Is there a way to draw a pattern onto mesh and then extrude?

You may use use a Bsurfaces addon and then the Knife Project Tool. Go to User Preferences (Ctrl+Alt+U-->Add-ons) and enable it.

Add an object you want to draw the extrusion pattern on, then add a Plane (or any other object you like), enter the Edit Mode and delete it (X). In the Properties Panel (N) add a new Grease Pencil layer, then go to the Tool Shelf (T)-->Grease Pencil and change a stroke placement to Surface. Now go to the Tool bookmark in a Tool Shelf. Draw some strokes on an object (hold D, then press LMB [ How to draw grease pencil on a surface (blender 2,75)? ]). When finished, click on Add Surface in Bsurface panel. Change the settings below as you like.

Now (being in Object Mode) select a mesh you created using a Grease Pencil, then your base mesh and enter the Edit Mode. Go to the Tool Shelf-->Tools-->Transform-->Add-->Knife Project. Now the only thing you should do is to retopologize your mesh a bit.


Select your object, and go to the shading tab. Press Shift>A and then click Texture>Image Texture. Press new on the image texture node and put the resolution. (It's 1K by default, so click and drag down on the dimension values and multiply by 2,3,4,5 however high res you want it.) Once that is done, connect the dot in front of the clour input in the image texture node into the dot before the Base Colour input of the Principled BSDF node (You can connect the dots by clicking on one and then dragging it on top of the other dot you need to connect). Once that is done, switch to the Texture Paint tab. In texture paint you can press Alt>S and specify a file folder to save your image. If you don't do that and close blender even after saving the .blend file, your pianting will be lost. Make sure to paint directly on to your mesh. To paint just select a colour and start painting. The rest of the features can be learned by tutorials on platforms like YouTube.
Note: I reccomend that you watch a UV-Unwrapping tutorial on YouTube and UV Unwrap your mesh before this procedure.


This button in the UV editor is what you are looking for:


Is it possible to set the viewport render maximum resolution when using Cycles?

There isn't really a way to do that yet. You can play with the Start Resolution under the render properties panel to force Cycles to start rendering at a lower resolution, however, it will still eventually progress to a full, retina-resolution render.

Although one could argue that because of the high resolution, it takes less sample iterations to get to a visually 'smooth' image (even though each sample iteration does take longer), so you can probably try lowering the Preview Samples count.


This script will enable you to copy the text object properties from active to selected :

run the script once to register
you will find it in: 3D View -> object ->copy text properties
or  hit space and type  'copy text '

import bpy
from bpy.types import Operator  # for defining new operator
from bpy.props import *   # for operator parameters

S = scene   = bpy.context.scene
C = context = bpy.context

def text_prop_copier():

        if context.active_object.type != 'FONT':
            return False

        active = bpy.data.curves[context.active_object.name]

        for ob in context.selected_objects:
            if ob.type == 'FONT':
                text = bpy.data.curves[ob.name]

                # collect names of writeable properties
                properties = [p.identifier for p in active.bl_rna.properties if not p.is_readonly]

                # copy those properties (prop != 'body') will skip from setting body property same as active object this changes all other properties but text content

                for prop in properties:
                    if (not prop.startswith('texspace') ) and (prop != 'name') and (prop != 'body') :
                        print(prop, 'copied')
                        setattr(text, prop, getattr(active, prop))

        return True

class   tex_prop_cop(Operator):

        """copy active text object properties to selected"""
        bl_idname = "fonts.prop_copy"
        bl_label = "copy text properties"
        bl_options = {'REGISTER', 'UNDO'}

        def invoke(self, context, event):
                if text_prop_copier():
                    self.report({'INFO'},"properties copied")
                return {'FINISHED'}

def addObject(self, context):
    self.layout.operator(
        tex_prop_cop.bl_idname,
        text = tex_prop_cop.bl_label,
        icon = 'PLUGIN')

def register():
    bpy.utils.register_class(tex_prop_cop)
    bpy.types.VIEW3D_MT_object.append(addObject)
    print("register done")

def unregister():
    bpy.utils.unregister_class(tex_prop_cop)
    bpy.types.VIEW3D_MT_object.remove(addObject)
    print("unregister done")

if __name__ == "__main__":
    register()


It's not clear exactly what shape you want, so this may not be the easiest approach (it's not too bad,) but you wind up with something that probably covers the bases.

Reading top to bottom, left to right, Y in the direction shown, Z up. Pivot set to '3D Cursor', at the origin.

Starting with a 12-sided cylinder, fan-filled ends, cut in half.
In Edit Mode, select all, and GX move the mesh out a little on X, select the open loop, and E Xextrude it a bit.
Still with that edge loop selected, SX0 scale it to 0 in X.
Assign a Mirror modifier in X, with 'Clip' and 'Merge' switched on
You should now find, in edit mode, by selecting all, you can move the halves apart/together to make the shape longer or shorter
Assign a Bevel modifier below the Mirror, with 2 segments, by 'Angle', about 33, not shallow enough to catch the vertical edges.

Assign a Subdivision surface modifier at the bottom of the stack.

Now by playing with the distance between the ends, and the settings in the Bevel modifier (segments, width, profile), you can reach a wide range of objects which answer your description.

You can improve the topology a bit by CtrlX dissolving every other edge in the fans, leaving all quads


Sweep along a path through multiple cross-sections

i'll further update the answer if you upload a demo blend with those shapes. I'd like to give you a nice answer.

For now, i'll clarify what i've said in the comment, with an illustration. For predictable results I recommend making sure all profiles have the same vertex count. There are two ways to do that.

subdivide the square profile.

or, double up on the destination vertices.

notice that the locations of the vertices in this "doubled up" example will produce some undesirable twisting in the end result.

One simple way is to interpolate both UV (slices between profiles) - without a path or trajectory". Notice how the extrusion goes exactly through the profiles too.

