You can copy part/s of a Grease Pencil object (Strokes and Points) as follows:
Copy/Paste

Go to the source Frame in the timeline
Ensure Blender is in Object Mode
Select your Grease Pencil Object
Change Blender to Edit Mode
Select the desired strokes/points/parts of the Object
Copy with: Ctrl-C  -or-  right-click Copy  -or-  [Grease Pencil] > Copy
Change to the destination Frame in the timeline (new or existing)
Paste with: Ctrl-V  -or-  right-click Paste  -or-  [Grease Pencil] > Paste
optionally Return to Object Mode (or continue editing)

You can also use similar techniques to copy parts of one Grease Pencil Object into another.
Duplicate
For Steps 5,6,7,8 - you can also use Duplicate (Shift-D) as follows:

Select the desired strokes/points/parts of the Object
Change to the destination Frame in the timeline (new or existing)
Duplicate with: Shift-D  -or-  right-click Duplicate -or-  [Grease Pencil] > Duplicate
Hit [Enter] or left-click in the workspace to position the new duplicate

The Duplicate method has the effect of merging the Strokes and Points into whatever is currently visible in the destination frame.


Export stl without applying boolean operation

Keep the modifiers in the file without applying and choose Apply modifiers in the exporter options , this way the exported objects will have the modifier applied but the original will not.


This looks like fun.

Plug a Musgrave texture into another Musgrave texture :).
Conect it as a Displacement
Lighting is rather important, I used this free HDRI
(optional)(Add a Dreamstime watermark)


It's clearly part of your unwrapped mesh that is projected as a plane, you can see vertices at each corner of the uv editor, you can turn on sync the uv and mesh selection by clicking the button shown in the image attached, then select a vertex at a corner, press ctrl+L to select the linked vertices, then you can go to the 3d view and unwrap that part of the mesh correctly.


Because its already snapped to the grid.

To explain: OBJ is a mesh-only format, therefor there is no object center. Just geometry and the object center is always (0, 0, 0), so there is no snapping to do.

To do what I think you're asking, you can have blender calculate a new origin (in the toolbox Origin -> Origin to Geometry), then you can snap the objects to the grid.

You may also want to split the mesh by loose parts before doing this though OBJ may be already split up, depending on the import options.


how to make blender automatically use relative paths 2.8

This is located in Edit> Preferences under the Save & Load category, then Blend Files> Relative Paths:


There is a Github project located here:

https://github.com/niusounds/Blender-Keyconfig

I followed the instructions given on that page, and I had an 1:1 navigation in Blender as in Unity.


Blender has a difficult texture mapping system.

To view an image on a 3D model, you need to do the following:

Select a mesh object and go to Edit Mode.
If the mesh has not been unwrapped, define your seams (Ctrl + E > Mark Seams) and unwrap it (U). Only the selected faces will be unwrapped, so make sure you have what you want unwrapped selected. Also, only the Unwrap choice guarantees that faces will have the same more or less spacial layout in UV space as they have in the 3D mesh surface, seams included.

Switch to a UV Image Editor while still in Edit Mode.
If your mesh has been unwrapped and there are some faces selected in the 3D Viewport, these faces' uvs should appear in the UV Image Editor. If this does not happen, make sure there is no render result displayed on the UV Image Editor.
Now you can assign an image to your mesh by either opening a new one from the menu Image > Open, selecting an already opened image from the drop down menu or generating a new image from the menu Image > New.
This image will be applied to the selected faces. However, it may not appear in the 3D Viewport yet. For that to happen you have to set your 3D Viewport to Textured View by hovering the mouse inside it and pressing Alt + Z. You can also change it the view manually in the footer.

If you try to render your mesh, there will be no image on it. The image has simply been attached to the mesh's UV layer. To make the mesh render with this image, you need to explicitly create a material, add a texture and change the texture's type to Image, set the image, change the Mapping to UV and assign the texture to color.

Yes, it is long winded and confusing. Sorry :)


It is mostly because of some lighting effects are happening in the scene. If you want a complete white background the I would suggest making the background first transparent and then adding a alpha over node in the compositer. If you want shadows as well,you can use a plane as a shadow catcher to add shadows in the scene with complete white background


Export transformation from Blender to OpenGL

I made a mistake in my comment to your question, but here is the correct version:

Also, as you have found out yourself, it is the second global_matrix that needs to be transposed.

The correct formula is:

matrix_world = global_matrix * obj.matrix_world * global_matrix.transpose()

However this only works if global_matrix is just a rotation (which it is in your case). In general what you need to calculate is not the transpose of the matrix, but the inverse. In the case of rotation matrices the inverse is equal to the transpose.

So the general case looks like this:

matrix_world = global_matrix * obj.matrix_world * global_matrix.inverse()


Convert the text to mesh using Alt+C
Switch to Face Selection as shown below

Select the face you want to remove, and choose the Knife tool to cut the part you don't want as shown below and then hit Enter:

Select the part you want to delete then hit x and choose delete Faces as shown below:

Do the same with the other faces and you will get the desired look as shown below:

Updated .blend file can be found here:


How can I restrict the rendering of a parented object without removing the parent-child relationship?

The Outliner is designed to be able to display a 'heirarchy' of information, that is, data that belongs to other data, including parent/child relationships.

To expand the Outliner heirarchy press the '+' (which changes to a '-' when clicked) next to the parent object:

You now have access to the selection, render and viewport visibility properties of the child object.

You can also press Numpad + or Numpad - to expand or collapse levels of the Outliner (while the cursor is in the Outliner) for multiple objects.

See the Outliner page in the Blender Manual for more information:

https://docs.blender.org/manual/en/dev/editors/outliner.html


Get Hex triplet for color and real 256 RGB from diffuse Color using python

This code adapted from devtalk.blender.org, convert color from blender standard active material to hex.

import bpy

#code by : brecht - devtalk.blender.org
def to_hex(c):
    if c < 0.0031308:
        srgb = 0.0 if c < 0.0 else c * 12.92
    else:
        srgb = 1.055 * math.pow(c, 1.0 / 2.4) - 0.055

    return hex(max(min(int(srgb * 255 + 0.5), 255), 0))

def toHex(r,g,b):
    rgb = [r,g,b]
    result = ""
    i=0
    while i < 3:
        val = str(to_hex(rgb[i]))
        val = val[2:]
        if len(val) == 1:
            val += val
        result+=val
        i+=1
    return result

ob = bpy.context.object
color_inferior = ob.active_material.diffuse_color

a = toHex(color_inferior[0],color_inferior[1],color_inferior[2])

print (a)


Is it possible to deselect a group while keeping the original selection selected?

Invert the selection with CtrlI
"Select" the group as you specify, with the Extend option enabled.
Reinvert the selection.

This works for many things, not just groups.


Why does the 3D view have trouble with clip start <=0.01

From my purely theoretical and limited technical knowledge on the matter real time rendered scenes (like in OpenGL or DirectX) use a Z depth buffer to determine the distance to camera of any object or vertex on screen.

That Z buffer is basically a black and white image of the screen, where for every pixel there can be a a value from 0 to 255 (black to white) for distance information. This image is then used to determine what is visible and what is not and build the viewport image. (There may be other wizardry involved for increased precision like double precision or using other color channels for more possible depth values, by my technical knowledge is limited here)

If the clipping distances (Start and End)are too far apart these 255 (or whatever) shades of grey are not gonna cut it and will not be enough for all the possible depth differences on screen, so artifacts and errors start appearing on screen, like the so called Z-Fighting on co-planar or coinciding faces, or these seemingly ghost-like edges and see-through faces in your mesh.

Now in theory changing clipping values but keeping them in sync should have no ill effects, but there are probably other variables like your graphics card capabilities, drivers, etc.

I would also like to know more about this, so if Blender developer, programmer or someone with more technical knowledge care correct me or enlighten us, I would be very grateful.


Your setup seems to be correct.

The material you want to use as mask must have an Pass Index number.

In the render layers enable Material Index

Now press F12: YOU HAVE TO RENDER THE IMAGE for this changes to update, and the compositor has the proper information to work with (Sounds simple, but this step is sometimes overlooked).

After that, the node setup could be something like this, where the ID mask index matches the index set for the eye material and is used as a mask for further transformations:


How do I fix a car door that is wavy along the edges and has weird textures

The waviness seems to be a result of a subsurf modifier. The easiest way to handle this is to simply double up the edges along the border. This should make it appear as a hard edge, eliminating the ripples where the faces are subdivided and averaged into the places you don't want them.


You seem to be referencing the cameras movement in the viewport accessible via  MMB, as said in your comment.

  Mr Zak, the Z axis is blocked only when rotating the viewport.

By default, the Viewport Orbit Style is set to Turntable. For  a less restrictive Orbit Style, set it to Trackball.

  [The Orbit style sets] how Blender works when you rotate the 3D View by default when holding  MMB.

  Turntable
  Rotates the view keeping the horizon horizontal.

  This behaves like a potter’s wheel or record player where you have two axes of rotation available, and the world seems to have a better definition of what is “Up” and “Down” in it.

  The drawback to using the Turntable style is that you lose some flexibility when working with your objects. However, you gain the sense of “Up” and “Down” which can help if you are feeling disoriented.

  Trackball
  Is less restrictive, allowing any orientation.

Blender Manual

To set the Orbit style to Trackball, open the User Preferences window ⎈ Ctrl⎇ AltU and go to the Input rider. Then click on the Trackball button.


Bezier Curve - Cant select anchor points

In blender select objects by right mouse button instead left mouse button. Left mouse button is used to place a 3d cursor.

