the animation ends? Thanks.

Add a Boolean property to it to keep track if it's active.
A Boolean is a simple True / False variable.
Have the idle animation loop while True,
then reset to the first frame when False.
Use a Property Sensor to check it's value.
https://docs.blender.org/manual/en/dev/game_engine/logic/properties.html

And I assume on the actuator which resets it to frame 1, you have that fade in as well?

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
How should I create a realistic landscape based on a real place?
I'm making a short film about a flying carpet, and the background plate for the green screen needs to be CG.
I have this model based off terrain data of the actual location taken from Open Street Map:
And I need to make it look kind of like this, except photorealistic:

What's the best way to do this? I'm using Cycles by the way. Any help would be appreciated.

This is a quite long task to do.
First you'll also need some texturing for the ground.
Then you'll need to have the models of all the building, then texture every one of them. Then the same thing for the roads and so on...
Their is an addon call blenderGiS (https://github.com/domlysz/BlenderGIS) which can take care of importing google data, i.e. building (the one google knows the shape) and road (it import the road a curves i believe).
This solve partially the problem of how to get all the 3D model in blender. However, you'll have to do some modelling for the road or if you want very realistic building model since google has only the very low poly models of building.
Then you need to texture everything.... So good luck !

I'm thinking of using a particle system for the buildings, and open street map has road textures. How would you recommend texturing the mountain?

One thing you can do is use the satelite image from google earth as a texture for your ground. I did that for texturing a city, it works quite well. You just need to align the texture with your ground)


text:
Blender knife tool options
So I'm 3d modeling a logo and there's one oddly shaped part that needs to be extruded. I am trying to use the knife tool to cut it out, but every time I finish it deletes the face. In the operator I can see the option that I obviously need to change, but it's grayed out saying redo unsupported. What do I do?

Knife tool is interactive one so you change its options while it's activated (i.e. before confirm). Still I'm not sure why it deletes the face once cut is finished. Could you add example screenshot ?

N-gons with a hole
Currently holed-ngons (e.g. a doughnut section) are not supported. If in the cutting process you are creating one of those, the software will try its best in finding a way to continue anyway (in this case by splitting the ngon in two and as a side effect deleting th inner face).
In the picture below you can see the difference of behaviour of the command upon the same mesh but with different topology:

I suggest to continue knife projecting the shape as you were doing and then simply re-fill the boundary with a new face. Just select the hole boundary and press F or with another method (e.g. fill holes operator).

Here's an old forum post about the topic: https://blenderartists.org/forum/archive/index.php/t-328732.html


text:
How do I make a delay between when a sensor is activated and when the controller activates?
So I've been working on this car game and want the level to restart when you hit the ground outside the track.
I have a collision sensor on the car looking for colliding with an object with the property "Ground" Next, I have that running through an and controller into a scene actuator that restarts the level.
The problem is that the level restarts as soon as you hit the ground outside the track. How do i add a delay between the collision sensor and the scene actuator?

This is not possible. An event already happened. What you do is to describe the operations on the event.
But you can lift it to an higher abstraction level. Split the logic into two parts:

on collision start a timer
on timeout switch the scene

Reference:

How do you add a cool down timer?


text:
Deleting the insides of model/ hollowing it
Hi i'd like to ask if i can delete all the faces and vertices from in side my model,
Here's my model, it looks fine, but there's problems, like some parts of it have two faces so it sort of glitches. (near the back of the foot)

And also, i used ALT + E to extrude individual faces, that made all of inside of it just horrible, and i want that the whole model to be hollow in the inside, like so
This is a cube

And this, is inside of my model,

So, my question is, can i delete all this messy blocks inside of it without any noticeable changes on the outside?
Also, i'm sort of new to blender so please tell me what you mean and how i would do it. Thank you.

Did you try Remove Doubles?

Don't know how to do that. Sorry, i am new to blender. I'll edit it saying i'm new because don't want this to happen big time again.

Select all vertices in Edit mode (press A to do that) and then press W > Remove Doubles

Didn't work. just deleted random bits on the side of the model.

Just noticed, you have your Normals all calculated wrong. Select all vertices and press Ctrl+N.

Oh, i see, sorry for the duplicated post, i searched for 1 and a half days for a answer on the internet, damn. I'll try what they have there, also, what do you mean my normals? Sorry for not knowing what normals are but i don't EDIT: I tried what they said, didn't work for me.

Normals basically tell which direction a face is pointing, right now they are all pointing inwards. Selecting all vertices in edit mode and pressing Ctrl+N will fix that

Let us continue this discussion in chat.

@NoviceInDisguise With all the wacked-up, non-manifold geometry in the model, recalculating normals won't do much of anything useful.

How do you determine if a face is interior or not though? By normals?

You can use the Select Inner Faces operator,  and then delete then. To do this, in 3D view space, go to the header, then Select, then Interior Faces. Then you can press X > Vertices.

That doesn't work for this sort of model. I am giving up on this model now after a long chat with someone, but i'll keep this place up for anyone who might have the same problem as me.


text:
Easy way to snap then merge a piece at the end of an array
I'm fairly new to Blender and I'm trying to make a railing on a roof top.
I made the base shape, added array modifier then applied it.
My problem arose appeared when I had to make the ending of the railing. I copied one of the tall supports and moved it to the end.
I don't know how to make it snap to the bigger shape and then merge the edges so it's one seamless shape. I tried turning on snapping during transform and selected edges, faces and vertices but that didn't help, it didn't snap to the correct place.
Another thing I'm wondering is if the method I used to create the thinner bars is correct. I subdivided the top bar in sections, insert and extruded the bars but I didn't merge/fuse at the bottom, is that OK?

Thank you, that did it. I hadn't had noticed it until now.


text:
Aligning empty object with Bezier curve point using Python
I'm using a Bezier curve to generate a shape. Once I'm happy with the shape I process it with a script I wrote. Among other things it adds 2 empty objects: one at the start of the curve, one at the end of the curve.
I can't figure out how to rotate the empty objects so that they point in the same way the curve is pointing. Or how to align the empty's Y axis to the end point normal?
I access the end point data via curve.data.splines.active.bezier_points[pointId] but I couldn't find a way to get rotation or normal information.
Orientation that I'm trying to copy from curve end point to empty axis orientation.

End result I'm trying to achieve: the empty's Y axis is aligned with the direction of the last curve point.

Use the follow path constraint
When it comes to putting an object at either end of a curve, the follow path constraint, with fixed location, follow curve. An offset factor of 0 is one end, 1 the other.

import bpy

context = bpy.context
bez = context.object

bpy.ops.object.empty_add(location=(0, 0, 0))
mt1 = context.object
fpc = mt1.constraints.new(type='FOLLOW_PATH')
fpc.target = bez
fpc.use_curve_follow = True
fpc.use_fixed_location = True
# dupe it
bpy.ops.object.duplicate()
mt2 = context.object
mt2.constraints[0].offset_factor = 1

Wow, that was much simpler than expected. Thank you very much!


text:
Rig moving after clearing all frames
I've been trying to create some new moves for my creature and I created a new action for it. After clearing all the frames, some of the frames are still yellow (left-down corner frame numbers) and the foot is moving in an odd way.
Can' t understand what is this..

Here' s the .blend file: http://www.pasteall.org/blend/37660

Also, could you answer to this one: Why can' t I move the spine or torso of this creature? Is it just bad rig or I've missed something important?


text:
Creating an eye/eyelid rig for dragon without shape keys
I've been creating a dragon lately and now trying to create a rig for my dragon. I've managed to create a basic rig for other body parts of my dragon, but I' m really stuck at creating eye and eyelid rigs as I can't find tutorials of creating them for dragon.
This is how my eye looks like. I've created it by using lattice to stretch it (so it would look like a real dragon eye). The eyelids are separated from the eye itself.
Dragon eye with lattice and eyelids as seperate objects

When I move the eyelid in front view using 3D cursor as pivot point, it moves nicely around the eye, but I can' t understand how to make this work with bones.
Eyelid open

Eyelid closed

The second problem - I can' t make a basic eyerig for this kind of eye, because it is not round and stretched by lattice. Whenever I try to move the eye somewhere using the eyebone in pose mode, it'll look like this. How could I overcome this problem?