In the above example you must position and rotate the profiles in such a way as to achieve minimal stretching. Sverchok's Object In node interprets each Curve as a list of Vertices (the vertex indices are sequential and stable from Curve objects) and we interpolate between the list of resulting profiles. Get the .blend on this issue


Motion Tracking - Link track to empty and move camera instead of empty

I did something similar to this to avoid having to do full camera solving and achieved it by converting the track into an f-curve and then using the scale tool to invert the track (scaling by -1 in the y-direction) for each of the channels. This produced an empty that moved in the opposite direction to the original footage which I could then track the camera to. This can be achieved as follows :

Create a new Empty to act as the target and add a 'Track To' constraint. Uncheck the 'Active Clip' checkbox and select the relevant the Movie Clip containing the track. Set the Object, Track, and Camera. This should result in the Empty following the chosen point in the footage.

Click the 'Constraint to F-Curve' button in the Constraint panel. This will remove the constraint and convert it into an F-Curve on the empty so we can then manipulate the F-Curves.

Select the Empty and open a Graph Editor window and make sure the mode is set to 'F-Curve. You should see F-Curves for its X, Y, and Z locations.

Press 'A' until none of the graphs are selected (each press will toggle all or none). Right-Click on the 'X Location' curve to select a point on it. Press 'L' to select all linked points (ie, the whole curve). Press 'S', 'Y', '-1', Enter to scale it by a factor of -1 in the Y direction only. Repeat for the 'Y' and 'Z' curves. This will reverse the direction of motion for the empty in each direction.

Select the camera and add a constraint to Track To the empty and the camera should now mimic the motion in the original footage (rather than its inverse).

If you need to adjust the point at which the camera is pointing you can use the F-Curve editor to select one of the curves again and move the entire curve up or down (right-click curve, press 'L' to select the whole curve, 'G' then 'Y') to adjust the position.


My loop cuts are not going around my whole model

The problem is caused by the face that I've selected in the image below (I'm usin a non-default colour theme, so my selections are blue, not orange).

If that ledge really needs to be there, you should give it some volume, but if you're not going to render any views where it's visible, you may just as well delete it, and the loop cut will work.

As it is now, Blender can't tell which direction the cut should go, so it stops before actually reaching that edge.

To delete the face, select it and press X followed by F. Then the loop cut will work as you expect.
If you really need that ledge, select the face and press Y or click Mesh -> Vertices -> Split to separate it from the rest of the mesh. If so, you should also consider solidifying it, CtrlE followed by S or Mesh -> Faces -> Solidify. To set the thickness, enter it in the tool options at the bottom of the tool shelf on the left side. To show the tool shelf if it's not visible, press T or click View -> Tool Shelf.

Now the loop cut will work. However, the ledge will not be cut, since it's no longer connected to the rest of the mesh. You will need to cut it as well, if you need it to be cut at the same places as the archway.


How to delete all faces/geometry that isn't visible? Lowering poly count for unity?

Box selection
Go into edit mode ↹ Tab.
Switch to solid view mode (toggle Z).
Switch to face selection ⎈ Ctrl↹ Tab > F.
Box select the faces. B + drag +  LMB confirm
You have now selected the exterior faces.
Invert the selection. ⎈ CtrlI
You have now selected the interior faces.
Delete the faces ⎈ CtrlX > Faces.


Fluid simulation stays in its own space?

ISSUE - your Effector object uses under Settings > Surface Thickness 10.
It make the distance from liquid.
SOLUTION - reset to default value (with right click) or type zero (or something smaller).

What can be enhanced

Your Domain is very large = wasted divisions for nothing, and long calculation time
Effector topology necessarely complicated = heavier calculation
"Tube" from one container to another container very thin = you will have to increase divisions much higher to get enough details to let flow liquid through this thin part if you imagine grid divisions than will be used in this part.
Inflow is very small = take a lot of time to fill container before liquid starts flow into another container
Cache set only up to 250 frames = it is not enough frames to get result

Recommendations

Create Effector object with clean topology, one sided
Let recalculate Normals Shift+N inside (you can re-check with Face Orientation overlay

Use Solidify modifier if needed to protect from leaking liquid (Solidify has to be before Fluid modifier) or set some low value for Surface Thickness or set some sub-step, but this increase calculation time
Scale Domain as small as possible (just reminder - number of divisions set for domain is represented by small cube in a corner and means how many times is divided the longest edge of domain)

Inflow make bigger or increase Initial Velocity

Before you are not sure about elementary functionality disable Meshing feature that consume computation time as well (to see if liquid goes in right directions, fills what is needed to be filled in given time, and is not leaking in any part ... the coloured particles are more than enough in Replay mode).

What bothers me is cache that should refresh any time some parametr is changed, but that is not happening. What I do is to change divisions about a step back and forth.


Given that the two edges intersect:

Select edge1 and create a new Transform Orientation from the edge's normal orientation.
Select edge2 and snap the cursor to it. ⇧ ShiftS > Cursor to Selected
Subdivide edge1 and select the created vertice. W > S
Set the Pivot center for rotation/scaling to 3D Cursor with ..
Scale the vertice to 0 along its local Y axis. SYY0

Delete edge2 (X) and connect the vertices (F).


Clamp puts a limit to the intensity of light bounced directly and indirectly by surfaces.
It can be used to prevent the annoyoing "fireflies" (random intense pixels in your render) but it is advised to avoid using this feature as it harms the realism of the rendered scene.

It is a good advice to never ever use clamping on direct, and if you're going to use indirect, keep the value rather high (close to the clipping value of the view transform you use) so you don't lose too much energy in your render and bounces and reflections stay realistic.

Using such conservative values for clamping will reduce its efficiency at preventing fireflies, but keep in mind that if you're aiming to photorealism clamping should be your last resort.


Ony the objects that are close appear in the rendered image

You have a scene where things are huge. The room is more than 200 meters long, the TV is larger than a theater screeen, the chair will only be good for giants like the one in your scene...

Then, your camera is set to have a clipping point of 10cm to 100m. Any object that is closer or further away than than the clipping distance will be ignored.

Increase the clipping distance so that it can display objects in the distance.

But as a piece of unwanted advice: in Blender it is better to work in a scale that matches the real world. Physics, and other simulations, depth of field and lighting will behave differently depending on the scale.


You have to go to edit mode, select the two bones, Ctrl+P> Connected.

Also when you have added a bone, and then you go to edit mode. Select the tip of the bones and extrude it with E, then the bones are automatically parented to each other.