If you want to change it - you can do this in file -> user preferences -> input tab. But it is recommended to stay as it is


Geometry Nodes: "Attribute Randomize" - What are the Attribute Variables?

Change from Float to Vector, then you can just type in rotation as the attribute, from there you can control the XYZ rotations.


How to import a blender python script in another?

The issue was that the path of the python module - generate.py was not in the locations where python searches for modules. To make generate.py visible to python add the following code on top of test.py

import bpy
import sys
import os

dir = os.path.dirname(bpy.data.filepath)
if not dir in sys.path:
    sys.path.append(dir )

import generate

# this next part forces a reload in case you edit the source after you first start the blender session
import imp
imp.reload(generate)

# this is optional and allows you to call the functions without specifying the package name
from generate import *


Getting interstitial compositor frames when using frame step

This does it, though it uses a separate python script instead of something automated in Blender. Use it with python3 script.py [subfoldername] [framecount].

This is based on my setup, where each render pass has its own subfolder. This will search through all the files in a subfolder, determine their frame step, and generate duplicate frames based on the gaps. None of the pass files have special names, so everything's 001.png, etc.

import shutil
import sys
import os

# figure out the frame difference
def getFrameStep(list):
    step = int(list[1][:-4]) - int(list[0][:-4])
    return step

# how many 0's should precede the number
def getFrameFilename(index):
    maximum = 4
    l = len(str(index))
    return '0' * (maximum - l) + str(index)

# generate frames based on missing steps
def framesFromParent(path, parent, step):
    starter = int(parent[:-4]) + 1
    for f in range(step-1):
        if (starter + f > int(FRAMECOUNT) and (FRAMECOUNT) != -1):
            return

        name = path + "/" + getFrameFilename(starter + f) + ".png"
        shutil.copy(path + "/" + parent, name)

# ignore OSX DS_Store files
def cleanDSStore(list):
    s = ".DS_Store"
    index = list.index(s) if s in list else None
    if index == None:
        return list

    list.pop(index)

    return list

# check if command line args exist
def checkArg(index, default):
    if len(sys.argv) > index:
        if isinstance(sys.argv[index], int):
            return int(sys.argv[index])
        return sys.argv[index]
    else:
        return default

########

# the subfolder containing the shot you want
SHOTFOLDER = checkArg(1, "1-entering")

"""
using frame step means sometimes your animation won't divide
evenly, and if you try to replace frames exclusively by the
frame step, you'll wind up with more frames than the original
animation. Set the frame count if you want to limit the total
number of files generated to 50 frames.
"""
FRAMECOUNT = checkArg(2, -1)

for root, dirs, files in os.walk(SHOTFOLDER, topdown=False):
    for name in dirs:
        for r, d, f in os.walk(os.path.join(root, name)):
            folder = os.path.join(root, name)
            files = os.listdir(r)
            files = cleanDSStore(files)
            step = getFrameStep(files)

            for f in files:
                framesFromParent(folder, f, step)

("Why don't you just use OpenEXR?" "It's a huge pain to work with in Resolve.")


Any way to create a 360 stereoscopic video for playback in VR?

Starting from Blender 2.78, there will be a 'Spherical Stereo' checkbox in the camera panel which does exactly what Sybren has described. It will pivot the stereo camera per pixel to give you always the correct stereo offset for any direction.

Read official release notes for more details.


Can OpenGL Render handle (semi)transparency of an object?

Her is whay I tried, but I don't know about your dome...


I am modelling a human, and need to split the legs

The .blend file you provided does not have the same geometry, but this should be adaptable. Select the middle edges/vertices as shown in the picture. In the .blend you provided, this is as simple as alt clicking on an edge. In your real model, it may involve a bit more finagling to get the selection where you want. You can select multiple edges/verts by holding shift and clicking, or holding ctrl to get the shortest distance between two points. You could also use the circle, box, or lasso select for this. Anyways,
delete them x > delete vertices

select a region of edges/vertices and press 'F' to fill in a face. This may be more or less difficult depending on how symetrical the front/back topology of the model is. Its the least painful when there are the same number of edges.

Not sure why those images got out of order, or how to fix them. Sorry about that.
Fill in the rest of the faces, if you need more resolution in the middle areas, use the ring tool, 'ctrl+R', or knife tool 'K' You can peel back the sides with proportional editing 'O' turned on, make sure to hide the other leg, or turn on connected only, so you don't drag it along. You could also switch to sculpt mode and use the smooth tool.
This image uses sculpt mode smooth.

This is the same process but without deleting the vertices ALL way up.
There's no one way to do things in modeling, this is your little world and you can do it however you like. That said, it would be much more efficient to make your legs split from the start, than to make them one block and split them later.


Writing contents of bpy.data.texts to folder with bpy.ops.text.save

You can find current active text object in screen.areas of text editor
area = next(area for area in context.screen.areas if area.type == 'TEXT_EDITOR')
text_obj = area.spaces.active.text

Assume that you know your text-block name, then assign that text type to active text:
area.spaces.active.text = bpy.data.texts['Text.001']

This will change the current active text object.


Blender - Some of the bones in armature moving mesh

The issue is that you have skinned your mesh before symmetrizing your rig.
Result: the newly created part of the rig isn't skinned properly to the mesh. And I also guess your mesh may not have vertex groups for those new bones.

First, make sure you have vertex groups with the same names as each deforming bone.

Then, you'll have to edit the weights of your mesh in order to assign the right side properly to the right side bones. Either use weight paint mode, either edit mode via the vertex groups pannel.


I can't find the Rendering Toggle button in Blender 2.8

You can display the options you want if you click on the key icon:


Is there an Edge Crease tool for the Smooth option (similar to that used for the Sub surf modifier)

Edge Split modifier may be the thing you are looking for?

After applying the modifier to the object you could use "Mark sharp"
to further modify the behavior of the modifier.

Hope it helps.


Blender won't import my custom module, ImportError: No module named mymodule

You can place your module into the folder blender_directory/2.68/scripts/modules/ (so Blender can found it automatically), while your addon can stay in the scripts/addons/foldername folder with its __init__.py (and not __index__.py, by the way).

Or, you can go to User Preferences, tab File, and specify a custom extra folder for scripts, in the scripts input.
Note that this custom folder must contain 3 sub-directories : addons, modules, and startup.

In this example, your addon will of course be placed in :
/home/user/scripts/blender/addons/yourAddon/,
and the module(s) you want to import will be into :
/home/user/scripts/blender/modules/.

This way, no need to use sys.path.append()!


Before you can render a smoke simulation you need to run the simulation once.

To do that go to the first frame and press AltA (or the play animation button on the timeline)

Pay attention to the gray bar being created at the bottom of the time line, it will show you the frames that have been cached.

So the key thing to learn is that the information for most simulations (smoke, physics, particles, etc) has to be created and cached first. Otherwise blender has no information to be rendered.

Also, any changes made in the simulation will require that you re-cache the whole thing.


Texture not appearing while in object mode

Textures aren't displayed in Solid view by default. You can either switch to a higher level shading view which displays textures, such as textured view (⎇ AltZ). Or you can enable Textured solid in 3D view > Properties region (N) > Shading:

Note that this doesn't affect the final render, only the viewport.

See the wiki for more information.


When I join two objects with logic, the logic from one is lost

As far as I know Blender does not support merging logic bricks. It can completely replace it via a copy command.

As mentioned by Duarte Farrajota Ramos merging meshes does not care logic bricks.

I think it is possible via Blender Python. But I do not know if anyone ever created such an add-on.


What is causing my frames to "flicker" after being rendered?

Well you have a scene lit by three sun lamps which is not very conventional, but that should not cause problems by itself.

The real source of the problem is that your lighting seems inconsequential and  the lamp placement random and not well thought out.

You lamp objects are intermittently inside and outside of animated objects. That will obviously lead to seemingly random lighting variations across frames.


Check this video, it may help:

https://www.youtube.com/watch?v=s2Df3C3_IYE


can we send vertex info to voronoi texture node to create texture

Animation Nodes can be used to dynamically generate voronoi diagrams. Storing the color information of the diagram and accessing it from the render engine is a problem and our options are limited, one option is to use vertex colors, where the quality depends on the number of loops in the target mesh.

Vertex Color

First, you should study how vertex colors works in blender and how to assign it using Animation Nodes and Python. For this, you should see  my answer here. I will be using the Vertex Sample and Vertex Colors subprograms defined there in my node trees, so make sure you implement them first.

A simple F1 vornoi diagram based on random points can be generated using a KD tree as follows:

If one wants to use custom points locations, then one should replace the random locations with the custom locations:

If you want to have a solid color for each voronoi cell, then the indices output can be used or a random number based on it:

You might notice that the quality starts to become rather low, and that is the downside of using vertex colors, they are dependent of the loop count.

The other options we have are not any nicer, but they might be suitable for some cased.

Screen Space Tracing

What we can do is make a small render engine of our own that renders the vornoi as a fragment shader and use the output in the more advanced render engine. The render engine will cast a number of rays on the mesh defined by a BVH Tree, get the location on the surface point they hit, use it in the KD Tree, and then write the output colors to an image. To write an image given the greyscale value of each pixel, its width, height and name, a script like this can be used:

if imageName in bpy.data.images:
    image = bpy.data.images[imageName]
    image.generated_width = width
    image.generated_height = height
else:
    image = bpy.data.images.new(imageName, width, height)

image.pixels = [v for color in colors for v in [color]*4]

The ray casting part is simple, align a grid with the camera orientation and location, scale it based on the orthographic scale (3 in my case), we will perform an extra 90 degree rotation around the local z axis because the grid node returns the locations in the vertically first order while blender expects a horizontally first order, the node tree is as follows:

You may see the rendered image in near realtime in the UV image editor

Now, if I used the Windows texture coordinates (Screen Space Coordinates) with a material like this:

We will get the render projected on our object, which we can then use to do what ever we want:

I created this to work in orthographic view, I will let you create the perspective version on your own.