Concerning the eye movement, you can use a UVWarp modifier to your eye.

The principle is to set two objects (empties) to shift the position of the UV map of the eye.
Moving (or inserting key frames) one empty will shift the UV map to obtain the result.
Here is a closer view of the modifier :

Edit :
Concerning the eyelid animation, if you set the bone origine at the same position your 3D cursor is (as you said you can rotate it manually), that may work.

Another edit : a rigged version of the eye animation.
The principle is simply to add a "Bone" and define a group named "Bone" for the Iris circle. That allow to play on the position and X-scale of the iris.

The Bone group is the iris / center UVs in the image below :

Oh. That's a cool solution. I will truly try this out, but what I actually prefer is mesh. I think it would be easier to animate it later on when I need the dragon to look at certain places.

I managed to create some kind of eyerig for my character, which partly solves the problem, but now there' s a problem with the Limit Rotation constraint. It's moving so weird.
When I look the bone rotation it's all zeros. When I try to use zero degrees as min value, my eye pupil will move to somewhere else.
https://gyazo.com/20346fae0cf07d28d6a0ac564497790d

edited for a rigged version of the iris movement.

authors: Аркадий Шевцов


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How to take an object with textures applied in nodes and put it into unity
So I used the sapling add-on to create a well detailed tree. Under the curves tab I check the Use UV for mapping box and the went into cycles render mode. I then opened up the node editor and applied the textures to the tree with nodes. When I went into render view all of the textures were in place and correct. But when I finally saved the blender file and the put it into unity it didn't process the textures. Do I need to uvmap the tree instead of applying the textures through node editor, for it to show up in unity. I would very much appreciate if someone could clear this up for me.
Thanks, Nova

The various exporters cannot handle Cycles materials so Blender Internal should be used for now when setting up textures that will be exported.  http://blender.stackexchange.com/questions/19299/exporting-cycles-rendered-models-to-be-used-in-opengl/19326#19326

Also, you may need to bake some of the textures.  http://blender.stackexchange.com/questions/24048/create-a-low-poly-mesh-with-high-detailed-textures/24127#24127
http://blender.stackexchange.com/questions/24111/making-texture-atlas-for-only-some-part-of-objects/24112#24112


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Applied Subdivision Surface Modifier To a Mirror Modified Model The Model Enveloped in on Itself
So I was doing a fairly simple model of a Glock hand gun. I had already applied a mirror modifier to the model, that I had so far (which was the grip). Then I applied the subdivision surface modifier. At the point where the mirrored part of the model and the "real" part of the model met it collapsed inside of itself. Bellow will be a picture of the model. I would really appreciate it if someone could tell me how to fix this so I can get back to working on my model. Also the picture is the bottom part of the grip, it may looks like two smaller grips, they are supposed to form one. But like I said it collapsed in on itself.
Thanks, Nova

Your model seems to have faces at the border between the two halves, so to Blender it looks like they are separate.

Remove these faces
make sure that the mirror modifier is above the subsurf modifier
make sure that Merge is enabled for the Mirror modifier


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.blend files not importing into unity
So I for the past week or so I have been having extreme difficulty trying to import .blend file that I made into unity. When I either drag or import the .blend file into unity I automatically get a message saying "Blender has stopped working", as if the blender was even running to begin with,which it was not. Also in unity in the error bar on the bottom of the window I get the message blender could not convert the .blend file to FBX file. The only way I found to work around this,that only partially works, is to export the .blend as a .obj, but this will not work if your .blend file has multiple objects. I'm posting this to both the unity stack exchange and the blender stack exchange as either program could be at fault. I would appreciate any help I get get immensely, as this problem has been one of the most frustrating problems to date.
Thanks, Nova

Possible duplicate of Is there a way to export an object to Unity 3D while keeping any applied textures?

Can you upload your model? Does happen with all models? If so try reinstalling blender, and make sure no third party addons are breaking this.

No It's nothing to do with textures, I used to be able to just drop .blend files into unity just fine, but I got a  new computer installed blender and unity and this is happening

Thanks for the suggestion it worked, I'm surprised that not many other people have reported this problem.


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Is it possible to simultaneously adjust the cache settings for multiple objects?
For example, changing the start and end of a simulation for multiple objects with soft-body physics applied.
Changing this:

Would change the cache settings for SoftBody.1, SoftBody.2, SoftBody.3 (which could all have different soft-body settings).

can you show me where this board is open

I've come up with two solutions.
(1) If the physics settings are the same for all objects:
Change the cache settings for one object, then link the modifier to all other objects using Make Links > Modifiers (Hotkey CTRL + L)
(2) If the physics settings are different:
Use Python (Blender 2.8):
import bpy

# get objects in selection
for obj in bpy.context.collection.all_objects:
    if obj.modifiers:
        for modifier in obj.modifiers:
            if modifier.type == "SOFT_BODY":
                # adjust range here
                modifier.point_cache.frame_start = 1
                modifier.point_cache.frame_end = 3000


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Export Problems!
I'm trying to export a file from Blender to OBJ and when I click export, and then click obj, the whole file menu disappears.I then have to close blender and restart.
Please Help!!

authors: अक्षय परूळेकर


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BVHTree.FromPolygons not accepting vertex list
I'm having an issue using BVHTree.FromPolygons. It doesn't appear to be accepting my vertex list.
Documentation of the function: BVHTree.FromPolygons
Example:
import bpy
from mathutils import *
from mathutils.bvhtree import BVHTree

# This one doesn't work
verts = [Vector((0,0,0)), Vector((0,0,1)), Vector((0,1,1)), Vector((0,1,0))]

# Neither does this one
verts2 = [(0,0,0), (0,0,1), (0,1,1), (0,1,0)]

# Gives "TypeError: BVHTree.FromPolygons"
print (BVHTree.FromPolygons(verts, [0,1,2,3]))

It gives this very vague error message in the console:
Traceback (most recent call last):
  File "C:\planefromnormal.blend\Text.001", line 9, in <module>
TypeError: BVHTree.FromPolygons
Error: Python script fail, look in the console for now...

Anybody know what I'm doing wrong?

The second argument is a sequence of polygons, try BVHTree.FromPolygons( verts2, [ (0,1,2,3) ] )

Well now I look stupid haha, yep that did the trick. Thanks!

Oops, it wasn't the verts that was the problem. It was the polygons sequence. It requires a sequence of sequences:
BVHTree.FromPolygons( verts2, [ (0,1,2,3) ] )

Thanks lemon for the answer!


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Walk animation missing
I've been trying to create some animations for a creature. I've created a walk animation for a creature already and right after I created an attack animation. However, the walk animation is gone somehow. I can't even find it when I search for it in action browser.
Could you please tell me where it might have gone?

Here' s the .blend file: http://www.pasteall.org/blend/37646
Don' t mind the weird animation. I have no idea how did that happen.
The smoke domain box ruined it..

If this has not changed in the latest versions an action will be deleted when it is not used (referenced) in the NLA-editor. You can keep currently unused action by adding a fake user (reference) with the 'F' button.

Oh. Thanks. Fortunately I saved the animations in different .blend files. Is it possible to import the walk cycle animation from one .blend file to other .blend file?