The problem is that the collider's normals are inverted.
In solid view with the domain hidden, you can turn on the face orientation overlay to display the front of faces as blue and the back of faces as red.
As you can see, the collider's faces are facing inward:

To fix this problem, select the object enter edit mode, select everything, then press ShftN to recalculate the normals.
After doing this, the collider will work.

For the hallway object, be sure to tick the Is Planar radio button since the mesh is not closed.

To get the simulation fine enough to flow through the cracks, I set the domain resolution to 256.


Draw and update text in viewport without modal operator in blender

You don't need the modal operator to draw things to the viewport. Calling bpy.types.SpaceView3D.draw_handler_add is all you need. Instead of (self, context) you could pass an arbitray object and alter its attributes to modify the drawing. I.e.

class foo:
    def __init__(self, prop):
        self.prop = prop

def draw_text_callback(data):
    #...
    blf.draw(data.prop)

data = foo("Test")

handle = bpy.types.SpaceView3D.draw_handler_add(
           draw_text_callback,
           (data,),
           'WINDOW', 'POST_PIXEL')


sphere acts weird while changing its worldPosition

The answer came from the blenderartist's forum where the user agoose77 wrote

  You need to use

mop.hitPosition

  . The position attribute of the base class of KX_MouseFocusSensor,
  SCA_MouseSensor, returns the pixel position of the mouse, which can
  reach a value in the thousands.

And it worked.


Sorting Collections Alphabetically in the Outliner

Fully recursive and optionally case-sensitive:

import bpy

def sort_collection(collection, case = False):

  if collection.children is None: return

  children = sorted (
    collection.children,
    key = lambda c: c.name if case else c.name.lower()
  )

  for child in children:
    collection.children.unlink(child)
    collection.children.link(child)
    sort_collection(child)

# case_sensitive sort, (default is False)
case_sensitive = True

for scene in bpy.data.scenes:
    sort_collection(scene.collection, case_sensitive)


Control speed of particles on a Curve Guide?

For slower particle speed change the lifetime of the particle to a larger value.

Click on image to see original larger version.

You may also need to make other artistic adjustments.


How can I change the buttons text position?

You can't, Blender's layout engine text alignment (in the internal C code), but Python has no access to this.

This is intentional, Python layout definitions are not supposed to care about details like alignment and color, this is controlled by the layout engine and current theme.

If the layout looks bad this may be a hint we need to improve the layout engine's behavior - its unlikely these details will be exposed to Python, unless theres a very good reason.


Add a cube, scale it to fit your mesh. use Ctrl+A and select "scale" to apply the scale.
Select your complex mesh, add a boolean modifier. in the modifier, select "union" and your cube object.

If everything looks good, apply the modifier.


It seems that the previews module must be explicitly imported to be found:

import bpy.utils.previews

should be placed at the start of the file.


If you keep an edge loop close to the center you can easily do what you want with an Unwrap > Follow Active Quad (you just need to select the whole ring then shift select a last face at the end to make it active). Then unwrap the center and place it wherever you want on your texture.


Apply a texture and a toon shader at the same time

You can use a 'mix RGB' node in this situation and set it to either 'multiply' or 'darken', then tune the mix factor.


I think I've understood what you asked.

What you need then is a mix node for your label/Silver using the backfacing of your label's material. Here is the node setup :

This allows you to use a specific material when your look at the back side of your material.


I am not sure, but i think you clamped the light too much.
I got this:

if i increase your clamping (clamping direct and indirect light) from 0.03 to 0.2


Can't get my model out of wireframe mode

You have the maximum draw type of the mesh set to wire in Object > Display:

This setting limits the drawing of that object to a wireframe, regardless of other settings (it shouldn't have any affect on exporting).

Set it to textured or solid to see the faces.


How do I install Pillow and/or Pip in Blender Python in Windows OS

Okay, I got it to work and in the off chance it might help a fellow (old) person, here's exactly what I had to do.

In the Windows PowerShell I first installed Pip by typing this command in the Python executable directory for Blender:

.\python -m ensurepip --default-pip

Then I downloaded the Pillow wheel file for the version of Python I had (which I found by typing in .\python --version).  I put this file in the same directory as the Python executable (I don't know if I had to do this, but I did anyway).  Then I typed, again, specifically:

.\python -m pip install Pillow

Finally, inside of Blender itself my script did this:

From PIL import image

This worked -- and so I assume now I can use the stuff in the Pillow module (haven't tried that yet, but now I'm a LOT further along and I didn't have to uninstall my Blender Python).


How to render in cycles volume with camera inside

Update

Camera in volume is now natively supported as of 2.73:

  Cycles: Add support for cameras inside volume

  Basically the title says it all, volume stack initialization now is
  aware that camera might be inside of the volume. This gives quite
  noticeable render time regressions in cases camera is in the volume
  (didn't measure them yet) because this requires quite a few of
  ray-casting per camera ray in order to check which objects we're
  inside. Not quite sure if this might be optimized.

  But the good thing is that we can do quite a good job on detecting
  whether camera is outside of any of the volumes and in this case there
  should be no time penalty at all (apart from some extra checks during
  the sync state).

  For now we're only doing rather simple AABB checks between the
  viewplane and volume objects. This could give some false-positives,
  but this should be good starting point.

  Need to mention panoramic cameras here, for them it's only check for
  whether there are volumes in the scene, which would lead to speed
  regressions even if the camera is outside of the volumes. Would need
  to figure out proper check for such cameras.

  There are still quite a few of TODOs in the code, but the patch is
  good enough to start playing around with it checking whether there are
  some obvious mistakes somewhere.

  Currently the feature is only available in the Experimental feature
  sey, need to solve some of the TODOs and look into making things
  faster before considering the feature is ready for the official
  feature set. This would still likely happen in current release cycle.

As user sambler pointed out, fix is on the way.


The problem is some duplicate vertices - 9 to be exact. Go to edit mode, select all, and select Mesh > Merge By Distance. A little window will pop up in the bottom left corner. Click to expand the little box, and press the arrow on the right side once until the value is 0.0101. They will be removed and the bevel will work cleanly.