Other methods include UV space projection, it can be done as following. BVH ray cast is used to get the index of the polygon the ray intersect, we get the barycentric coordinates of the surface point through a barycentric interpolation, we get the UV space locations of the polygon's corresponding UV polygon, perform a convex combination using the barycentric coordinates we computed before, get the pixel nearest to the result of the convex combination or use some kind of interpolation like bilinear or bicubic, write the color to it. The resulted image can be used in the UV objects space as a normal texture. I shall not explain this method, because it doesn't really have any advantages and is hard and slow to implement.


Why doesn't an Environment texture appear when the world has a Volume Scatter shader?

This is a known limitation, and it's not exactly a bug.
Because the world background is an infinite distance away and a world volume shader is assumed to be infinitely large, there is a bit of a problem. No matter how low the density of the volume is, it will completely absorb all light going an infinite distance through it.
The solution
You can use a finite object volume instead of an infinite world volume.
To do this, create a largish cube object or any shape which encloses your entire scene (or at least the part which should have fog/mist/whatever in it).
By adding a volume shader to this object, you can create a finite volume around your scene which you have much more control over. See my answer here for more detail.


How can I sub divide an equilateral triangle into many smaller equilateral triangles

I could not yet figure out how to do it procedurally or in a non destructive manner. In the meantime you can easily do it by hand.

There is an addon shipped by default with Blender called Add Mesh: Extra Objects that can activated in the User Preferences dialog

Start by opening File > User Preferences > Addons then search for Extra and activate the Add Mesh: Extra Objects addon.

Then in the 3D View press Shift+A > Add > Mesh > Math Function > Regular Solid.

By default it should already create a Tetrahedron, if not just pick it from the pulldown preset menu.

The just enter Edit Mode, select all faces, press W > Subdivide. Adjust Subdivision Number from the operator properties in the Toolshelf, or pressing F6


For Blender Internal Follow this quick step below and Save the file in UV Editor

UV unwrap the mesh.
Default material
In the UV Editor -> Click on New Image  (width x height and give a file name as(abc)) -> ok
In Uv Editor -> Image -> Save as Image F3 give a name -> click ok.
Add a New material -> In the Texture Tab click on New
Below in the Textures -> Image -> Select from drop down image saved in UV (abcc)
Switch to Texture Paint -> Now you can paint

For cycles Follow this quick step below and Save the file in UV Editor

UV unwrap the mesh.
Default material
In the UV Editor -> Click on New Image  (width x height and give a file name as(abc)) -> ok
In Uv Editor -> Image -> Save as Image F3 give a name -> click ok.
In the Material -> Surface -> Color -> Change to Image texture -> Select the created image (abc) from drop down.
Switch to texture paint -> Now you can paint.


What is the easiest way to animate beams of light in blender?

If you just need a single beam you could use a simple curve object. Make sure to set the spline type to poly if you want all the corners to be sharp and jagged.

Then add a little bevel for thickness (this can be controlled per control point with the radius value), and then add a white emission material.

After rendering, you'll need to add some blur and glare effects in the compositor. Should get you closer to what you are looking for.

Bonus Round

If you want to animate the light beam, you need to add hooks to your curve control points. Go into edit mode on the curve select one control point, then type CTRL H and select Add Hook to New object. You'll see a small empty add to the position of the control point. Do this for all the control points. Then back into Object mode, you can now animate the empties to move the curve.

I found it easier to use Proportional editing mode set to Random with a large influence to move one empty and then have the other ones affected slightly as well. I did this on each frame for 5- frames then duplicated them in the Dope sheet a number of times.


Can I change the speed of an image sequence?

It is possible by using drivers:

Add an Empty object somewhere;
In its Object panel, choose one Transform channel (such as Z Scale), type in #frame, then hit Enter to confirm. It will add a quick driver for the empty, make the Z scale value the same as the current frame number (e.g. If the current frame is 6, then the scale value will be driven to 6 automatically).
In Cycles Material node editor, move the mouse cursor over the Offset in Image Texture node, hit D to add a driver.
Open Graph Editor, switch to Driver mode, keep that node selected and you'll see the driver added. Set a variable based on the Z scale property of that Empty object. Type the expression like this: variable_name * speed_fac.

For example, in the example below, I used the variable name as var by default, and use 3 as speed factor, which means to make it playing 3X speed up.

NOTE:

It's recommended to control node-related drivers by object transform, which is the tricky part, due to the current dependency limit on nodes.
If The warning message occurs (as below), click Reload Trusted.


recalculate outside (normals) for all objects

The easiest way to approach the building of a script if you are not keen on python coding would be to perform all the tasks you need, then copy the command that shows up in the info editor and paste in a loop that iterate through all the objects.

Here's a possible code:

import bpy

if bpy.context.selected_objects != []:
    for obj in bpy.context.selected_objects: #loop through all the selected objects
        if obj.type == 'MESH':
            bpy.context.scene.objects.active = obj
            bpy.ops.object.editmode_toggle() #enter edit mode
            bpy.ops.mesh.select_all(action='SELECT') #select all objects elements
            bpy.ops.mesh.normals_make_consistent(inside=False) #recalc normals
            bpy.ops.object.editmode_toggle() #exit edit mode

Here's the script in action:


Make all paths relative for a blend file via python

This will make all paths relative and then save
import bpy
bpy.ops.file.make_paths_relative()
bpy.ops.wm.save_mainfile()

You can run this from the shell like this. This should make all paths in file.blend relative
blender --background file.blend --python-expr 'import bpy;bpy.ops.file.make_paths_relative();bpy.ops.wm.save_mainfile()'


How to make an object contain water until desired time

There are (at least) two ways of achieving this, depending on the effect you are looking for.
The simplest case is to animate the geometry towards the 'wall' and to switch to fluid at the last moment. The key here is to use the Initial Velocity of the fluid 'Flow' object to give the liquid the same velocity as the moving mesh.

Ideally you would be able to simply use the 'Source' velocity (set to '1') to derive the velocity from the current velocity of the mesh. However, testing has shown that there seems to be a bug where under some circumstances the first frame of the fluid does not pickup the correct velocity (I've filed a bug report at Fluid Initial Velocity 'Source' incorrect when enabling Inflow) but it's fairly trivial to set the Initial X,Y,Z manually.
In order to achieve this, select your mesh on the frame before the impact and determine its coordinates in World Space. If you have animated your mesh using keyframes you can determine the location simply from the object's coordinates in the properties panel (N). However, if you're using, say, a Rigid Body simulation, you can determine the coordinates by first snapping the 3D cursor to the location of the mesh (select the object, press Shift+S, select Cursor to Selected) and view the 3D cursor coordinates from the 'View' properties panel :

Similarly determine the coordinates of the mesh at the point of impact and subtract the previous frame's position from it - the result is the X,Y,Z velocity of the mesh at the point of impact - use those to set the Initial X,Y,Z of the liquid.

Now either set the Flow Behaviour to Geometry and set the simulation to start from that frame or set the Flow Behaviour to Inflow and keyframe the Use Flow to switch on the inflow on the frame of impact and off again afterwards. Note that using the Geometry method is slightly better as it will give you a precise volume of liquid but the Inflo method is better if you need the fluid simulation to begin before the impact (note that fast moving objects will create more fluid as the simulation will create enough fluid to 'fill in' the motion between one frame and the next).
By now switching visibility of objects and the fluid at the relevant points in your animation you should now be able to animate the mesh turning to fluid on the point of impact :

Blend file included :

The more complicated solution is to have the mesh behave as liquid before the impact, staying together as that shape until the point of impact. The reason this is more complicated is that there is no simple method of keeping the fluid within the mesh until released by the impact - so we need to fool Blender into producing the effect using other means.
To achieve this, we'll use an Inflow (instead of Geometry) to generate the fluid as before - and also use the Initial Velocity to set it's velocity (in this case we can use 'Source' to set the velocity based on our object since it is a continuous Inflow so doesn't seem to suffer from the same bug).
In order to keep the fluid within the mesh we need to use an Outflow to remove everything that is outside of the 'inflow' geometry (the Inflow continuously adds fluid while the Outflow removes anything that isn't within an Inflow). This can be easily achieved by duplicating the Fluid Domain object and changing the type to Flow and Outflow. The Outflow should be 'enabled' until the point of impact.
Then, at the point of impact, we simply 'switch off' the Outflow and, a frame later, 'switch off' the Inflow - by animating the 'Use Flow' property. The resulting liquid should be moving at approximately the same speed as the mesh (there will be some difference as the fluid only takes on the Initial Velocity where it is new fluid added into the Inflow mesh - existing fluid is not affected by the Initial Velocity).

Blend file included :


Added twist offset option to the bridge tool r58609 (will be available in 2.69 or any recent build).


You can use the texture image as a grid. In case you have no image loaded, create one. Then activate Snap to Pixel in the UV's menu. And when you move the UV vertices around in the UV Editor, then they will snap to the pixels of the image now.

For the other questions i would suggest to open other topics.


Why is Ambient Occlusion creating this extra light? (Eevee) (Includes pic)

I don't think that there is much you can do. To me, it looks like that large amounts of light in your scene are reflecting off objects onto others. What ambient occlusion does it it doesn't only let light fall from the lamp to the object, but it can bounce off objects onto others. This bloom effect might just be light bouncing off the wall onto other (probably reflective) materials.
Just know I am not positive, as I am just basing my prediction of the picture.
Some things you might be able to do is fiddle with the roughness and specular values of the object. Specular values would probably be better, as they break the rules of light physics.
Hope this helps.