@TheLast_BlenderBender In the menu pick File/Append select the .blend and navigate to Action . Related: http://blender.stackexchange.com/questions/81/how-can-i-reuse-existing-materials-objects-etc-from-an-existing-blend/83#83


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Strange black artifacts in ambient occlusion map
I've been trying to create an AO map for my dragon model. However, I've been struggling with this one quite long time already as the baking process takes quite much time aswell. I searched a solution for my problem in the Internet, but it seems I can' t find solution for my problem.
That's why I'm here to ask your help. Maybe you could tell me what I'm doing wrong. The model part I'm trying to bake AO map from is here and the AO map with artifacts is also provided below.
I also don' t know whether I should bake my AO map with cycles render engine or Blender render engine. What is the difference?
THE OBJECT I'M BAKING AO MAP FROM

THE AO MAP

THE AO BAKING OPTIONS OF MY CYCLES RENDER

Try to increase Margin and check for double vertices / faces in model. It seems that something is overlapping. Keep in mind that amount of render samples will also affect on AO map quality (hence the more or less visible noise of AO).

The margin seems not to be the problem at the moment as the purpose of margin is to cover the islands of the UV map properly so the edges of the UV islands wouldn' t be unbaked. When I increase the margin, I'm afraid some islands will apparently collide... Hmm.. I didn' t understand the "check for double vertices/faces in model" part. I have placed my UV islands so they wouldn' t overlap, but I don' t know, they might somehow overlap..

By double faces in model I meant possible overlapping geometry in mesh, not in UV map. Try maybe baking into completely new image (not rewriting), this is very unlikely to help but recently I did have a problem with that. And for baking AO Lightmap Pack is also rather useful option instead of unwrap with seams.

Did you set a material on it ? It may come from it.

I had the default grey material for my mesh. About the suggestsions, Mr Zak, I will try your suggestions. Although.... I spent soo much time creating nice UV map (placing the UV islands on my own)...

I support @MrZak answer. I am shure you have two overlapping meshes in the scene. Be shure the hidden mesh will not be rendered, too. Disable the render option for the hidden object in the outliner.


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Mirror selection not working properly
I've created a dragon model and now I'm trying to unwrap my model so I could later on texture it. I've wanted to simplify the process of creating seams by mirroring selection. For example, I have teeth and I don' t want to create seams for each tooth separately.
So here's my question to you:
Why does Mirror Selection fail all the time I try to mirror the selected vertices on my dragon model? I know that Mirror Selection works only in Vertex Mode.
I think the problem is somehow associated with the matter that I haven' t applied the rotation or scale of my model (even though I did lately) or with the fact my model wasn't originally on x-axis as I started creating this model really long time ago and I know I could have done many things differently.
Here's an image to describe my problem:

If your model is symetrical, why dont you cut it in half, add a mirror modifier and mark your seams ?

what kind of rotation does the mesh object have? Quaternian? XYZ euler?
Are the local axes aligned with the global axes? Is it symmetrical along the global x axis with the line of symmetry intersecting Y=0?

As I mentioned earlier I've done few things wrong, which I could have done differently. The thing is that I've already created animations for my model and when I cut my model in half and use the mirror modifier it would make my model have every move mirrored based on the left side of the dragon's body...

The object has XYZ Euler rotation and so does the parent of my model (which is armature of the model). And... your next question helped me alot... The origin of my model wasn' t in the middle of my model (I guess when I rotated my model to x-axis I forgot to set the origin back to the geometry)

Try those two things:

Check if your pivot point is set properly. It has to be in the middle of your x-achis. To set your pivot hit SHIFT+CTRL+ALT+C (or hit SPACE and type "set origin"). Then choose "Origin to Geometry" or "Origin to Center of Mass".

Now your mirror selection should work correctly. If not, also do point 2:

Delete one half of your mesh. add a mirror modifier. mark your seems. Apply your mirror.

Thanks for the solution. That' s exactly what I forgot to do (the first thing you mentioned) :)


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Strange anomalies with weight painting
I've been trying to create a rig for my dragon character and I'm doing weight painting right now. However, some strange anomalies keep getting on my way.
Picture of the anomaly is too big and so I've added it as a link instead
When I select the vertex group of the bone, it can be seen that there are no other vertices selected on the other leg, which makes it really hard to understand.

Here's the same picture in weight paint mode and none vertices of the other leg are affected by the paint..

Problably a rotation problem. Blender knows how to mirror on X for the armature. Face your model and armature to -Y in object mode. Then apply rotation on both (ctrl+A and rotation).

The problem is that I am not trying to mirror weight paint. It's moving the vertices itself. ...Or I am misunderstanding you..
There' s a topology mirror to solve that problem anyways?

Looking at the gif, at least two other bones are moving when you move that shin bone. The most likely explanation for your issue is that you have parts of the other leg weighted to one of these bones.
Edit:
Another thing you could try is to set the armature modifier to deform the edit mode mesh, pose it so you get the deformed mesh and enter edit mode.
From there, select one or the deformed verts and open the right hand panel in the 3d view ('N' panel). One of the sections there lists all the vertex groups and their weights that apply to that vertex. This should help you track down where the problematic weighting is coming from.

It's weird...
I checked every bone manually - looked whether there' s weight paint on the other leg and also looked for the vertex groups. There were no other vertices in the vertex groups.
I also tried to use the "Clean" weight tool for some bones. It didn' t solve the problem...

@TheLast_BlenderBender updated my answer with a way to help track down errant weights. Try that and see what you find.

Thanks for the tip. The problem seemed to be in the "X mirror -> Topology Mirror" option. I don' t know... I had it on earlier, but it didn' t affect my mesh earlier.. I think my model truly is facing the wrong axis to make Topology Mirror option work, just as "Lemon" said in the comments. Anyways big thanks for this.. Your tip made me discover the problem :)


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Creating UV maps for my dragon
I've been creating UV maps for my recently modelled dragon creature. I've got plenty of questions associated with creating UV maps for my model.
How large should my UV maps be? I want to export my model into UE4 game engine. I also want to add that my model is separated into three objects - head parts (eyelids, eyeball, pupil, headbones), the body and the wings.
Should I add all the parts of my model to same UV map?
Here are the pictures of my model and then the UV map of the part of my model.
HERE'S THE OVERALL MODEL

THE BODY

THE WINGS

THE HEAD PARTS

An UV map does not set the size of the textures you will use in your game engine. Try to use a 1024x1024 texture then change it to a 2048 (or any size) : you'll see the UV map will be adapted to the size.
What matters is the number of textures you will use (generally one per UV map), the size of them and the way you use these textures in "an optimal way" (so that the less part of them is useless).
Have you tried the "smart uv project" option when uv unwrapping ? If you do (make a copy before trying that), you'll see that the uv map is cut into plenty of small parts. The aim of that is to optimize the useful space of the textures while keeping the relative surfaces of the faces.
So for instance, if you look at your wings UV map, you can see that there is plenty of space in the texture that is not useful. So for a same texture size, the actual resolution for the wings will be lower with your UV map than it can be with the "smart uv project" option.
The counterpart of that is you cannot (or hardly) paint directly on such a texture. But you can do both : keep your UV map, use it in Blender with a big texture size, then bake on another "smart UV project" uv map with a lower texture size.
To summarize : all in red here is lost surface

For the textures, you can use a mipmap technics : the idea is to define several textures for the same UV map. The first texture is the full resolution (let say 1024, for instance) and is applied when the camera is very close to the model, the second texture is half resolution (ie. 512) and is shown when the cam is at some distance, the next texture is smaller again (ie. 256) and is used when the model is very far. Probably UE has built in functions to do that automatically.
Also the polycount of your mesh is important if you want to use it in a game. I cant be sure of a number for that (as computers are faster and faster) but for a main character around 20k tris is more or less a limit, generally. But there is no rules as all depends of what you want to do in your project.
Another point : sometimes symetrical parts of the mesh can share the same uv map and so share the same texture (when nothing needs to be different for each side). In consequence a same texture size will give a higher resolution in the game.
A last remark : imagine that in your game in UE, you want the colors of the eyes change (let's say depending on the dragon's mood), probably you'll need to set the eyes on a separate texture to do that as if not you'll need to change also the texture for all the head.