EDIT - I'm glad the fix worked for you, but after playing with the object some more afterwards, I noticed some anomalies in the topology. Just in case, I have attached a simple .blend file with a similar table in 2 forms - The first has the original topology I used to make the table, and the second one I removed "unnecessary" (for game engines) edges, so it is reduced as far as possible
with the possible exception that I did not delete the bottom faces. Both have the same bevel modifier with the default settings. Maybe use them as a reference or comparison to see what differs between the topology of the 2 of them, and yours.
File is here -
Cheers


What is wrong with my repel player script?

I reworked the whole script from bottom up and came up with the solution that I needed. With this script, any object that triggers the near sensor will be pushed from the origin of the object with the near sensor. The from bge import render and render.drawLine(shieldLoc, objLoc, [0, 0, 255]) is just there to visually see the script when it triggers.

from bge import render
from bge import logic
from mathutils import Vector

def _getForceMagnitude(distance, max_force, max_range):
    return (distance * (-max_force/max_range)) + max_force

def main():
    cont = logic.getCurrentController()
    own = cont.owner
    scene = logic.getCurrentScene()
    #sensor and sensor location
    trigger = cont.sensors["Near"]
    shieldLoc = own.worldPosition

if trigger.positive:
    #iterate through all objects in range
    obj = trigger.hitObjectList
    for objList in obj:
        #location of each object and vecter
        objLoc = objList.worldPosition
        dist = own.getDistanceTo(objLoc)
        vec = objLoc - shieldLoc
        #applying vecter
        vec.magnitude = _getForceMagnitude(dist, 50, 25)
        objList.applyForce(vec)
        render.drawLine(shieldLoc, objLoc, [0, 0, 255])
main()


Objects other than leaves with Sapling addon?

1) When creating the tree with Sapling, choose 'Rectanglular' for the leaves' shape because it will allow you to create a UV map. Also, make sure to select the appropriate leaves distribution.

2) Select your leaves and enter Edit mode.

3) Open an Image/UV Editor window and Activate the "keep UV and Edit mode in sync" option in the UV editor window

4) In the 3D View, select 2 vertices that are on the branch side, they will appear orange in the UV Editor.

5) In UV Window, with the box selection, select all those "branch vertices" which are actually above each other.

7) Subdivide once, you get the vertices that are directly on the branches, select them as well in UV Window and separate with P in the 3D View.

8) A new object is created with only vertices, put a particle system on it with emission per verts. Done :)

Really useful to replace default leaves with nice 3D leaves as well :)

An example. I made the new leaves and fruit using that method (The branches are the default one, ugly but it's not the point) :


Is there any place where I can find .blend files of car interior parts

Blendswap.com contains lots of free Blender models. You can find there some car parts too. E.g. http://www.blendswap.com/blends/tagged/car


Reflection "ghost" when using EEVEE Reflection Plane

Depending on what you consider to be the ghost reflection, you can use one of the following for the glass material:

Both use "backfacing" from the geometry node. To eliminate the ghost, we choose only one reflection (either back or front facing).
On left, the backface is reflective (as front face is transparent).
On right, the backface is transparent (and front is reflective).
0.25 is the alpha value.


How to access an objects DupliGroup instances from Python?

You need to create a dupli-list. eg:

def object_derived_get(ob, scene):
    if ob.dupli_type != 'NONE'
        ob.dupli_list_create(scene)
        ob_matrix_pairs = [(dob.object, dob.matrix.copy()) for dob in ob.dupli_list]
        ob.dupli_list_clear()
    else:
        ob_matrix_pairs = [(ob, ob.matrix_world.copy())]

    return ob_matrix_pairs

# example
import bpy
from bpy import context
for ob, matrix in dupli_list_create(context.object, context.scene):
    print(ob, matrix)

Seealso:

http://www.blender.org/api/blender_python_api_2_74_release/bpy.types.DupliObject.html
http://www.blender.org/api/blender_python_api_2_74_release/bpy.types.Object.html#bpy.types.Object.dupli_list


There is an option called recover auto save, when you go to
File > Recover auto save

You should be able to get a file called something like 9036...or other 4 digit number as in my case. It also migth be called "quit". As long as you have not opened new projects it should be there.

It itself is a file in the temp folder


Blender 2.91 UV Editor. Rip edges keeping them in the same position fails

Indeed it seems like a bug, sorta, I tested and the rip actually works, but once the selection changes, the UV vertices gets joined again (because they are at the exact same place)
tested and worked workaround is to move it a very small amount, like .0001, but not too small so that it doesn't round to zero


Strange mesh deformation when using the action editor?

While you can manually add an armature modifier to an object and set it up to work, the most common method is to start by setting the armature as the parent of the mesh object. While the armature is the parent, moving it in object mode will also move the mesh with it, keeping things aligned.

Once an armature is setup to deform a mesh object moving one of them without the other gives a weird deformation as seen in your screenshot. Even if the armature is the parent you can move the mesh object by itself and get the same bad deformation.

The further apart you move the armature and the mesh the worse the distortion is.

If you have the armature as the parent of the mesh then be sure to move the armature and not the mesh.

If you don't want to use parenting then you need to make sure you move both the armature and the mesh together.

Also scaling one without the other can produce the same result.

That applies to moving the two objects in object mode not moving the armature in pose mode.

One thing to watch is if you use automatic keyframing, you need to make sure you turn it off when you finish animating.


How can I create a single Cycles texture with a different image for each object it's assigned to?

You can use a node group for your settings. The texture is an input to the node group but all other settings are hardcoded into it. Go into the node editor with a material you want to reuse. Select the nodes you want to make common (for instance, hold down shift while selecting). Press Ctrl - G to make them a group. You are now seeing the internals of your group. Press tab to close it. Press tab again to edit it. It is sort of edit mode for node groups. It looks like this:

To the left you see inputs and to the right outputs. There are empty circles on the input and output nodes. Drag from or to these to add more parameters. There is also an editor for this to the right in the properties panel. Here you can add, remove, reorder and rename parameters.

If you tab out you can rename your group.

Now that you have your group. You can use it in other materials. When adding a node in the node editor, your group will show up under groups.