Alpha channel set to below 0.1 results in invisible object

Shaders typically have a clipping value set for low alpha values. If the alpha is below the clipping threshold, the pixel won't be rendered. This is an optimization which helps speed up rendering and can help give sharper transitions on textures with transparency.


How can I model the crevasses in this low-poly sphere?

The Cell Fracture add-on would be a good start.
(The Cell Fracture add-on comes with Blender, all you have to do, is activating it via Menu -> Edit -> Preferences -> Add-ons)

Create a sphere (icosphere or rounded cube work best) with a decent polycount.

Initiate Cell Fracture via F3 - Search - Cell Fracture.
In the settings dialog under "Own Particles" - "Point Source",
change the Source Limit to 50 and under "Recursive Shatter", change
the Recursive Subdivision to "Big" and hit "OK".

Hide the original sphere, then select all objects with "_cell" in
their names.
Go to the "Transform Options" dropdown menu and check "Locations".
This will provide us with the option to "explode" the individual
objects away from their origins, which in our case is the center of
the original sphere.

Hit S and scale the selected objects, until the desired
gap size is reached.

You can then unhide the original sphere and proceed from there with
additional modifications (decimate, boolean, etc)


What is the best topology for this odd shape?

Version 1: Low poly.

This is topology which is focused on small amount of polygons. Edge Flows aren't so good and using Proximity Loops will be pretty hard, but nevertheless both methods are working best with Bevel Modifier (Angle) + Subdivision Surface.

Topology:

Result:

Version 2: Edge Flow.

This method is focused on proper Edge Flows. You can use here Proximity Loops to sharpen edges but as stated in Version 1 it's better to use modifiers.

Here we need to use two ngons to stop inner loops before 'big circle'.

Topology:

Result:

How to make it.

I will not create whole step-by-step answer here as methods used was just Blender 101 modeling. I've started with outer Circle then created another one in the middle, scale it to have egg shape and from there it was just manual Extruding, Moving, Joining etc. I've also used two add-ons here: LoopTools > Space and F2 to speed up my work. They both are built in in Blender, you will just need to turn them on.

Notes.

My model is pretty uneven as I was modeling it 'by hand' with distorted reference image. If you have good .svg shape, you can import it and use it edges to snap vertices to them.

Blend file.

Here is my blend file. You can check different layers for both versions, also you will be able to see detailed values for modifier I've used.


Why will 'Copy Rotation' constraint make this object point in an unexpected direction?

From my experience, unless you have a good reason to use the Copy Rotation constraint, it is best to parent the object in question to the armature. If, as I believe to be the case here, there's no need to deform the mesh (i.e. all movable parts are separate objects), you can use the Bone parenting mode. Using this mode will make it so you're not required to use weight groups, which are irrelevant if the object is not to be deformed but only transformed.


Creating Volumetric lights from a mesh in cycles?

Set the light inside the object and bring up the intensity.

For the world Volume add a volume scatter node. (usually the default value of one is way too high, set it to a smaller number)

(click on the image to enlarge)


I quite didn't understand the meaning of your Heat map so I created a not-so-complex procedural material, which would consist of 3-4 nodes based on your heat map.

1] Depth Map : This map is based on height, if u want this kind of material then use the top three nodes
nodes

2] Fake Heat Map : This is a fake heat map based on distance from the
camera, a very common filter.

Ahh! I nearly forgot, you can also use the layer weight node to get
the faces facing the camera. Like This :


Moving hair system with armature control

Armature modifier must be higher in stack than particle system...also in particle settings-emssion-source check use modifier stack.


Is there a way to control the Alpha of the Freestyle lines by Sun Direction?

You can fake it with the Distance from Object modifier.
The distance from specified object will then control the transparency.

How to:
1) In your Freestyle Line Style go to the Alpha tab and add the Distance from Object modifier.
2) Set the Blend mode to Subtract
3) Set your Target object. (from which the distance will be measured)
4) Set Min/Max Range for best result. (or use the Fill range by selection button)
5) Done.

Line Style setings

Result


I tried your file, and noticed the "obstacle" (which has unapplied scale, as the domain and fluid too) was really a high detail mesh... but had 2 "geometry creating" modifiers not applied:

a solidify to give depth to your pumpkin shape
a catmull clark subsurf (level 4!) to smooth it out

that gives over half million polygons...

(note I uploaded - valid - images but atm I they don't show up... I guess imgur.com has issues... I'll fix this later if still needed. edit: now they seem ok.)

in order to check the mesh as the simulation could see it, I initially applied the solidify modifier, and inspected the resulting shape with the 3d print toolbox tools ("check all") which gave a lot of issues, and you can easily see that your solidified shape has many badly topologized surfaces (due to the modifier).

It does not seem that bad, at first glance, but since you later add a c/c subsurf (level 4) to this, the bad surface just becomes more smooth and detailed, but if you disable the c/c subsurf modifier, it is easy to spot several part of the mesh that have that bad topology

this kind of (resulting) mesh issues can easily give bad fluid sim results, imho. I would try to

remove the subsurf
fix topology after applying solidify
test the fluid sim with this simplified and fixed mesh

and/or practice with a much simpler obstacle mesh (think of a basic cube with a simple square hole), to be sure the simulation is correctly working with that, and only then, replace the obstacle with something more complex (but with good topology).


Why am I always zooming at center of grid?

If you mean your 3D Cursor, then the shortcut is Alt+Home. Otherwise, if you want to zoom into your mouse, then you should activate the option in File -> User Preferences -> Interface -> Zoom To Mouse Position


Blender render engine is rendering just part of an object

As pointed out by @rcgauer in the comments, it is a duplicated => post Where can the viewport clipping parameters be changed?

I just changed the end clip property in the View group as suggested by @adhi post linked above and it worked fine.


If you want to make something with hard surface such as a drum as referred in the question and don't want any deformation or bending( as in the muscles should get deformed when a human figure folds hand) of things while changing things then you should see in parenting things to empty so that the things get manipulated when you move empty and you don't have to move the hold thing and then finally constraining the empty ( constraints are used when you want to limit things, for example if you want to move the drums which are attached on the outer edge you'll only want to move them on their local z-axis so that they seem attached to inner drums, then you can limit its movement to only local z-axis by constraining or when you want to make something controlled by another thing for example moving drums with empty which is constrained on the particular axis giving you flexibility to move drums separately anywhere you like but still can be controlled on the important axis. ) On the other hand if you wanna create something like a human figure and want to move it then you'll have to create a rig which can control custom part of mesh and keep it look attached, this can further be combined with constraints for example, limiting the rotation of hand only in forward direction and not allowing it to go further, you can also constrain a joint to an empty so that you don't have to move the joint and can just use empty to modify the same thing which is non-destructive as you can reset the empty location or even delete that constraint completely. The best way to go is to learn rigging and rigging your drums then you can learn constraining and constrain the rig to be organised, here you can even use an empty to instead of bones,  both constraining are rigging are really wide and also work best if combined.


Extruding outward from center point to create the Bottle Cap Grip

Extrusion:

Way 1:
Select the faces, hit "e". Rightclick immediatly afterwards (that creates the extrusion but doesn't move it). Then hit "s" and "shift z" and move the mouse to scale them outwards.

Way 2:
Hit "i". Move the mouse to scale the new faces the same size as the original one. Now press & hold "ctrl" and move the mouse.

Further adjustment (optional)
Set "individual origins" and hit "s" to scale them smaller
Bevel
Hit "ctrl + b" to bevel them, use mouse drag + mouse wheel to adjust number of steps (roundness) and shape.


You can use a human mesh with a shrinkwrap modifier on a plane. Let me show you an exemple:

First if you want to use an human body you can create it with makehuman and import it in blender with all the skeleton. Then you can create the animation of your human.

After that you can add the surface where you want your silhouette to be. For the exemple I used a plane.

Now you can add the shrinkwrap modifier on your human.

Now it's time to render. I've done the render with cycle, in blender internal you have problem with the superposition of the mesh like this:

So here is the final render with cycle:

Here is the video example on youtube.

And of course it works with animation. Hope this can help you.


Copied and pasted a working fluid simulation objects and settings to another blender file but it does not work

After looking at your files, I think I found the main problem: In the working.blend, you don't have any units specified in the scene tab. In the not_working.blend you use metric units. If you change that back to none, the water will leave the tap again. Simulations depend heavily on the scale of the environment, so be sure to not touch these settings after successful simulations.
But some things still seem to be off, compared to the working.blend. If you want to be sure, I'd recommend to make the final simulation in the working file. After the simulation is done, select your domain and choose File > Export > Alembic (.abc). Specify the frame-range, check "Selectet Objects only" and click export alembic.
You can now import the resulting .abc file in any other scene. Alembic only exports the fluid mesh itself, you won't have any chance to alter the simulation.


Viewing scene render (hidden and unhidden) rather than hide in viewport

Enable both restriction toggles.

Disable in Viewports
Disable in Renders

Two options

Change or Keyframe them both.

Add a driver. Go to the Edit > User Preferences and enable Auto Run Python Scripts.

Add a driver to the Viewport Visiblity property, by clicking on its screen icon with a right click an choosing Add Driver. In the drivers popup (or in the Driver Editor), set the Type to Scripted Expression, enable Use Self and enter the Expression self.hide_render. This will change the value of the Viewport Visibility property to whatever value the Render Visibility is changed to.