Thhanks for this really nice detailed post. When you mentioned mipmap techniques, you meant LOD (Level of Details) for example in UE4, so you would have different texture maps for different levels of distance?
"Symmetrical parts should share the same uv map" - you meant I should place symmetrical uv islands in the same place so I could place the texture on them and have more detail?
About the polycount, I was planning to use decimate on my model and apply the high-to-low poly baked normal map on it

@TheLast_BlenderBender, yes LOD (for mipmap). For symetrical (to be done mirrored preferabally), yes : imagine for instance left ear uv map at the exact same position as right ear's one. For decimate, I am not very experienced of it, but have a try...

Hey. I've heard that there' s a technology called UDIM. Could this be used to solve my multi UV map problem?

UDIM is an easy way to handle many textures/uv maps as if it is one big textures grid. This is mainly a facility. But... Blender does not have this built-in function (but you can find addons for that but they are more or less simple to use... so up to you). Using UDIMs change nothing about texture space optimization principles

Your question can not be answered that easily.
You have to know what amount of quality you want to achieve. For example the dragons from Game of Thrones are using 120 Udims (UV Maps). But for an game engine 1-3 Maps are enough.
The easiest way is by only using 1 UV map. This way you make sure that everything is scaled the same way. Because you dont want that some parts of the texture look more squishy than others.
If you want to use more than one, i would say you take one for the body and one for the wings with the head parts. but be aware that you have to arrange the wings manually in the uv editor, because blenders auto pack does not handle them very well. you want as less empty space as possible on your uv map!
As a resolution i think 2k or 4k will be enough. even for a single uv layout. also more than 4k does not run very smoothly in game engines.

Oh. Thanks for your comment. I was thinking that 4096 will not run smoothly anymore. But yep... after all it depends on the things that are used in the game :P

authors: Андрій Левченко


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Particle system domain box deforms the character (smoke effect)
I've been trying to create an animation for a creature where he slams the ground and there' s shockwave effect right after the animation.
However, I moved the domain box, where the smoke effect takes place right under the creature that slams the ground and it suddenly deformed the creature (so the creature fitted right in the domain box somehow).
The domain box seems to have animations saved somehow. Maybe this might cause the problem.
I am not sure what causes it.

I will include the .blend file soon. Blend exchange is bugging for some odd reasons for me. Can' t upload the file..

What's wrong with Blend Exchange. Can' t upload anything there.

Ahh.. here' s the .blend file: http://www.pasteall.org/blend/37646

I heard that Blend-Exchange is giving trouble! Any details?

Not sure. It just didn' t upload  the file.. So I used pastall instead..
I tried to upload the file for half an hour, it still didn' t do anything. It seems strange though..

Did you enter the url of the question?

Also can you check in the javascript console for any errors?

I did enter the url of the question. However, I don't use firefox myself to have firebug and check for javascript errors.. Don't know...

Let us continue this discussion in chat.

Your rig object has a non-uniform scale, giving the character a squished appearance.
To fix this, clear the keyframes on the scale (as the scale doesn't actually change, this won't affect the appearance of the animation), then copy the X or Y value to the Z value:

This shouldn't have been caused or otherwise had anything to do with the smoke simulation. Perhaps you may have accidentally changed the scale while Auto keyframe was enabled (as it is in your screenshot)?

If you use the particle system yourself, has Blender crashed?
I can' t understand whether it's my computer or some bugs in the particle systems that cause crash when I try to do something with it.

@TheLast_BlenderBender It's working fine for me.. Is it possible you are running out of memory?

Yep. Might be. Need to get something better for doing stuff like this :)


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Can Blender take two video files and morph one into the other?
Is it possible to do something like this:
https://www.youtube.com/watch?v=t0lcSHYiOJg
with two video sequences in the video editor or elsewhere in Blender?

In short: you could do it manually by morphing tesselated plane with video in texture from one shape key to another. If sequences have no highly significant difference then it would look more or less acceptable.
This tutorial will help you:
http://www.blendernation.com/2014/01/06/morphing-photographs-with-blender/

Yes, you can but it's awkward if you want a high-quality morph. For each frame, you need to create a plane with a material that blends from one frame image to the other. Mark distinguishing features with vertices for the first image, then save as shape key. Move vertices to mark same features in second image, save as second shape key. UV unwrap each shape key and map to each image in the material. Blend equally between shape keys and textures progressively through the videos.

When you use the word "morph" it implies some processing that is not a feature of blender.
The closest thing blender can do is that you can animate the transparency of one video strip so that the video strips beneath it are revealed.  This is done with title cards pretty often (although title cards are usually static, they are still strips in the VSE).


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Adding cold breath effect over a video
I can render a basic smoke simulation in Blender but I was wondering if anyone knew of an approach for creating a convincing cold breath effect? Is it the same basic principle as a smoke simulation but messing with the physics etc?
I'm not sure how to see the video so I can position exactly frame by frame a simulation either.
I can't find anything on Google but even pointing me towards a tutorial would be very much appreciated.
Thanks in advance.

You could do it using breath made from smoke, but it might be challenging matching up all of the elements. Not simply in terms of footage, but in terms of performance and nuance of your actors.
Lock Your Picture
You don't want to be sinking in effort until you are certain of which frames you will be performing surgery on. Once your edit is locked, drop the raw frames into a 16 bit half EXR per shot. Assuming you have shot this on a DSLR or like camera, isolate your final cut from the VSE and render out.
If you have several to many shots, maintain solid control over your organization. One directory per shot, with versions as subdirectories or an alternative approach that works for you. Bear in mind that if you are performing a dissolve or an over where two shows are displayed at the same time, you will need to make sure that you have a full series of the entire frame count, including the overlapping portion, in your half EXRs.
Gather the Plates
Ideally you would have a library of plate shots, shot against black. Consider a back light to bring just enough lift into the breath to give distance between the lower black of your background and your foreground breath. You could capture these using a DSLR without much effort, assuming you can find a cold enough area to work in for a bit. Gather up many plates so that you can combine them in ways that suit the breath required in your shot. If in doubt, capture more rather than less.
If shooting is unrealistic, consider rendering out plate elements with variations using your smoke concept or gathering up found footage that might be available online with permission to use.
Alpha Technique
Use associated alpha (sometimes sarcastically referred to as the One True Alpha) on the plates based off of a luminance key pull, making sure to bring up your lower end enough to threshold out the black you are photographing against. If grading is required, make sure to unpremult the alpha otherwise you will incorrectly skew the RGB to alpha relationship leading to glowing or darkened fringes.
Tracking
Depending on the nature of the breath element, you might be able to get away with a 2D manually tracked element with an empty and some scaling. However, if you have a shot that warrants it, consider tracking it and laying in your elements as it shouldn't be too complex and potentially add tremendously to your work. You gain the ability to add subtle depth of field and possibly some depth cuing for free.
If you do track your shot, consider adding a subdivide or two to your floating plates and subtly warping them with a quick sculpt or curve. This will add some perceptual parallax as the camera moves and more greatly sell the effect.
Matching Footage to the 3D View

I'm not sure how to see the video so I can position exactly frame by
  frame a simulation either.

From the Properties panel (hotkey N) you should see "Background Image". Set accordingly. To keep your sanity, position the camera at a perpendicular position to the grid and position your elements accordingly. If you are going to attempt a 3D effect, make sure to set your camera lens to roughly what your shot was conducted on, and set the sensor size to APS-C or whatever gate size you shot on. If you are going to do a strictly 2D approach, this isn't an issue.
If you are attempting something strictly 2D, where you are using an orthogonal camera and floating 2D planes,this can be a little tricky if you aren't careful. First, make sure that your render dimensions match the dimensions of your footage. Second, if you are seeking to perfectly match a plane to the viewport, you will need to set the scale of your pla such that it matches the ratio of your frame. That is, for 1920x1080 footage, your scale would be 1.920 by 1.080. If you don't use the fractional values, you will end up triggering some cubic scaling on your images and the result will end up a blurry soup, so be aware.
If plausible, try the 3D approach for fun.
Further Reading
Here is one approach, loosely summarized above, from a larger budget production:
https://www.fxguide.com/featured/the-thing-a-matter-of-life-and-breath/

Please avoid link-only answers.  Please try to explain the contents of the link in your answer.