Here I have used my SimpleMaterial on two cubes. One of them got a checkered texture for color and the other got a solid color:


Is there a way to link uv's so as to tile them onto an object?

A convoluted way to do this would be to use the UV Project modifier and 3 empties.

In the center of the cube add an empty.
Add a second empty (empty.001) and rotate it 90 degrees on the X axis.
Add a third empty (empty.002) and rotate it 90 degrees on the Z axis.

Select your UV unwrapped cube and add a UV project modifier, assign the image texture, click the override Imabe box. Change the number of projectors to 3 and assign the empties as projectors.

Then as you modify the cube the textuere will repeat in tiles.


Cycles: how to get glass reflexion on precious stones

Lighting glossy surfaces is always about dealing with whatever is reflected on them.
I think your setup is quite nice, but in my opinion the reflections on the glass could be brighter. I would add more contrast to the surrounding dome's texture.
On the dome you are using for lighting you might want to change the texture to the color input socket and have the intensity be a value you can control:

In this example I'm using a dome with a voronoi texture to create a somehow random pattern for the light. The curves let you control the contrast. The whole idea is to get an interesting a pattern to reflect on the glossy surfaces.


There is a debug tool on linux: "strace"

In blender directory:

strace ./blender-softwaregl --background

or

strace ./blender --background

You can watch the system calls, e.g. the "open" calls too. It will show the path in "open" calls.

example:

user$ strace ./blender-softwaregl --background
..
..
open("/lib/libmvec.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/lib", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
open("/usr/lib/tls/x86_64/libmvec.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/usr/lib/tls/x86_64", 0x7ffe99686660) = -1 ENOENT (No such file or directory)
open("/usr/lib/tls/libmvec.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/usr/lib/tls", 0x7ffe99686660)    = -1 ENOENT (No such file or directory)
open("/usr/lib/x86_64/libmvec.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/usr/lib/x86_64", 0x7ffe99686660) = -1 ENOENT (No such file or directory)
open("/usr/lib/libmvec.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/usr/lib", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
writev(2, [{"./blender", 9}, {": ", 2}, {"error while loading shared libra"..., 36}, {": ", 2}, {"libmvec.so.1", 12}, {": ", 2}, {"cannot open shared object file", 30}, {": ", 2}, {"No such file or directory", 25}, {"\n", 1}], 10./blender: error while loading shared libraries: libmvec.so.1: cannot open shared object file: No such file or directory
) = 121
exit_group(127)                         = ?
+++ exited with 127 +++

-- UPDATE2 --

You can see the paths where "blender" tries to open the libmvec.so.1 file. Pick a path and you could try to add a symlink to the compiled glibc directory.

I don't have a CentOS 7 box, but I have an old Ubuntu machine

-- The whole operation on Ubuntu --

Compile glibc-2.24 on Ubuntu 14.04:

cd ~
wget https://ftp.gnu.org/gnu/libc/glibc-2.24.tar.gz
tar -xvzf ./glibc-2.24.tar.gz
cd glibc-2.24
mkdir _build
cd _build

Your kernel version on CentOs may be different. My kernel version is 3.13. You can get your kernel version by uname -a command on linux.

../configure --enable-kernel=3.13 --prefix=/usr
make

If there is no error on compile, you are done.

Symlinking

Download blender 2.80 beta from https://builder.blender.org/download/ and extract it. Navigate to blender's main folder and:

cd lib
ln -s ~/glibc-2.24/_build/mathvec/libmvec.so ./libmvec.so.1
ln -s ~/glibc-2.24/_build/math/libm.so ./libm.so.6

GO

Navigate to blender's main folder.

headless version:

./blender-softwaregl --background --python-console

gui version:

./blender

It works for me on Ubuntu 14.04


This appears to be due to a several things:

Transparent is enabled in Render settings > Film.
This renders the image with alpha transparency instead of sky. Useful for compositing, but hides the sky texture (at least in viewport render).
Ray visibilities are disabled on the world material.
The compositing setup doesn't take into account the sky texture. This is understandable, as a real-life camera would over-expose the sky when taking a picture with a reasonably exposed interior.

So to make this work, you'll need to modify the compositing setup.

Start by adding your sky texture to the world material. Ensure the strength is set correctly and at least Camera ray visibility is enabled:

Disabling Properties > Render > Film > Transparent won't work in this particular case, since the compositing setup uses it create glare from the sky. Instead you can use the Environment pass:

Enable the environment pass in Properties > Renderlayers > Passes:

Connect the environment pass output of the _mainScene Render layers node to the Alpha over node in the COLOR CORRECTION frame:

You may have to reduce the amount of glare by reducing the Fac value of this mix node:

Render:


If you're talking about exporting, you'll have to press the "animation" button.


How to scale a light's size , and strength proportionally with the rest of the scene in Cycles?

You need to scale the light intensity according to the inverse square law. [Calculator]

When dividing scene size by 6, divide light power by 36.
When dividing scene size by 10, divide light power by 100

Important note:
Point and Spot lights don't change their Size when scaled with the scene. You need to change their Size manually in the Lights panel. Area lights scale properly with the rest of the scene.

Example:
Scene scale divided by 6. Point light Size also divided by 6. Point light power divided by 36.


You should duplicate a single edge loop around the ankle, and then extrude, move, scale and rotate it until you have the entire foot covered. Because of the geometry of feet, it's more efficient to take the time and model the sock, rather than try and base it off the geometry of the foot.


First, if possible, create a "minimum unit" of your pattern. For example, given these 8 shapes:

you can join them together (select, CtrlJ), but then you also have to put the pieces that "leak" into the next unit square back into the repeating unit:

The complexity of this task really depends on your model!
Make sure your pattern is "laid flat" onto the X-Y surface: rotate it in the right way, then CtrlA > "Rotation & Scale"

Enable the "Tissue" add-on:

  File > User Preferences > Add-ons > "Mesh: Tissue" > check

Create a cube, set the subdivision surface modifier, set the render divisions to 1, then "Apply".

Select the pattern, then Shift+select the subdivided cube, hit Space and search "Tessellate". Choose XY: adaptive, Z: proportional, and hit "ok". You may want to enable "smooth" shading on the resulting mesh.