It is now "connected" to the Render Visibility via the driver and any changes of the Render Visibility will directly be copied on the Viewport Visibility and be visible in the Viewport. (This also works for keyframed values.)


How to make two alembic Mesh Sequence Caches working together

Blender Sushi Guy here, I encountered the exact same situation today. And I think I have a solution that is using Sverchok nodes, but easily translateable into Drivers or Python code solution. I think Dr. Sybren can help :)

So, I have multiple alembic cace file, each for 1000 frames. I broken down the Alembic sequence into multiple caches because 10000 frames == keeps crashing Blender.

Anyhow, just like what you are trying to do, you want to "mix" the Alembic cache together, using Modifier stacks.

Ideally, there should be a mechanism in Blender allowing to do this. Maybe Blender devs are still working on it(?).

For now, I am using this "simple trick" that is basically triggering the "show_viewport" ON and OFF as needed.

I have 2 caches here, cache A (frame 1-1000) and cache B (frame 1001-2000). You can have more.

Both has "Override Frame" turned on. So we will be controlling the frame using "Time Frame". That part is taken care of.

But as you mentioned, once you stack multiple cache, the second will completely override the previous.

However if you control the "show_viewport" and trigger ON and OFF at the right time (in this case I am using nodes logic to check frame number, if frame number is bigger than > 1000, then 2nd cache SHOULD take over and continue the cache. Otherwise, it should run the 1st cache first.

Let say we have 3,4,5 cache, we can use similar logic.

I test a quick OpenGL render and seems like my cache A and B mixed together into the same mesh.

I wonder what Blender Devs working on Alembic can say about this.

But that is one solution.

Perhaps "Use Modifier During Render" (the camera icon) also needs to be triggered.

The easiest is to use Drivers, for this. In my case, I am relying on nodes.


It looks as if you already used a cube with subdivision surface modifier to get your sphere. While not a bad idea, i'd recommend to use at least subdivision level 4 for a cleaner sphere, otherwise it's not really as spherical as you'd want.
Thanks to Trey Harper for pointing out the cast modifier, i barely use, which in this case though really improves the result.
That said, going from your (cube)sphere:

Apply the subdivision surface modifier on your cube(remember lvl 4, for a more spherical sphere) and a cast modifier with the factor of 1:

Marked red, important before going on is to apply these modifiers in order!
Go in front view Num 1, activate edit mode Tab
and x-ray mode Alt+Z, select half of the sphere like this:

when selecting, leave the center deselected to keep a half
With the selection, press X and choose Vertices
In the Object Data Properties we need to activate the Normals>Auto Smooth:

Auto Smooth is needed for the next step to look clean at the cut
Go back in object mode Tab and add a solidify modifier.

Adjust the modifier to your needs and you have one shell done.

You can now copy Shift+D the created shell and adjust it's size to gain the other layers of the planet.
Here a little visual demonstration:

The thickness of each layer can easily be adjusted in the modifier
As the core looks like a full sphere, you should have all needed means to your cause now.
Happy Blending


Is Blender able to make complex night skies with stars and galaxies?

Ok, so here it is. Here's my attempt at your shader. I'll just let you take that all in. It's not perfect, but it's getting closer to what you're looking for, and hopefully the breakdown will help guide you in your own shader making adventures.

So, I think I'm going to go ahead and name this one "A whole lotta noise", because, as is the case with many procedural shaders, it includes a great deal of noise textures. It is my task throughout this breakdown to help you make sense of all of them.
Let's start with the obvious - a stary sky is going to need stars - lots of them. Big, small, bright dim - the whole deal. So, leet's make some stars. I see from your image that you have that part down pretty well, but regardless, i'll walk through the apporach so others reading can follow as well, and maybe you can combine our two styles in your final shader.
I got my initial star shapes by combining a Voronai Texture with the randomness set to 0, with a White Noise Texture. This special little combo yields "Cell noise" otherwise known as pixellated squares of varying brightness. I chose squares, because it was an easy way to get a lot of stars, distributed the way I want. The fact that they start square doesn't matter so much, because they will be small, blended with other things, and I have plans to blur them slightly later on as well in the compositor. So, In my mind, squares are fine for now. To get a more varied look to the stars, I used 4 different White Noise Nodes of different scales.
However, the result given by the White Noise is mostly on the light side (not very star like) so I clamped the values with a ColorRamp. I clamped it rather tightly because the initial map yields too many "stars", so I clamped even most of the grays, leaving only a small amount of white with just a tiny bit of variance in grey levels that I take advantage of in the next set of ColorRamp Nodes that I use to give the stars a bit of color. I didn't give any color to the smallest stars, because they are very small, and color variations wouldn't show anyway.
Lastly, I started mixing them together. FYI - all the MixRGB Nodes  set to "ADD", that are adding a nodes values to itself, is just a quick way I know of brightining the "bright" values of an image, without brightening the overall image. See below:

The next stage (actually 2 stages) was to remove some of  the extra "noise" (too many stars), by multiplying my star-maps with some Noise Textures of different scales  and distortions. I used ColorRamp Nodes to control the strength of the noise I was using to darken. This has 3 effects - Firstly, it flat out removes a bunch of the stars. this is good, because it makes the image less "noisy". Secondly it varies the brightness of all the stars that are left in the map, making them more realistic, as if some were closer than others. Lastly, it rounds off many of the sharp edges to the White Noise squares, making them more like stars and less like blocks.

Ok, so now we have a starfield, but that's rather boring, so let's add some "nebulae". Firstly, we don't want the nebula to take up the whole sky, so we have to "section off" an area for it. To do this, I used a Gradient Texture, rotated and clamped it, and multiplied it with the dark values from yet another Noise Texture to get a slightly "whispy" horizon. The reason I left it whispy is because I will be using this as both an image and a mask. I want the image to be varied in brightness, as well as a mask that is varied in opacity. Because pure white is considered "fully opaque" as an alpha value, and pure black is considered "fully transparent", I wanted a bit of grayscale variance so the transparency "blends", without harsh cuttofs - Kind of like a cloud.

I then multiplied this map with "darkness mask" I made from a Gradient Texture.  NOTE - the TEXTURE COORDINATE I am using for this particular gradient is UV, as opposed to GENERATED for everything else. I did this because it gives me more precise control over the gradient's position via the Mappong Node and the ColorRamp. I used this as a way to further "section off" the cloud. The result of which looks like this:  (FYI - The brightness and contrast values (mainly brightness) do a pretty good job of controlling the cloud size.)

Now starts the coloring section. The first thing I did was give 2 "layers" to the cloud, by using 2 different ColorRamps, one Blue, and the other Pink. The pink one I made smaller than the other by reducing the brightness (and subsequently the cloud size) ahead of the coloring. I then mixed them together, using an inverted version of the smaller "cloud" as a mask that I further adjusted with a ColorRamp to make the pink cloud "show through" the blue to my satisfaction. See below:

I then combined this with the darknes values from a detailed and clamped Musgrave texture to make it look more like a real nebula, with dark areas abound.

For the area "inbetween the stars", and to form part of the "background noise" of the universe, I combined some more Noise Textures and a Wave Texture with some bue and aquamarine ColorRamp values, using the wave to help define some of the "flow areas" to what I will now call "cosmic gas".

I also made a second set of "background-background" noise, which I mixed in right near the end, because I felt dark areas of the image were still too dark, ad were missing something in my mind. I think I could have chosen better colors, and a beter mix, but I was tired of fiddling with it at this point.

Lastly, I used a Gradient Texture, mapped, rotated and mixed with some more clamped Noise Textures to define the area of the sky where the sky background noise would effect.

Lastly, I mixed them all together - The STARS, the CLOUD and the BACKGROUND NOISE.  I ran the result through an emission shader to boost the values and the result looks like thsi (I pictured on both a plane and a sphere.) I turned on bloom as well for a slightly added effect - you can control this by the emission value to an extent.

But wait, we're not done - time for some compositing. The last step is to put a camera in front of the plane, and render an image. From there, you can go to the compositing window and play to your hearts content. I was aiming for the minimal work possible, so I just slightly enhanced the image with a Glare Node. This further rounds out the stars, and adds a twinkle". I purposely over-used it in the final image because I really wanted to demonstrate how it makes an image seem "fantasy like". Feel free to change the values to your preferences (it's largely controlled by the "threshold" value of the  Glare Node).

Final result looks like this:

I've also included the whole blend file for all those who want to play with it.
File is here -
A last note - for a real bonus, switch over to the WORLD section in the shading tab. I've left the same map there just waiting to be hooked up. Give it a try, but be warned, it made my GPU take quite a breath. Use sparingly.
All the best.


Rigify Rig moves twice as fast as the Armature Root bone after parenting everything to the Root

It looks like you might have two armature nodes where you only want one. Look into this possibility. In my experience, double transformation weirdness can often be traced to having an extra armature node that was created accidentally. This often happens by the old armature node not being deleted before trying to rebind a mesh. An armature node will be created every time you try to bind a mesh, even if that mesh already has an armature node attached to it.


Is it possible to create color patterns for many objects created from an array?

Or you can use Gradient Texture with an empty to control the center.

Use Texture Coordinate > Object
Put an empty where you want the center, and use it as target for Texture Coordinate
Use Gradient Texture > Spherical and Color Ramp


How to assign an image to Image Node by its name

you can iterate over the currently referenced images in bpy.data.images.

def get_img_reference(suffix):
    images = bpy.data.images
    for img in images:
        if suffix in img.name:
            return img

img = get_img_reference('_Roughness')
if img:
   image_node.image = img

It's possible to write this shorter but the extra checking is a sanity check. This is case sensitive, beware :)


How to create a keyboard shortcut to call a custom menu in a floating window with Python?