Updated to meet the request.


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Iron Man internal helmet effect
Does Blender cater for this kind of visual effect: https://m.youtube.com/watch?v=YD50NYOkyIg
in video files?
I can't find anything aside from Iron Man sculpture tutorials.

Of course, but it's hard work. You can search for Iron Man HUD or check out the latest making of: https://vimeo.com/66944464.

Lovely, thank you. Found this: https://www.youtube.com/watch?v=QFJESgclikQ

Related: https://youtu.be/I3DSI_BjA4g, https://www.youtube.com/watch?v=IdUH3mqe9iE


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Overlying images while tracking motion and adjusting angles
I was wondering if it is possible to do something like what is happening in the Gif's in the link below?
http://time.com/4655165/donald-trump-meme-gifs-executive-orders/
I've found a tutorial for 'flat' tracking here: Overlaying an image to cover a face in a video?
but I'm specifically looking to be able to adjust the angle of the image that is superimposed to match that of the video section it is tracking.
Thanks for your time as always.

Will this still work if some of the area being tracked has a part of the video footage move across it? What I mean is: if (like in the linked Gifs) a hand moves over the tracked area will the hand be visible and the inserted image beneath the hand?


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Atmospheric Re-entry
I'm using Blender 2.75 Cycles, I'm looking at trying to create
an atmospheric re-entry scene.
So I'm looking for a node setup to create something like this image by using particles or some alternative method. I have attempted to use the smoke simulator but the issue is my CPU is quite slow and GPU smoke rendering doesn't seem to be supported yet.

I would model the reddish smoke as a solid object, parented with the ship, move it in it's own layer, set to a new render layer.
In the compositor you can blur it, make it transparent, add some noise texture to bring some life, mask some parts to animate it .....
Fast rendering and effective results

Sounds like it could work, what would you recommend for the initial material setup? I was thinking maybe a red glass material. Also you talk about masking, I don't know what that is, unfortunately.

If it's gonna be animated, I would do a simple red diffuse material, for fast rendering. In the compositor you can create a Matte - ellipse mask, blur it, mutiply with your red smoke and animate dimensions and location of the mask, to make the smoke appear, disappear, big, little ....


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Does gpu rendering support on gt 730 ddr3 or gt730v2 ddr5?
I have an old pc core 2 duo E6550,Ram 4gb,i know this is not a power full pc.Does gpu rendering support these two graphic cards?

According to this page in the blender reference manual they claim that

We support graphics cards starting from GTX 4xx (computing capability 2.0).

I also found both the cards you mentioned in the list of CUDA-enabled GeForce products on this NVIDIA page with computing capabilities listed as 2.1 and 3.5 so I would claim that yes, GPU-rendering does supports those cards, especially the ddr5-model.


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how to make light pass through a mesh?
I see in real world some time light pass through our ears and nose,i wanted to know how to make light pass through a mesh in blender cycles?

Also related: http://blender.stackexchange.com/a/24888/3127

You will want to use the sub surface scattering shader (SSS). or the faster and less accurate translucency shader.
Here is Suzanne with a SSS shader applied, and a very bright light behind her:

The small scale causes the light to spread less far within the object. I set the radius to 1.0,0.6,0.6 to give the light the red cast.

Can you share you share your .blend file i am new to blender i don't know how to add light like you did?

@Hashir Sure, here it is: http://blend-exchange.giantcowfilms.com/b/510/

Thanx buddy,i really appereciate it


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Why can't I use branched path tracing?
Why can't I use branched path tracing?

I realize this question is old, but in case you're still looking for an answer.. Is this an official build from blender.org?

yes it is fixed now sonce i updated, but it was official


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Why is bake action creating weird rotation?
I have an object that's animated using a Follow Path constraint. Follow curve is checked. Everything works great.

BUT I need to export this animation via FBX. I'm thinking that Bake Action is the best way to do that. But unfortunately, when I try to bake the action I get all kinds of weird rotation as the object passes around corners.

Any ideas as to how I can get proper baked animation?
For those interested, my bake settings are:
[X] Only Selected
[X] Visual Keying
[X] Clear Constraints
[ ] Clear Parents (I've tried it both ways. No luck.)
[X] Overwrite Current Action

This is caused by "Gimbal Lock". To correct for it, switch the rotation mode from XYZ Euler to Quantarion and then rebake.

It turned out that this had something to do with the rotation axis; I don't understand more than that.
I was able to fix it by rotating the object, applying the rotation, and using different Forward and Up settings in the Follow path modifier.


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Rig a pre-bent curve to smoothly unbend
I have a curve. I need to somehow rig it so that I can smoothly "unbend" it at its "elbows"; I need it rigged so that I can bend it bag and forth at will.
I haven't been able to figure out a way to bend it open so that the "elbow" becomes completely vertically straight curve when "unbent"; it seems that no matter what I try it always has a nasty weird V-ish shape at the elbow even when unbent. Of course, part of the difficulty is the fact that the curve has quite a few points. Unfortunately due to the nature of the project, I have to have the curve be as smooth as it is around the elbows (it's used for array duplication of zipper teeth).
Also, due to the nature of the project, the curve's initial position is important--so I can't start with it unbent and rig it to become bent, for example.
I've included an image showing the the starting shape and the desired end shape.
Rigging it so that it can smoothly bend at the "elbows" seems like it should be so simple, but I can't seem to accomplish it. Any ideas?

The problem is that you have too many control points on the curve, which makes it hard to control.
Would be best if you could fit a bezier or bspline curve to the shape of your curve with less control points.
You can control curve(s) with vertex hooks modifiers pointing to bones. Add an armature and make a bone in every curve's control vertex location. Select bone in posemode, shift-select curve, enter edit mode, select control vertex at bone's location (or multiple points if there are many in line), Ctrl+H+Make Hook to Pose Bone.
Then pose the bones so they are straight. You can parent them into a chain and position them by rotating the parents, so the curve points move naturally in an arch.
The more control points the more tedious it is. This process can be however scripted easily.

Thanks! Yes, this is what I ended up doing. The curve was generated from the mesh (because its specific position was important) but I was able to reduce the points around the elbows and do a single hook for the top points, a single hook for the bottom points, and one-hook-per-point for the elbow points.

I'd suggest converting your curve to a mesh, then rigging it with bones. It seems like how you are moving the curve can easily just be accomplished by bones that control a mesh.


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Way to color shade selected object
Is there possibility to get color overlay over selected object (in object mode). Just like when you select something in edit mode.
Default indication is border over mesh, but this can be very unclear in some situations and you end up tab-ing into edit mode or looking in scene graph to see which mesh have you selected.

One work around for the problem of not being able to see which mesh is selected (because the  edges are blocked from view); is to turn on display Wire.
In the Properties window on the Object tab, under the Display category there are several options for different things that can be displayed in the 3D view along with the object. Check the button for Wire and Draw All Edges, then the edges will be overlaid on on mesh, which when selected will change to be the selection color.

I have created an addon called Selected Wireframe that will turn on Wire and Draw All Edges for all the selected objects. It will respect the object's wire and Draw All Edges settings, and leave the object unchanged when not selected.
Usage is simple, after installing and enabling the addon, just click the Show Wire button in the Tools tab of the Tool Shelf. Then when you do not want the wirefrmes displaying on the selected object, click the Hide Wire button in the same place.

In situations like this I find quickly toggling wireframe mode (Z) very useful:

Paste this into text editor and run it, it will switch an orange material based on your selection.
import bpy

mat = bpy.data.materials.new(name="Selected")
mat.diffuse_color = (1,0.5,0)

def sel_handler(scene):
    for ob in [o for o in scene.objects if o.type=='MESH']:
        if ob.select:
            if len(ob.data.materials):
                ob.data.materials[0] = mat
            else:
                ob.data.materials.append(mat)
        else:
            if len(ob.data.materials):
                ob.data.materials[0] = None

bpy.app.handlers.scene_update_pre.append(sel_handler)

It will override your materials though, so be careful.