This will create a patterned mesh, made by repeating your patter on every face of the subdivided cube. It works because the object is made of quadrilateral faces. it wouldn't work on a UV sphere or Icosphere.


Why aren't move parameters staying with my object?

The option menu two boxes to the right of where it says Object Mode, is the Pivot Point, you have it set to 3D Cursor. Change it to Median. I think that is what you are asking, but you may need to be more clear. :)


Active dynamic rigid body object does not move since linked to armature

FINALLY FOUND OUT THE SOLUTION:
i have checked and tested anything, and saw that nothing, old or new, linked or not, objects, will not animate after frame 250. i could see the cache like down the timeline that stops after this frame.
according to this page ( https://docs.blender.org/manual/en/latest/physics/rigid_body/world.html ), i have increased the Scene Properties/Rigid Body World/Cache/end from default 250 to the desired, in my case 1286, and started the whole animation from frame 0. and it cached all with the line below timeline and at last this was the result:

Here it is:


Just move your mirror modifier before your boolean modifier like this:

Then it works:

UPDATE:
ok, then just add a mirror modifier for your cut object (cylinder) too like this:

result:

blend file:


Cycles, material with color based on height and backside in different colors

A basic way to control the color based on height would be to use the coordinates on the Z axis and have those control a color ramp.

To have the backside be a different color use bacfacing, from the geometry node, to control the mix with a different shader.

From there on, is just a matter of making the material as complex as you want until you are happy with the results.

or

Endless fun playing with textures.


How to Add a Material to a Lamp in the Blender Game Engine

If you're still trying to do this, or if someone else is trying to, you can animate the brightness of the spotlight and use logic bricks (or python) to play that animation.


How to speed up blender animation playback. It is slow

Actually your GPU will have a little impact on your view-port fps when playing animation. If you are able to rotate/navigate without lag, your GPU can handle the geometry fine (almost any modern GPU will handle millions of polys). Then if you get slow fps in playback the bottleneck is somewhere else.

If you get lag in just navigating view port check the OpenGL settings in User Preferences under System tab. Enable VBO.

Between each frame, the scene has to be updated with all the objects inside - this happens on CPU. Behind the scene this is managed by Dependency graph - a structure that keeps track what is dependent on what (parenting, constraints, ..). The current dependency graph is obsolete and is single threaded in many places = does not use all the CPU power, has poor optimization = is re-evaluated in cases where it is not needed, etc.

You can try the new DepsGraph with a command line argument (see the link above).

Things to do to help your animation fps (if anyone has other tricks or I forgot some feel free to expand the list):

If there are simulations/particles always bake or at least cache them so they don't need to be recalculated between frames.
If there are deformations on subdivided geometry use Simplify in Scene properties to limit the subdivisions - less vertices have to be updated. Or try the OpenSubdiv option to calculate it on GPU (but this still has limitations)
Close any other view-port windows - have just one. Set it to Only Render in the Display settings in Properties panel (N). If you have animated textures close also Image/UV windows.
If your deformed geometry doesn't change vertex order/count you can export it as .mdd file format and import back in Blender or bake it into Shape Keys.
There is not much else you can do, if nothing works the scene is just too complex and your only option is to preview the animation with OpenGL preview render (button in view-port header)


Why is this image not staying in place when using the UV Project modifier?

Here is a setting with 3 empties as projectors on a cube.

Face: pointing to the cube's face. Z of the empty is opposite to the face
Right: pointing to the cube's right par. Z of the empty is going right (opposite again)
Left: same principle

Use "override image" option in the modifier.

Each empty has been moved and scaled to fit the image texture at the wanted location.

edit as unclear. If you don't use override option, just make so the empty are well oriented (minus Z pointing to the wanted face). It supposes that you have placed the UV map correctly before using the modifier.

Related documentation


Yes, Blender 2.78 and above versions all have support for Pascal architecture (10 series)


Absolute path of files in Blender (with Python)

The // prefix is Blender specific to denote relative paths used within Blender,

To use Python's filesystem functions you'll have to first expand this using:

bpy.path.abspath, to replace os.path.abspath
bpy.path.relpath, to replace os.path.relpath

eg:

filepath_full = bpy.path.abspath(image.filepath, library=image.library)

Unlike ./, which simply expands the current-working-directory (os.getcwd()), Blender supports library-linked files. This means the directory of the current data-block could be a different path then the currently open Blend file.

If you are operating data which the script created, You can skip passing the library argument.

filepath_full = bpy.path.abspath(image.filepath)

Note that this isn't specific to images, it works for movie-clip, sounds, sequencer and text blocks too.


I have doubles, and remove doubles won't delete them

Looks like you don't have duplicate vertexes. Looks like you have an edge on the inner vertexes and another edge from the farthest vertexes. The edges overlap where you circled.
You can try to delete the edges and create them correctly, then recreate the needed faces.


Got it to work with Bmesh (not necessary but easier to work with IMHO).
Had to add several chunks of code that will generate 4 waves as the main longitudinal edge loops, and add faces to the mesh.

This can be fairly easily expanded to generate other shapes, or non-quad based struts. Here you can control the width (thickness) of the 3D strut via the width global and zw / xw variables within the loop.

I also changed the strut function a tiny bit. Instead of normalizing between -4 to +4 X pi, I just use the Y values provided. In this example I'm providing the minimum and maximum Y values as multiples of pi directly, so I removed the normalization to open up the possibility to create a wave in whichever length and number of peaks you want.