Just set the keymap item identifier to WindowManager.call_menu and assign bl_idname of the menu to the name property. Basic example on how create a shortcut to call a menu using CtrlW:

import bpy

class SimpleCustomMenu(bpy.types.Menu):
    bl_label = "Simple Custom Menu"
    bl_idname = "OBJECT_MT_simple_custom_menu"

    def draw(self, context):
        layout = self.layout
        layout.operator("wm.open_mainfile")
        layout.operator("wm.save_as_mainfile")

addon_keymaps = []

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

    wm = bpy.context.window_manager
    kc = wm.keyconfigs.addon
    if kc:
        km = wm.keyconfigs.addon.keymaps.new(name='3D View', space_type='VIEW_3D')
        kmi = km.keymap_items.new('wm.call_menu', 'W', 'PRESS', ctrl=True, shift=False, alt=False)
        kmi.properties.name =  SimpleCustomMenu.bl_idname
        addon_keymaps.append((km, kmi))

def unregister():
    bpy.utils.unregister_class(SimpleCustomMenu)
    for km, kmi in addon_keymaps:
        km.keymap_items.remove(kmi)
    addon_keymaps.clear()

if __name__ == "__main__":
    register()

Related: Create keyboard shortcut for an operator using python?


Texture problem, color is off in some places?

It looks like that normal map is wrong space (not tangent space).


Cycles bakes with the active (selected) UV map and to the selected Image node.


You're on the right track with sculpting. However your first priority should be to create a simple base mesh of the entire character before moving on to details like the mouth and its stitches. You can do this by blocking everything out with primitives and then joining them later.
Here's an example of stylized base meshes (Credit to VeryHotShark on Gumroad):

A great habit to get into is to focus on the largest details first so you can get your proportions correct and ensure you have the best topology possible to start out with before detailing and sculpting.

Hey guys Im trying to make a Jack Skellington blend and I have no idea how to sculpt his mouth, nothing feels right should I just draw his seams on the texture or actually sculpt them

To directly answer your question about the mouth, it all comes down to how detailed you want your mesh to be. How close you will be featuring his face on camera? Are you animating his face? Does he talk?
It might be easiest to just draw the seams on the texture, but you will have less detail than if you had sculpted it. If you sculpt the seams, it will look quite a bit more realistic and hold up better in close up camera shots.


Particle System Removes Landscape when it is rendered

Go to the Outliner and click on the Filter settings. Make sure the Render icon is highlighted (camera icon) that will let you see if anything is hidden in render. If you see next to your landscape that there is an X on the camera (render) icon, then you know it's been hidden in render.


There are strange lines that appear on my glass in my phone render. How do I get rid of them?

Your model has very bad topology (N-gons) and that's the problem of the artifacts in render (but you can see problems also without rendering, check my screenshot)

more info:
What is an Ngon?
If you're unfamiliar with what an ngon is let's go over a very quick review so you can understand this question a little more. An ngon is a face or polygon that is made up of five or more sides or edges connected by five or more vertices. Anything over a quad (4 sides) is considered an ngon.
More here (https://www.pluralsight.com/blog/film-games/ngons-triangles-bad) and on youtube/google if you look for ngons.


Is there a way to set specific dimensions in inches or an other measurment?

I expect the easiest way is to use the measuere it addon. This is included with blender so you just have to enable it.

In edit mode, select two vertices on opposite sides of the hole. Add a measure segment. Scale the mesh until the measurement shows the size you want, holding ⇧ Shift while scaling will allow for more precise adjustments. You will want to make sure the objects scale is 1.0 to get correct measurements. After you have resized the object, you can delete the measurement.


Can't bevel an inverted edge using bevel tool

I found the problem, mesh had too much double vertices.
Went into edit mode (TAB), vertex selected, selected all vertices (A) and W (Remove Doubles).


Just subdivide the mesh. It will create a new edge in between all edges.
From a single subdivision, a 10 by 10 grid will become 20 x 20.
Select all edges (press A).
From the menu, select Edge > Subdivide

Or you can do this from the context menu. Press the right mouse button and select subdivide


Add-on Dev: How to iterate the properties of a type and read/write values

You can iterate through the annotations to get and set each prop.

>>> settings = C.scene.my_addon
>>> settings.__annotations__.keys()
>>> for p in settings.__annotations__.keys():
...     getattr(settings, p)
...     setattr(settings, p, True)


How move polygons along the normals with Animation nodes?

You can use the “Polygon Info” node to access each node's normal and then  pass it through a “Translation Matrix” into the ”“Transform Polygon” node.

The Polygon Info's center output can also be used in calculations regarding the translation distance, e.g. the distance to an Empty or the angle from the torus' center.

BTW: Animation Nodes includes a “Transform Individual Polygons” template which adds the underlying node setup of looping over all polygons and outputting the mesh. You then just need to set up the transformation matrix.


Assuming you are talking about the viewport layers you see in the header:

Then just press M with the appropriate objects selected and click on the layer(s) you want them to be visible on.

Another method is to use the properties window, object tab, relations pane; the object will appear in one or more of the layers represented here by activating the button. The relations pane is illustrated in red, and in the image is in the default position.


You can press U > Unlink Object+Data. The object's "data" is the mesh itself. Multiple objects can use a single mesh, so that editing one will update the others (they're "Linked")
You could also go into the Object Data tab and manually select different mesh data for the object to use:

The 2 on the right indicates that that mesh is being used by two objects. Clicking on the 2will copy that mesh and unlink that object from the old mesh, linking it to the new one (using an incremented name like Cube.001), the same result as if you'd done U > Unlink Object+Data
I know you already know the answer, but this is a place for the future too :)


Simply use an object with almost-zero thickness for a Boolean difference.
That will get you a clear cut, with 'filled' holes.
Using a 0,01mm thick plane for a Boolean difference


sound_bake by script : unsupported audio format error

So here's the trick : Blender internally use relative paths but provides a function to convert it to 'absolute'.

In my case, I just had to add the line :

absolute_path = bpy.path.abspath(s.file_path)

Thanks again Simon


Best begginers tutorials i know are at gryllus.net after finishing all tutorials in there you can just pick some from blender tutorials. As for enter-able buildings: just move pivot point to the edge of door so you can rotate around it, and animate it so it will look like door opening.
Example:


Blender 2.8, Viewport objects visibility

Select the object in question, go Edit mode, flip normals and leave Edit mode.
Check "Clip start" and "Clip end" of the View port camera (which not visible
as an object...it is simply "there" :) ) which settings can be found on the right
side pane und View->View top most second and third entry.


Combining mesh from skin modifier to manifold object

Instead of decimate, try the re-mesh modifier.  The re-mesh modifier should be able to handle all of the hair strands and their intersections.  It should act as a global "boolean union" like you want.

If this doesn't work, you could remove the boolean modifiers, export it to a STL file, and then run it through https://modelrepair.azurewebsites.net/ I've had a LOT of luck with this tool.


Convert a partial loop of faces to an edge ring with python

This might not be the most elegant way of doing it but it works.

Also, I added a lot of extra stuff to account for odd situations, for example: when you have a partial loop of faces that suddenly changes direction (like an "L").

The point of all this was to integrate it into a bigger context sensitive tool that splits/subdivides your selection with a single edge loop and selects it (regardless of what your initial selection was) and that I can call with a single hotkey.

Next step... Modal operator!

Here it is:

import bpy, bmesh

context = bpy.context
ob = context.edit_object
me = ob.data
bm = bmesh.from_edit_mesh(me)

sel_mode = bpy.context.tool_settings.mesh_select_mode[:]

vert_sel = [v for v in bm.verts if v.select]
edge_sel = set(e for e in bm.edges if e.select)
face_sel = set(f for f in bm.faces if f.select)

#FACE MODE
if sel_mode[2] and len(face_sel) > 1:
    #Store the selected loop of faces as an edge ring
    contained_edges = edge_sel - set(e for e in bm.edges
                            if e.select and (e.is_boundary or not all(f.select for f in e.link_faces)))

    #Store the border loop of edges as well
    bpy.ops.mesh.region_to_loop()
    border_edges = set(e for e in bm.edges if e.select)

    #We're have to do some extra stuff just in case we only selected a partial loop of faces
    #or a partial loop that changes direction
    bpy.ops.mesh.select_all(action='DESELECT')
    for e in contained_edges: e.select = True

    #Extend and store the full ring because (contained_edges) is missing the first and last
    #edges of the ring if you only selected a partial loop of faces
    bpy.ops.mesh.loop_multi_select(ring=True)
    ring_edges =  set(e for e in bm.edges if e.select)

    #Extending the full ring gives us some corner edges we dont need if we changed direction so lets get them!
    bpy.ops.mesh.select_mode(use_extend=False, use_expand=False, type='FACE')
    bpy.ops.mesh.select_mode(use_extend=False, use_expand=False, type='EDGE')
    corner_edges = set(e for e in bm.edges if e.select).intersection(border_edges)

    #Update our ring edges. Still just in case we had a partial loop of faces
    ring_edges -= corner_edges

    #Lets just create a new Set at this point and do everything we need in one line. It works though!
    final_ring_sel = (border_edges.intersection(ring_edges) - corner_edges).union(contained_edges)

    bpy.ops.mesh.select_all(action='DESELECT')

    #Subdivide the final ring
    new_edges = bmesh.ops.subdivide_edges(bm, edges=list(final_ring_sel), cuts=1)

    #Select the new edges we created and extend the loop because there's a missing edge
    #whenever we have a corner
    for e in new_edges['geom_inner']: e.select = True
    bpy.ops.mesh.loop_multi_select(ring=False)

bmesh.update_edit_mesh(me)


how to distribute objects in a constraint offset integer value?