Another possibility would be to draw with bgl module over viewport what is selected, but because it would be in python the performance on high-poly meshes would be superslow..

Would have written a script as well but it would be a pain to get it working "properly". This breaks when you look through the camera or select an object that you can't apply materials to. Also not possible to switch the current material with the object selected. Perhaps have it get the current material if any and push it back when the object is deselected. Messy to work with outside of simple test cases.

Yup I kept it just super-simple, the material switching is not a good idea at all, even done properly. Best would be to implement in bgl or to fork blender and do it properly.

There exists no builtin option to change the overlay color of the selected object except in object mode, at most you can change the border color in your user prefs.
One alternative is to change the object color in the Options panel under Display and then create a material and under its Options tick Object Color.
The few extra clicks is slightly a bit tedious in my opinion but you can use the same material when rendering, you just have to untick Object Color in the material settings so it doesn't interfere. This process could also be converted to a script to make it more efficient.

hmm. I don't know if there s no way. I accidentally did it once. let me check it out to see...

@VinceScalia it was with a MatCap material in previous versions of Blender, wasnt it..

@Jerryno I have no idea. it was a mistake and I couldn't turn it off.

@VinceScalia More than likely matcap before 2.71. It's not possible to change the overlay color in object mode.


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Motion blur on texture
Is it possible to have motion blur on moving texture via variable mapping location coordinates ? I am using cycles.

I am trying to have ground animated with motion blur, but don't want to change position or size of plane.

(http://i.imgur.com/b752zJX.gif for animation)

Motion blur will not work because the object doesn't move in the scene. What you need to do is to blur the texture in the nodes. For it there is nice node group named ImageBlur from the b°wide NodePack. This node will blur the image in all directions, put it between Tex. Coords. and Image Texture nodes. You can control the amount of blur:

To blur only in one direction we need to adjust the ImageBlur group node. Add those Separate RGB, Add and Combine RGB nodes and change marked values:

Now you have blur only in one direction:

If you also plug in 2 Mapping nodes with opposite values for rotation in Z you can change the blur angle:

The solution in this particular case might be using two different textures, the clean one you have, and another one previously blurred in Photoshop, GIMP or any other software.
Then, in the material nodes, mix the two textures with a regular Mix Node and animate the Factor between 0 and 1 when your mapping starts or ends its movement.
You may animate it manually, unless some math guru gives you a magic Driver setup for this.
Note that if you simply blur your current texture, it's not going to be seamless. First make a composition of 3 tiles, apply the directional blur to it and then cut the middle tile.

This is fine if the blur amount is constant (and much more efficient than the other answer which uses a noise texture to 'blur' the vectors), but if you have to show the increase/decrease of speed, a simple fade between the blurred and un-blurred texture will look bad.

You're right. If the acceleration were fast, it could be fine. Maybe another intermediate texture could improve the result.

Yep, you would need to have a texture for every frame, which you could easily pump out of blender's compositor.

Well, I was thinking about fading between 3 different textures actually. It need to be tested, but it might work.

Meant for every frame of the transition (not the whole animation), but think we're thinking the same thing basically :)


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How to fight deep creases/intersecting mesh when sculpting?
Often, when sculpting, you are unintentionally creating deep creases with mesh hided inside of your model. Here are some screenshots of a quick example.

In the real world it can happen when you model bended limbs or hair locks, or when joining 2 meshes together.
So the question is if there is a quick or "right" way to fix a situation like this? Because smoothing it "till nothing left" is not an option...

I usually just use an excess of the smooth brush at high strengths in such cases, and it works for me. Why is smooth not an  option?

Because in a particular case you will smooth the whole model until you get rid of the unwanted mesh, in case of joining 2 meshes sometimes you will never smooth it enough. For example how do you add a high poly ear to a high poly dyntopo sculpted head? Like you have some creature with lots of geometry, then you want to add a human ear and then to change the ear with sculpting. How do you do it so you can have seamless mesh?

I'd connect them with a boolean modifier or remesh, the go over the seam with a simplify brush and a smooth brush.

Shrinkwrap would work also. But with all of these, if you're working on detailed model you might have to detach the part that needs work and re-attach it later. Or you could just go into edit mode and do it manually. But as far as a "right" way, as far as I know there isn't one.

The only tool that worked for me in a similar situation was the flatten tool. I had to run it over for a long time and it did make a bit of a mess. It was almost as it kept digging the crease slowly out. The resulting mess was not hard to clean up and it got rid of the sharp crease between two joined objects, that no other option worked. I had originally the same problem, that if I used the draw brush or even the clay strips brush to build the crease up as soon as I tried to use smooth brush right after it would make the crease come right back.


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Baking pose in Blender
I have exported a model from DAZ, and I am fighting with the export options.
I would like to bring in the bones.
When I import my fbx file, it looks like this in Blender:

When I click the "Pose" icon, the model looks as I expected.

However, when I then export the model from within Blender (with "Pose" activated), the model is still as weird as shown in the first image.
I would like to understand what is happening here.
I guess it is about baking the pose, right?
If yes, do I have to bake the pose in DAZ or in Blender?


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Merging mesh parts that use the same texture and shader
I have created a model and imported it into Blender.

All parts of the mesh use one and the same texture image.
However, when load my blend file in Unity, each and every mesh part receives an individual shader / material slot:

My problem is
1) that I have to re-assign the material in Unity (well, I guess, I will sooner or later find out why Unity does not use the correct material right away)
2) that I would like to merge some parts into a single part (for example, "Face", "Legs", "Arms", etc. should be a single object called "Body" since they will use the same shader)
Can somebody tell me how I can do that?
Thank you!

If you select one part in Blender then double tap the 'a' key it will select everything. If you press 'Ctrl+j' it will merge all the parts.  Unity should now only see one mesh, material and texture.

Thank you! Do you want to make your comment the reply?

If you select one part in Blender then double tap the 'a' key, it will select everything.
If you press 'Ctrl+j' it will merge all the parts.
Unity should now only see one mesh, material and texture.


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Is it possible to parent an object and have the child retain its rigid body physics?
I made a ragdoll that I would like to use in the Blender game engine. Right now it consists of six separate objects: a head, torso and four limbs. Each object has rigid body physics and the head and limbs have a rigid body hinge constraint, and child of constraint, connecting them to the torso. When I move the torso in object mode everything follows as it should, but when I run the game engine the head and limbs return to their original position. If I parent them directly they loose their physics. Is there any way to control my ragdoll with a single object so that I can translate/rotate it in object mode and yet have it behave correctly in the game engine?
p.s. I am using an armature to control the skin of the ragdoll where each armature bone is constrained to the appropriate ragdoll object.

use the normal parenting in object mode "Ctrl+P" ,which will be neglected in the BGE  , and to add parent in the BGE use the Parent actuator with an Always sensor :


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What criteria is used to sort the outliner when "Sort Alphabetically" is off?
What Criteria is used to sort the outliner when "Sort Alphabetically" is off? The order definitely changes when I toggle that setting, but I can't tell what the order is changing to.

I may guess they are "by date". They are shown in the oreder they has been stored. On the top the most recently added object to the scene and in the bottom the first object ever created. Isn't for you the same? Did you tried with a simple test file?

For the default All Scenes filter and excluding remapping users, it becomes sorted top-down by last added. This is somewhat obvious if you disable the option and just add objects to the scene. No object type takes precedence. To make sure, also checked the source and it seems to do just that.


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Inverse kinematics bone doesn't stick to its source
When I grab the footIK.L bone in the below image, everything seems to be working except for movement of the footIK.L bone. In tutorials, duplicated bone (footIK.L) stciks to its source bone (foot.L) and when grabbed they move together.
How can I stick the footIK.L bone to the foot.L bone?
Blender file

I downloaded the file. I'm not sure about how you wish to move this ik bone. Can I see the tutorial you are following?