Here's the code:

import bpy, bmesh, math
from mathutils import Vector
import numpy as np

numPoints  = 100
yMin       = -3 * np.pi
yMax       = 1 * np.pi
width      = 0.5

def strut( x, node_dist = 5, amp = 1 ):
    """ Takes 1D array x, creates shape y values """
    return amp / 2 * np.cos(x) + amp / 2  # adjusting position and amplitude

bm    = bmesh.new() # Generate bmesh object
loops = []          # Strut major longitudinal loops array

# Calculate vertex coordinates
# Essentially generate 4 longitudinal loops that represent the top, bottom. left and right edge loops of the strut
y = np.linspace( yMin, yMax, numPoints )
for zw, xw in zip( [1, 0, -1, 0], [0, -1, 0, 1] ):
    z = strut( y, amp = 2 ) + zw * width
    x = strut( y, amp = 0 ) + xw * width

    loop = [
        bm.verts.new( Vector(( xi, yi, zi )) )
        for xi, yi, zi in zip( x, y, z )
    ]

    loops.append( loop )

# Add faces
for i in range( len( loops ) ):
    for j in range( len( loops[i] ) - 1 ):
        verts = []
        if i == len( loops ) - 1:
            verts.append( loops[0][j] )
            verts.append( loops[0][j+1] )
            verts.append( loops[i][j + 1] )
            verts.append( loops[i][j] )
        else:
            verts.append( loops[i][j] )
            verts.append( loops[i][j + 1] )
            verts.append( loops[i+1][j+1] )
            verts.append( loops[i+1][j] )

        bm.faces.new(verts)

# Add caps faces
for i in [0, len( loops[0] ) - 1 ]:
    bm.faces.new([ loops[j][i] for j in range(len(loops)) ])

# Generate mesh data and object, and link to scene
m = bpy.data.meshes.new('strut')
bm.to_mesh(m)

o = bpy.data.objects.new('strut', m)
bpy.context.scene.objects.link( o )


How to insert keyframe only "Available" in blender 2.78?

The available function is still there.
It does require a pre-existing keying set to add keyframes to.

In this example there are no keyframes (therefore no keying sets)

Once I add a keyframe for location, then you can add more keyframes to that set with available.


How do you make a sharp angle with Bezier cruve?

Pressing V will give you a menu to change the handle type, choose "Free". Then you can move the handles fpr the control points independently.


Solved! For the sake of better organization, I had my high-poly meshes in a separate collection from my low-poly meshes.

In the Outliner window, I dragged the high-poly mesh into the same collection as the low-poly mesh, and after that the normal map baked properly (not perfectly, but it's at least a starting point.)

So I think what I'm missing is an understanding of what Collections are in Blender and how they are used; I was assuming they were a way to organize and collectively edit groups of objects in a scene (basically what it says on the tin), but evidently there's more to it than that.

(Haven't looked into details of why this worked yet, but it just bugs me when an op comes back with "solved!" but gives no explanation of how they solved it, so this is what I've got.)


How to render a video based on "material preview" viewport shading

You can render animation from viewport, by choosing View -> Viewport Render Animation
[
You may want to disable overlays (icon is located in top right by default), or disable specific parts of it in the drop-down menu.


how to use a driver to drive object on object's local axis

AFAIK, you have two options:

Assign a Transform constraint to the object. This allows you to map a transform range of the source object to a transform range of the target object, in either their World or Local spaces.
More conventionally, parent the driven object to another one (often an Empty). Then the driven object's transform will be evaluated in its parent's space, in a driver expression. If the parent is aligned to the child when the relation is formed, that will be equivalent to the child's Local Space


Why isn't local transform orientation doing anything?

It looks like you have applied transformations using CTRL+A.
If so, you can try enter Edit mode and select Transformation Orientation to Normal.

Another option is using for example a model's edge and move the model's geometry by it's normals, then reset the origin - like this:


Why is the middle dot of the face outside the face itself?

The ‘dot’ representing the face is positioned at the “centre” of all the vertices of that face - calculated as the average over all vertices. In your case you have a large ngon with many more than 4 vertices and the ‘average’ happens to be outside your mesh (drawn away due to all the vertices along the curve).

It isn’t a problem that the ‘centre’ of the face is outside the face itself but it might be a problem that the face is an ngon (more than 4 vertices) as it can cause problems further down the line (eg, when trying to animate or subdivide the mesh). It would be best to delete the face (X, Faces Only) and re-create it with better geometry (quads/tris).


Rather than keyframe with Constant interpolation, you can simply keyframe normally (using smooth interpolation) and add a modifier to your f-curves to mimic the 'jumpiness' of stop-motion.

The modifier you need to use is the Stepped Interpolation modifier. This modifier takes your f-curve and splits it into time slices based on the Step Size, retaining the value at the start of that 'slice' for the duration of that 'slice' exactly as how you are currently doing with 'constant' interpolation.

You will need to add the modifier to each f-curve in the Graph Editor and set the Step Size to the same value for each.

Note : For added versatility you could potentially use a Driver to set the Step Size based on a single custom property in your scene. This way you can easily adjust the stop-motion frame rate for your whole animation rather than having to change each modifier individually.


There is nothing wrong. Also consider switching to EEVEE or Cycles with a denoiser like Intel Open Image Denoiser, Optix Denoiser or internal one.

This you can get by tweaking some values:

Materiel view

Render


How do I change the default data settings for an empty?

There's no mechanism to change the default, or setting in preferences. It could be added but frankly it's not likely to be considered worth the effort.

When creating the Empty it is picked from a dropdown menu, the next menu item down is Arrows. Moving a few pixels down with the mouse is probably the most non-invasive solution.

Existing key-combos

But by far the easiest is the shortcut sequence Shift + A  >  E  >  A

Making an add-on

But you could write an add-on / operator and bind it to a shortcut to make Arrows the default display type for Empties generated by the operator. See this post for most of the code you'd need.

Add Shortcut

You can also make a shortcut, by right-clicking on the Arrows menu item and choosing Add Shortcut, and it will ask you to press a key or combo.


Why is it important to align bones to view axis?

The operation is "recalculate roll."  It can be accessed from the armature menu, via armature-> bone roll-> recalculate roll-> whatever.
You don't necessarily have to align bones to the view axis specifically.  What you want to do, though, is make sure your bones have appropriate tilts.  Using the recalculate roll option to do so is the easiest way to control your tilt.  (I tend to recalculate to cursor myself.)
Why?  Think about a lower arm bone.  Your elbow rotates in a single axis, more or less, and if you animate a model where its lower arm rotates outside of this axis, it's going to look broken.  So you're either going to use angle limits, or transform locks, or IK angle limits, or expect the animator to animate in specific bone-local axes.  Doing any of these requires that you set the tilt such that the unlocked axis corresponds to the way you actually want the elbow to bend.
In the case of Euler transforms, this is even more important.  An XYZ Euler interpolates well with X rotation, but once you start combining it with Y and Z rotation, you can get some funky, counterintuitive interpolation.  So an Euler bone should be set such that its X axis rotation corresponds with the most likely, most extreme rotation with which it's going to be animated.