Use fixed position offset factor of follow path constraint.

For a follow path constraint with fixed position set, then 0 is one end, 1 the other, 0.5 half way along etc.  Related https://blender.stackexchange.com/a/72682/15543

Using this we can thread objects onto a curve.

Code edited from https://blender.stackexchange.com/a/93441/15543

Demo run , cone, suzanne and cylinder threaded onto a path such that there are 10 items equally spaced. Curve follow is set to False

Test script (Targeted to blender 2.8+). Select the object(s) you wish to thread on the path. Select the path last to make it active object

Edit the res = 10 to have more or less items. Change cyclic to True if the path is a cycle. (Note in link above code tests for this)

Constraints are using default settings for follow and up axes. The location of object copies is set to zero to thread them on the path.  _If making this into an operator would make these properties

import bpy
context = bpy.context
scene = context.scene
curve_ob = context.object
obs = [o for o in context.selected_objects if o is not curve_ob]

res = 10
cyclic = False
new_obs = []
o = 0 if cyclic else 1
pts = res - 1
for i in range(pts + o):
    s = obs[i % len(obs)].copy()
    s.location = (0, 0, 0)
    fp = s.constraints.new(type='FOLLOW_PATH')
    fp.target = curve_ob
    fp.use_fixed_location = True
    fp.use_curve_follow = True
    fp.forward_axis = 'FORWARD_Y' # 'TRACK_NEGATIVE_Y`
    fp.up_axis = 'UP_Z'
    # calculate the offset factor
    fp.offset_factor = i / pts
    scene.collection.objects.link(s)
    new_obs.append(s)

Should you wish to remove the follow path constraint on copies

# remove constraints
scene.update()
for s in new_obs:
    sc = s.constraints[0]
    s.location = s.matrix_world.translation
    s.constraints.remove(sc)


try to create multi-files Add-on, install fail with Error: module 'bpy' has no attribute 'props'

https://github.com/JacquesLucke/code_autocomplete

Here is a blender add-on that lets you create multi-file add-ons in blender easily. Just download the repository .zip and install the add-on. Next enable it. Now in the text editor click view > properties You will now see a couple new panels one named Addon Development then you will see a text box. Simply type in the name of your new add-on and click the button that pops up that says new addon multi-file Once this is done it will create a multi-file add-on automatically for you. Remember to click save all filesoften and also when you load blender back up and want to work on your add-on again just click the eyedrop tool and you will see a list of all the add-ons you are currently working on and click the one to load and it will. Hope this helps :)

Also in operator_add.py do you have import bpy? Maybe thats the reason?


Cycles Render without Shading (only texture and albedo)

I'll show you two solutions:

mix the Transparent and Emission shaders with the Is Camera Ray of the Light Path node as a factor

do the same as above but without Transparent node and uncheck the Shadow checkbox in the Cycles Settings panel of the Object header


My issue was incorrect normals, I used ⇧ Shift + N and it solved the problem.


Problem was Solved,
The .fbx file was all fine
In Unity I Created a new Material and Dragged my Texture file,
from the UV Editing onto the Albedo of the Material.
After That the Colors will be wrong, so you need to change some settings of the Texture.
Compression => None,
Filter Mode => Point(No Filter)


Why can't I just apply the material to any object I want and adjust
the material's scale universally to all objects with the same material
using the "Mapping" Node?

Because the UV maps of the objects can be anything. They can differ in size even on different parts of one object.
Unwrap UVs at the same time
In order to have uniform scale of UVs you can select multiple objects, go into edit mode(2.80 now supports editing multiple objects at once - that's new), select all and unwrap them all at once. If the scale of the objects is applied for all of them, you will get UV islands that will match in scale for all objects as much as it's possible.


How to pick good keyframes for motion tracking?

I don't think is about having an ideal keyframe but a range of keyframes that have proper tracking information.

You'll get the best tracking out of images that have recognizable, unique features, and those features stay recognizable from frame to frame so that the trackers yield low errors. Blurred images, low contrast or flat colors make for bad tracking. Also bad for tracking are repetitive or similar patterns where the tracker might lock to the wrong place from frame to frame.
For 3D tracking it's better if the tracked image that has translation movement and parallax

So, to determine the range of keyframes to be used to successfully solving a scene, you should consider:

At least 8 common tracking points.

Accurately tracked features (or with a low error average)

Parallax or information that clearly describes perspective or any spatial transformation.

Don't use sections with a lot of fast motion blur or where the camera remains stationary. Avoid sections where you have a lot of evident distortions (ie lens distortions or artifacts caused by rolling shutters, compression errors, etc)

In other words: In the Solve section for A and B  select the frame range where you feel that the tracking has been the most accurate and has enough information to solve your scene.

If you are unsure, you can let Blender decide what the best part of your shot is by enabling the Keyframe option on the solve tab.

Note that the section of the video clip that will get solved is not limited by the range of keyframes A and B or the auto-selected by blender. The whole shot will get solved (if possible) using the values for lens, distortion, etc determided in the keyframe range.

Additional note:

If a tracked element leaves the frame but comes back later in to the shot, it is very important that you track both sections and then join the trackers so that blender understands that is dealing with the same element and not something new.

For general tips on motion tracking read: How can I get better results when doing camera motion tracking?


is it possible to render distant objects in lower quality?

Set Render Engine to Cycles and Feature Set to Experimental.
There will be a checkbox for Adaptive Subdivision in SubSurf modifier. This is what you want.
Blender Doc: https://docs.blender.org/manual/en/latest/render/cycles/object_settings/adaptive_subdiv.html


How to store particle locations in a list?

There is no intuitive way to do this in Animation Nodes. I proposed a system to the developer that should hopefully allow us to do this intuitively. But he is still studying it. In the meantime, I will tell you how to make such system manually.

Storing Data

Each execution in Animation Nodes is independent of the next one, and thus we can't pass data between executions. To solve this, we need store the data in some place accessible by all executions at all times, a typical solution is to store the data in-memory, somewhere in the animation_nodes or bpy modules for instance. In python, to store some data data in the animation_nodes module in an attribute called test, we can use the setattr() built-in method as follows:

setattr(animation_nodes, "test", data)

If you are still not sure how this work, you can think of it as follows. We are storing the data data in a place in memory called animation_nodes.test, we can later access this data simply by getting it from the place we stored it in, that is, animation_nodes.test. Enough about this, lets talk practicality.

Implementation

What I shall show is tracing the location of the particles in a form of splines. First, we are going to compute what is known as the initial condition, which is the initial state of the system. In our case, the initial condition is a list of empty splines. We can generate it using the Fill List Node set to Spline type, where the amount of empty splines is equal to the number of particles (make sure not to filter the particles in anyway, because we want to maintain the number of particles):

What are going to do is append the particles locations to each of those splines at each frame (execution). In an expression node, I am going to input the initial conditions and set this expression:

initial if bpy.data.scenes[0].frame_current == 1 else animation_nodes.splines

Basically, this returns initial which is the initial condition (list of empty splines) if the frame is equal to one and animation_nodes.splines (some data we are going to set later on) otherwise. Why did we do this step? We are merely resetting the splines to be empty (to be the initial condition) when the frames becomes one, that is, when the time line resets, and that is what we want, we want the animation to reset when the animation resets. Now, I am going to make a loop that appends the current particles positions to their corresponding splines:

And lastly, I am going to assign/reassign the data at the memory location animation_nodes.splines to be the new data after appending using the setattr() method we described before:

Lets recap what is happening here. At frame 1, the input to the loop are empty splines, the output of the loop is splines with a single point that has the location of the particles, this output is assigned to the memory location animation_nodes.splines. At frame 2, the input to the loop is the data at animation_nodes.splines, that is, the splines with a single vertex that has the location of the particles at frame 1, the output is splines that has two vertices, the first is that of locations of the particles at frame 1 and the second is that of the locations of the particles at frame 2, this new splines are assigned to animation_nodes.splines. So, you see that at each new frame, the splines get a new point that is the location of the particle at this frame. The result is growing splines as the time passes:

The structure we just used can be edited appropriately to suite your needs, and it nearly stays the same, get data, edit it, reassign it, repeat.


Colors look much different in solid view than the render view

The problem: When in solid view there's no way of seeing if Vertex Colour mode is enabled or not. In your case it was enabled, which means that whatever material you used when drawing was being overridden by the brown colour selected for vertex colour. That only becomes visible when you switch to material preview or rendered mode.
The solution: I'm not sure there is an easy way to revert this. I looked but can't find a switch to disable vertex colours (whether at the object or layer level), which would be ideal.
So you could switch to Vertex Paint mode, select the same colour as your material (with the picker) and using the replace tool, fix every stroke's colour. This is gonna be long and tedious. You might be able to speed things up in some cases by isolating a layer and increasing the tool radius to do a whole layer at once. Also you can select everything that has a specific material by going in edit mode and clicking Select in the material panel.
A much simpler way would be to render the solid view with View > Render Viewport Animation. But then that limits what you'll be able to use in terms of effect and lights, as they won't show up in solid view.
Good luck and basically the advice is that in the future you should draw in Material Preview mode.

UPDATE: According to the following answer, as of 2.92 Alpha, there is an option in the Paint menu to Reset Vertex Color, which should solve this problem: https://blender.stackexchange.com/a/204738/168


Is there any "Show Brush On Surface" option in sculpt mode?