@m.ardito https://youtu.be/VVHKBSknFhA?t=4m15s

mmm I can't fully understand but for sure in the video (I just saw a few minutes) I see two different things: 1) he's using xyz eulers, 2) he says he duplucated the foot.L boen to Foot.IK.L so then ht IK bone "is still parented" but your IK bone is not parented to the upper bone "bone".
Then, his IK chain has also one more bone above... I'l try later...

@m.ardito Thaks for your interest. He brokes the parent relation at 1:50. Also, I have omitted the upper (fourth) bone for clarity. By the way, if we click to the red/green/blue circles and tweak, footIK.L keeps sticked.

I think that

your IK could be too short. The video you are following use another bone above that with the IK constraint.
this does not allow you to replicate what he's doing in the video: he grabs the IK target but he doesn't moves it too far from the chain.

To find out, try to

remove the IK constraint from the bone "bone"
select the bone "bone", and subdivide it (press "w" > subdvide)
now you have 2 bones above the IK target bone
select the new bone, that is now directly attached to the IK target (it should be named "bone.001"
reapply the same IK constraint to the IK target as it was before
now grab the IK target and move it around: it stays with the constrained bone.
however, if you move the IK target too far, the constrained bone can't "stay" with it and they separate until the IK target is too far...


text:
Where is Data Transfer Modifier on Blender 2.73a for Linux?
I've noticed that the Data Transfer modifier, as documented on Blender's modifier list in the docs, is not available on Blender 2.73a (at least).  It's just not there.  I can't speak to Blender for other OSes, but for Linux, this is the case.
Can anyone tell me what's going on and what I need to do to enable it?  Is it deprecated now?

The data transfer modifier is new in 2.74, you can download RC1 here: http://download.blender.org/release/Blender2.74/


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How do you assign multiple shrinkwrap modifiers to rig muscles?
I'm in the middle of porting my rigging tools from other animation software over to Blender and was wondering how to use the shrinkwrap modifier to achieve muscle deforms, such as what JP Bouza did in BlenRig 3.  Right now, I really don't know how to apply multiple shrinkwrap modifiers to a model to achieve this.  The modifier stack doesn't work in parallel (yet; this might change with the new Depsgraph, but not right now).  So, the effects of each shrinkwrap modifier cascades over to the next in the stack.
Is it s magic combination of vertex groups?  If so, how does one weight paint to each shrinkwrap modifier?

What I do for muscles rig is that I have 2 Armatures and 2 Meshes:

All muscles as 1 mesh with rig
Character mesh with rig

That means no muscle groups and no clutter in scene and character and only 1 shring-wrap modifier.

The muscle rig bones are parented to character rig with Child Of constraints. This also allows for muscle layering.
The individual muscle jiggle is controlled with 1 vertex group for soft-body goal.
Each muscle has its own shape-key controlled with muscle-rig bones.
Character mesh has only 1 shrink-wrap with vertex-group only for muscle-bulging strength.

could you add add a sample image, I only used corrective shape keys so far.


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How do I remap colors in Cycles?
I'd like to remap colours in Cycles the way one would have done in Blender Internal, such that I could take the output of the shader/material and change the range of colours to something else, say from a ramp.  This was how Blender Guru was able to change the texture map on his Realistic Earth so that the dark side of the planet had one texture, while the other did not.  Such a technique could also be used to affect the fac input on Mix Nodes, as well as parameters, such as Glossy 'Roughness'.
I've tried many things without achieving the results I desire, but I'm still new to Cycles.

for the earth night map, i used a BW night texture with emission, can only be seen where the planet is not illuminated by the sun. Works if the planet moves or rotates. but if static, you can use a vertex color map/texture as a factor

I'm not sure what you mean, as you can use a Color Ramp's output as a factor for anything, out of the box. Could you clarify as to what is not working, exactly?

for a planet rotating, the ground texture has to follow but the "night" is on the dark side, relative to light's direction. A color ramp can map the dark side but doesn't know where the light comes from, and will follow the rotation/movement of the planet.

this is not a problem if the planet/sun is not animated. just put a color ramp on your UV coordinates and use it as factor for day/night textures (or vertex color map)

What do you want to do?

It looks like what you are looking for its the color ramp node.

The color ramp node can take any value between 0 and 1 (values outside this range will be clamped to 0 or 1) in it's fac input socket.  And it will output the respective color from the gradient specified by the color swatches just like in BI.

Use the + and - buttons to add more swatches.
Use the <-> button to flip the order of swatches.
The color (and alpha value) of the selected swatch is set with the large color strip at the bottom of the node.
You can adjust the exact position of the selected swatch with the pos spinner.
The alpha gradient is outputted through the alpha output socket.

So it could, as you mentioned, be used to adjust the affect of an image texture on a mix shader (the image texture could just get plugged directly into the mix shader if no color adjustment is needed though).

damn, you're right, i just misunderstood... :)

I just tried this node setup that you posted, however it does not perform as expected 9ie: changing the blend factor according to luminance of the object/geometry itself).  What am I missing?  How does the image texture work as a factor?  Also, what I need is interactive with the shader/material output, rather than an image texture.


text:
How do you affect object transforms with nodes?
I'm new to writing new node systems, so bear with me, but how do you write nodes that affect the transform [matrix] of objects and maybe even data [vertices]?
I just need some help getting started.

take a look at the source code of the available Node based addons ( animation nodes and Sverchok )

@Chebhou funny how I JUST discovered animation nodes right before checking back here for a response. Thanks! It's amazing that someone has been at the very thing I was going to make from scratch years ago.

after doing some reading it would useful for others and as future reference to write an answer with what you find out

@Chebhou That's the idea :) But, first, I have to get my head around all of this. Doesn't look too hard, right now.


text:
Is there an Enable Frame Blending option or replacement in Blender 2.76a?
Frame blending is a very useful function to have when messing about with frame rates and timings of movies and frame sequences.  It's clear that that option is no longer available (at least, overtly) in 2.76a.  Is there a hidden switch, or is it built into some of the options in VSE's Speed Control effects strip?

maybe you can find the answer here: http://blender.stackexchange.com/questions/28226/how-to-enable-frame-blending-in-blender-2-74


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Is there a fluid simulation update/re-write on the horizon?
Blender's fluid simulation has seen very little love or significant advancement in recent times.  So, with the particle re-write and the 'nodifying' of simulations, will there be attention given to updating the code and algorithms for fluids?  Maybe even using GPU computational power?  There's a lot of much needed change coming to Blender, so I had to ask on this front.

I'm voting to close this question as off-topic because it's is a question about the development plans instead of Blender it's self.

Hi, this isn't really the right place to be asking about this type of thing. I'd recommend that you ask this either on the #blendercoders irc channel, or on the Blender Mailing lists.

There is the Manta Flow Project included on the GSOC 2014:
http://wiki.blender.org/index.php/User:Romanp/GSoC_Mantaflow_Framework/Docs
But it seems that the project has been abandoned.


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How do you calculate square root with nodes?
I'm creating my own merge functions in the compositor, but I've run into a bit of a wall. How do you calculate the square root with nodes? Would one have to write a python node to do this? If so, what would that look like?


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Mulitple point density clouds - intersecting each other
for an animation I want to create a fluffy cloud scenery (with the internal render engine)
To to this, I created severeal cloud shaped meshes- each of them got a particle system. Over that I build a bounding box mesh with a volume shader and a point density texture to drive the density of the volume. No problem so far. I get a pretty nice cloud with this setup but after adding a second one, I get bad results. They are intersecting.
I could render every cloud on a seperate render layer, but this would be a tidy task. After all I have 26 clouds.

What is the problem here? Which option is unchecked? I cant find it.
Thanks for your help

Is it possible you could upload the .blend?

Yes of course ~ I uploaded a stripped down blend
https://www.dropbox.com/s/uco29g48e4odwwf/clouds_stack.7z?dl=0

Switching the transparency mode of the cubes to Raytraced helps a little, but prevents alpha-transparency and still doesn't render volumes inside them.. Not sure if this is even possible with BI? Maybe you could try combining the particle systems and using just one large cube..