Sadly this isn't currently possible in blender, I believe that for one of many reasons it wasn't included into blender, that happens with GSoC projects quite often, sadly. (Maybe why blender didn't get any projects this year, 2015). As a result this isn't possible.


Offset Edge Slide seems to behaves quite irregular. A created vertex in a corner that moves inward doesn't do so consistent with the distance of other vertices and edges, and the outward side doesn't create a vertex. (not sure how to easily change that)

But in this specific case a Bevel in combination with Knife Project might do the job:

Copy the cube object and create the edge offset by Bevel.
Select the edges you like, duplicate them, Press P and Separate by Selection to make them a separate object. Then move them over/above the original object.
In Object Mode select the edges object, then Shift select the original cube object, and (with both objects selected) go into Edit mode.
Press numpad 7 so the knife cut will be projected onto the desired surface at the right angle, in this case downward.
Apply Knife Project. In Edit Mode, 3D Viewport > Mesh > Knife Project.

Result:


Render Border's related check boxes - How do they work?

Expanding on sambler and Aldrik's answers,

Enabling the Border setting in Render settings > Dimensions enables border for the rendered image and sets the camera bounds as the Camera Border.

As you can see, in the Viewport render with Border enabled, only the part of the scene visible to the camera is rendered:

With Border disabled, everything is rendered:

Viewport border:

Ctrl+B (or View > Render border) sets region in the 3D view that will be rendered when the Viewport shading is set to Rendered (this can be toggled in 3D view > Properties Panel (N) > Render Border

(Useful for making the part of the scene you want to see converge faster by not rendering other parts)

As mentioned by sambler, the Camera Only setting does not seem to make any difference (bug?)

Rendered Border:

Using Ctrl+B or Shift+B in the Camera view will define a region in the camera that will be rendered while the rest of the camera will not (if Render settings > Border is not already enabled, doing this will enable it)

As you can see, the rendered image only rendered the border selection and left the rest as black (or transparent, if you have your render settings set to RGBA in a format that supports transparency)

The Crop option  crops the black part off automatically:

(Note that disabling the Border setting in Render Settings > Dimensions or in 3D view > Properties > View will not erase the border selections)
Pressing Ctrl+Alt+B will clear all the borders and disable the border setting in Render settings and the Properties panel.


I'm importing a model, and the whole model is joined. I'm trying to separate the model's parts

In order to seperate parts a mesh, go into edit mode on the object in question, then either right click and select seperate, open the quick search menu and type seperate, open the mesh menu in the top of the 3D viewport and select seperate, or use the hotkey [P] and select seperate by loose parts.
You can also seperate individual pieces by selection, I noticed that you have vertex groups for the different pieces, which would allow you to easily pick which parts to seperate.


Edit mode circle selected P does not show any options for separation

Until a tool has 'finished', you can't start a new one. In the case of the Circle Select tool this means either pressing Enter to 'Confirm' the tool, or Esc or Right-Click to 'Cancel' the tool (though in this case cancelling doesn't actually 'undo' the selection you made, it just ends it).


How to randomise vertex position along an axis

You can use Proportional Editing set to a random falloff.

Basically, select the vertices you want affected, press Ctrl + I, to invert the selection, and then H to hide those vertices. Now, select a vertex of the ones left, press O, to turn Proportional Editing on, and, in the 3D view header, set the falloff to random:

Then, press G, to move, followed by one of X, Y or Z, either once or twice, to limit to the axis you want. Now, use the scroll wheel to enlarge the affected area so that all the vertices are affected and move the mouse until you get the results you want.
Then, press  Alt + H to show all hidden vertices again.


Why is my alpha pass binary (just 0's and 1's) in Cycles?

You have only 1 sample set for Cycles:

Any particular sample in Cycles will return either 1 or 0 for the alpha channel. Antialiased alpha edges are built up by averaging multiple samples, some of which strike the occluding object and some which do not. Using a larger number of samples, such as 16, will fix the issue.


Blender mouse function is not working properly?

I also had this problem, and it can be fixed by simply lowering the sensitivity. Note that the reset distance is still smaller than the trigger distance, so this does not fix the problem completely, it only makes almost un-noticable and more bearable.

                     With problem                                                          Improved

The reason this happens is that the game engine, when calculating the mouse's movement, resets the mouse to the center of the screen slightly before it detects the new position.
If you do not move the mouse fast enough, the game engine resets the cursor to the center before it can detect it's movement.


Is there a photogrammetry addon or setup that works similar to FaceBuilder addon for NUKE?

There is now !

The addon by KeenTools

Here's a tutorial by CGMatter


Well...I don't know of any books I'd recommend, but I can give you a few suggestions when it comes to digital content.

A good place to start is with BlenderGuru's Donut Tutorial Series. That'll help you get a good start with Blender (learning the UI, basic modelling, texturing, rendering etc).

If you're willing to spend a bit of money, I've found the Hard Surface Modelling Tutorial Series to be a fantastic way to quickly progress from a beginner level to an intermediate one (in terms of modelling). There are a few caveats, as it has been recorded with the 2.79 UI. However, everything that they teach can also be learned while using 2.80+ (I can personally attest to that). They'll teach you the tools that you have at your disposal, many modelling techniques and workflows, not including sculpting, and the theory behind proper shading, good topology etc.

As far as special effects and animating goes, there are plenty of free materials online. Poke around StackExchange and find Q/As that are related to what you want to do. Try to focus on understanding the tools that are presented so that you may apply them elsewhere. Tutorials such as the LazyTutorials by IanHubert can help you in that aspect.

To be honest, where you want to go and what you want to focus on is up to you. To my knowledge, everything that you can learn from paid tutorials can also be learned for free or figured out on your own. What the paid tutorials do is to condense the knowledge down so that you can learn quicker and in a more organized fashion.


using Mixamo/adobe fuse, Makehuman, and blender together

Use the mhx2 importer for blender: its an addon you need for make human...works great. For Fuse, they don't import well, but do import into UE4 fine so probably just a blender thing, I do my Mixamo/Fuse touchups in Unreal and Makehuman in Blender.


I downloaded i tried your mesh. Number 1, if possible use a surface below the object. That way a lot more light bounces and illuminates it. Number 2, you might want to switch your "Color Mangement - View transform - to Filmic (instead of film". Its giving nice results over hear.


Best way to model a wavy pattern for CNC milling process?

How's this for a starting point? I took a simple grid mesh and applied edge creases to every other row:

...Scaled it down in one direction and then pulled the edges perpendicular to the creases up and down to build a crude series of parallel waves:

...Then added a subdivision modifier:

There's plenty of room for improvement, but using edges as control points made it relatively simple to sculpt a basic wavy shape without too much hassle.


For rigid body and cloth/soft body simulations there are a number of things you need to be careful of.

For the Rigid Body simulation you need to ensure you select the correct 'Shape' for the Rigid Body Collisions. The default option is 'Convex Hull' which if fine for objects which are rolling over a flat surface but since it doesn't allow for any concave surfaces (such as the indentation at the seat of the chair) it is not good for smaller objects colliding with the body. Therefore, in this situation ensure you set the Shape to 'Mesh' to allow the actual mesh shape to be used for collision. This is less efficient (since the engine needs to calculate collision for all surfaces, not just an outer 'shell') but produces more accurate results. Note that you should set this for each rigid body.

Ensure to set sufficient 'steps' in the cloth simulation. More steps will result in more time to calculate the simulation but will produce much more convincing results - especially where objects are hitting the cloth at high speed. Using a larger number of steps should avoid problems such as the fast moving object passing through the cloth or the cloth getting forced through the other geometry.

Ensure to carefully set the Collision Settings - it's very tempting to just add the 'Collision' and forget about what the actual settings mean and leave them set to the defaults or inappropriate settings. For interacting with cloth the key settings are obviously the Soft Body and Cloth settings and these consist of Outer and Inner thresholds. The Outer dictates how close to a surface the cloth can get before it is pushed away while the Inner controls how elements of the cloth that have been pushed into the surface are repelled back out of the surface. Note that you should generally avoid setting the Inner to more than 50% of the minimum depth of the mesh - ie, if the thinnest part of the mesh is 1 Blender Unit in width then do not set this to more than 0.5 - otherwise problems can occur where cloth that penetrates below the surface is effectively pushed through to the other side rather than being repelled. The 'Outer' should be kept fairly small to prevent gaps between the surface the the colliding cloth.

Note that your first issue was caused by the Rigid Body 'Shape' - set this to 'Mesh' to allow the rigid bodies to react to the actual shape of the mesh (rather than a simplified convex hull).

From the second animated example, it appears that the helmet's collision 'outer' is such that it is repelling the cloth before it even gets close enough to touch it. The 'inner' collision of the chair is then presumably repelling the cloth through the surface. You should reduce the 'Outer' of both the helmet and the chair to close to '0' and adjust the 'inner' of each mesh's collision settings to a value that is not more than 50% of the thinnest part of the associated mesh. This should then produce a more stable simulation, similar to this :

Blend file included


Change the Border Collisions setting to Collide All. And to make the smoke fall naturally, change the Temp Diff to a negative value, the lower the value (i.e. farther below 0), the faster the smoke will fall. The Density value also affects this, but I honestly don't really understand that; I assumed a higher (i.e. higher above 0) density would make it heavier, but it seems a negative value actually makes it fall faster. In the image I've also enabled Dissolve, to prevent the smoke from completely filling up the domain, but I've set a high enough value to still have time to come out of the box and fall to the floor. I've also used very low values for density and temperature difference, just to see what happened. The exact values you'll need, depend on your setup.

And here's the test animation, as promised. A bit grainy, a little jumpy and very "vanilla", but I tried to get it done fast rather than with high quality.