I figured out, it isnt possible and this is really bad for me. I could use a giant domain box, but I have 4 different cloud shader - from fluffy to thick.
So I need to render 4 passes and combines them later but there is a problem ~ the overlapping. I dont know how to handle it :/
Anyway. Thanks for your help.

I think you can solve this by using either one of 2 workarounds.
Scaling clouds domain by Z axis
This is kind of lazy solution, which assumes scaling domain cube of the fluffy clouds (those everywhere in the bottom). After domain is no longer intersecting with clouds in the foreground (left / right), there's no intersection.

Processing rendered OpenEXR images

Start with moving fluffy clouds (those in the bottom) with their domain to separate layer (assuming light sources are on a layer turned on in any case). Set up output format as OpenEXR Multilayer.
Render and save image. Do the same with big clouds on the left and right (so that they were moved together to the same layer).
Having 2 .exr images, you can import them in another scene, delete RenderLayers node to render only from compositor and mix clouds with AlphaOver node (make sure Channels of the image to draw is set to Color and Alhpa).

Rendered clouds (with and without black layer added for transparency demonstration):

The result is the same for both solutions


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Extending Object
New to blender. Working on 3D printed prosthetic. One hand design we have has been scaled for a client. There is a certain part that falls about 1.5 inches to short. The diameter and circumference of the object need remain the same as other parts attach at both ends, but the object is 1.5 inches too short. I need to pull from one face out to elongate it. I do not want to scale it in the Y axis as it distorts the circumference and width. Is there a way to split the object up into cross sections and just extend further down one end? Any help would be appreciated as soon as possible. Thanks!

Edge loops? try a few of those then extrude

Select the faces on the end and hit [E].

This would seem pretty trivial to do. Start by going into the properties window (on the left) and into Scene (third icon in the ribbon) > Units. Select imperial. This will allow you to more accurately move things in inches (the exactly 1.5 inches you mentioned). In Edit Mode (hit tab to go to edit mode) select (By right clicking on the surrounding vertexes. Hold shift to select many) the face(s) you want to pull (from what I gather, correct me if wrong, this is the end of something cylindrical).  Next set your coordinates to local (Dropdown right below the 3D  View. By default it says "Global") . This will let you drag facess accurately and elongate the object without skewing it. Now there are two possibilities:

You are working on a simple cylinder that you don't want to scale along an axis, because it is rotated. Go to an orthographic view from top (numpad 7 followed by numpad 5, if you don't have a numpad, go to View > Top and View > View / Persp / Ortho). Next, grab the axis of the 3D manipulator that is in the direction you want to move the faces (most probably the blue Z axis) and after you have started dragging, press and hold shift and control. You can look below the 3D view to see how much the faces move.
You are working with a more complex shape and simply dragging faces would distort it. In this case you must add geometry to the object. With the faces selected, hit E to extrude and type ".15" (without the quotes) or "-.15" (without the quotes. This will create an extrusion from the faces you wanted with exactly a legth of 1.5 inches.

I hope this helps.


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View camera vs. Perspective camera (scheimpflug optics)
I've been searching extensively through this and other forums without success about the topic.
I am interested in using a new camera model consisting of a normal perspective model, but where the image plane is tilted with respect to the lens plane (scheimpflug principle).
I can't find how to modify a normal Cycles camera in order to include such "simple" modification.
Cheers
Pep


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Empties change position on export to FBX
I am attempting to create a series of animations for a video game that must be stored in separate FBX files. The character model has several empties parented to various bones, and their locations are important to the game. I have a base file that contains the character mesh, the empties, and the armature, and all of the animations are created from that file and saved separately. For the first few animations I created, I did not use any sort of controllers. It worked fine, and the files exported to FBX perfectly, but while creating them I realized how much easier it would be to use controllers. I added some IK constraints to the legs, targeted to a few simple meshes used as controllers.
Any FBX files exported after I added these controllers were completely unusable. The scale, location, rotation, and animation of the armature and empties was changed apparently at random. I tried to only select the armature and the empties and set the exporter to only export selected, but it did not change the outcome at all. I was able to fix this by baking the armature's animation and deleting the IK targets before exporting each animation. However, any FBX file exported from the file using the IK constraints ruins the position of the empties, whether the IK constraints are actually there or not. Most of the time, they are moved to the bone they are parented to, but sometimes they move to random positions around the armature. I have experimented with it, and as far as I can determine the IK constraints are definitely what is breaking the empties. Even after the IK constraints are deleted and every trace of them is removed (as far as I can tell), the exported FBX files still have the empties in random positions.
Why are the IK constraints affecting the empties so drastically, and is there a way I can preserve their positions through the export?


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Is there a way to save strokes while painting/sculpting?
While painting or sculpting, user draws strokes. Is there a way with python to save those (with brush parameters and pressure data) and then play them back slowly also with python?
Point is to produce something like the greasepencil's strokes. These strokes save pressure and, through the layer system, the colour. That stroke can later be edited (changing the color, etc...) and animated. Is there something similar for painting/sculpting? It would allow to show a sculpting process from cube to final sculpt with custom point of view, materials, speed all of that rendered.
Here is the doc about how to sculpt a stroke : http://www.blender.org/documentation/blender_python_api_2_69_10/bpy.ops.sculpt.html. It has a Stroke parameter to be given, but how can I save such a stroke from user input?

Sounds like you are going to record the complete macro, I don't think we currently got easy solution on this, which doesn't mean anything in most cases. Record screen by Alt F3 if it can be considered as a compromise to that.

The point is to be able to play that back in the 3D animation. I know dynamicpaint, but it can't reproduce pressure effects, random rotations or jitter at least not as easy and precisely as if recorded from user input with a tablet.

If the purpose is to show how you sculpt, wouldn't it be ok to record the screen? Do you basically need an addon to show the pressure amount on screen?

The point is to animate the sculpture. A video rendered with cycles would show the cube first, slowly being sculpted as the time goes. For that, I would like to save the strokes with the used parameters to play the sculpting process back at desired speed, all of that rendered. It could also allow to redo the exact same sculpt but with another brush to compare. Recording the screen doesn't allow to have a nice POV and can't be rendered.

here there is some doc, but unfinished and I can't get how to save that stroke they speak of http://www.blender.org/documentation/blender_python_api_2_69_10/bpy.ops.sculpt.html. There is a stroke parameter to be given, but they don't say how such a stroke can be saved to be reused.

What you would be trying to record really would be the effect of the movements (sculpting) rather than the actions themselves. Because, the actions themselves have context. The movements of a pen or mouse device make sense only when in "Edit" or "Sculpt" mode.
Now, theoretically, you could respond to a set of events from the user interface and keyframe the effects of those actions to be able to "record" and "play back". But the amount of information and frequency required to do this probably would make the whole thing unusable but for small scale projects. (And in any case, you would still be key-framing the changes applied to the object by the actions, rather than the actions themselves).
But, if we are talking about keyframing mesh modifications, then Blender does already have something that could be of help in this case. It is called "Shape Keys".
Shape keys store intermediate states of a model's mesh and also allow for interpolation between these intermediate states.
The workflow to achieve this "recording" might seem a bit awkward but would consist of mainly two steps: 1) Add a shape key 2) Apply the sculpting "brush stroke".
In the end, you will have a set of shape keys that show the progressive deformation of the mesh, potentially, brush stroke by brush stroke.
You can now key frame the transitions between shape keys to affect the dynamics of the deformations and create an animation that is as fast or as slow as you like.
This would look more like morphing, of course, rather than sculpting, except in the case where you could subdivide one stroke to many different stages.
One thing that could be done to improve the presentation of the effect would be to have the mesh rotating in front of a static camera and apply the transitions when the affected side of the mesh goes off the view. It would give the apperance of more details added with each revolution without the viewer actually seeing the deformations take place.