I was able to bake three objects on one UV Map texture by doing the following:

In UV Image Editor, create a new image texture. I did a simple black 1024x1024.
Select all three objects. Tab into Edit Mode. Unwrap "Light Map Pack" for quick and dirty testing. You will see the unwrap of all three objects evenly distributed across the UV image.
Create materials for your objects.
Add a "Image Texture" node to each object material (but do not connect it to anything). Make sure the Image Texture node has the UV map you created for baking in it. You should see "3" users for that Image Texture node. Make sure that node is selected / highlighted in each object.
Select your objects and hit bake.


How to make objects follow armature bone shape? (images included)

Looks like you have weighting wrong: delete the armature modifier you have created, select the paper, then the armature, then Ctrl P and choose "with EMPTY GROUPS option".
This option will create 3 empty vertex group with the same name of the three bones,  that can be manually weighted:
select the paper and enter in edit mode
select the vertex group tab in the properties window, select the first bone, select all the vertices around the first portion of the plane and click assign.
Do the same with the others two bones/portions of plane.

Done.


Object Duplicated when exported into FBX

The mistake wasn't in the export setting but the meshes. It had hidden meshes that was I believed that it got duplicated. It can be solved by two approaches.
1:  Deleting the hidden objects
2:  Export by checking selected objects

Thank you guys who tried to help.


For still images, this is fairly easy, cloth simulation is a modifier, and like any modifier it can be applied. This will apply the simulated shape at the current frame to the mesh, thus allowing you to then change the frame to the one with your preferred smoke simulation state.

If you want to make it look like the cloth is being blown by the smoke, you might want to look into a wind force field.


Nvm, the toggle x-ray option was toggled on and you need to toggle that option off before going to weight painting.


Where can I find the rig layer menu in blender 2.9

It's still there.
Make sure you have "rigify" Add-on ON, add the meta-rig (Add > Armature) and then you need to generate the rig. For more info about rigify here


Changes have been made to improve the way snapping works.
You can now choose which type of snap affects transformations.

In the snap popover towards the bottom activate Scale to use vertex snapping while scaling objects.


Strange size when creating a cube using bpy.ops.mesh.primitive_cube_add

My suggestion is don't use it.
Can see reason for confusion, have personally never used the scale value in the operator, (fortunately because yeah it's bloody confusing) Speculate there could be some legacy nature about it.
Crunch any operator into the python console   auto complete Tab  will show defaults of an operator
>>> bpy.ops.mesh.pri<Tab>mitive_cu<Tab>be_add(
primitive_cube_add()
bpy.ops.mesh.primitive_cube_add(
        size=2,
        calc_uvs=True,
        enter_editmode=False,
        align='WORLD',
        location=(0, 0, 0),
        rotation=(0, 0, 0),
        scale=(0, 0, 0))

Construct a cube mesh

There is no need to pass any default to an operator.
One would suggest the default for scale should really be (1, 1, 1), notice too how scale is not used in the operators panel

Let's run some tests to see what we get for different size scale combos...
import bpy

tests = (
    (0, (1, 1, 1)),
    (1, (0, 0, 0)),
    (1, (1, 1, 1)),
    (1, (2, 2, 2)),
    (2, (1, 1, 1)),
    (2, (2, 2, 2)),
    (1, (1, 1, 4)),
    (2, (1, 1, 4)),
    (2, (2, 2, 8)),
    )

x = 0
for i, (size, scale) in enumerate(tests):
    # Create the default cube
    bpy.ops.mesh.primitive_cube_add(
        size=size,
        scale=scale,
        location = (x, 0, 0),
        )
    cube = bpy.context.object
    cube.name = f"Test{i}_{size}_{scale}"
    print(size, scale, cube.dimensions[:])
    x += cube.dimensions.x

and OMG or WTF the Results.
0 (1, 1, 1) (1.0, 1.0, 1.0)
1 (0, 0, 0) (0.0, 0.0, 0.0)
1 (1, 1, 1) (1.0, 1.0, 1.0)
1 (2, 2, 2) (1.0, 1.0, 1.0)
2 (1, 1, 1) (2.0, 2.0, 2.0)
2 (2, 2, 2) (2.0, 2.0, 2.0)
1 (1, 1, 4) (0.5, 0.5, 2.0)
2 (1, 1, 4) (1.0, 1.0, 4.0)
2 (2, 2, 8) (2.0, 2.0, 8.0)

size 0 has dimensions, scale 0 doesn't ... same results for.. are you still confused?
In the end comes down to don't use it.
Matrices
Onto the soapbox and suggest the use of matrices. If we wish to apply a scale of (1, 1, 4) to the default cube of known dimension (2, 2, 2) can
from mathutils import Matrix
S = Matrix.Diagonal((1, 1, 4)).to_4x4()
cube.data.transform(S)
cube.data.update() # see result in viewport.

or equivalently can create matrix via
S = Matrix.Diagonal((1, 1, 4, 1))
Sz = Matrix.Scale(4, 4, 'Z')
Sz = Matrix.Scale(4, 4, (0, 0, 1))

Matrices can also be used when creating bmesh primitives as demonstrated in How to create cylinder with varying radius at different height


What does the mapping type do on a mapping node?

The mapping node works by changing the coordinate system. This is why (when left on the default point setting) you have to put in a larger number to scale a image down. What is you are actually doing is scaling the texture coordinates up.

When set to Texture you are still changing the Coordinate system, not the texture. The only difference between Point and Texture is that for texture all the values are inverted.

Try it, when set to point a value of 2 is required to make the texture repeat 4 times.
When set to texture to get the same repeating 4 times the value must be .5.

I would highly recommend going through the cg cookie tutorial (archive) about the mapping node.


Blender supports the STL (STereoLithography) format which is supported by all printers and considered as standard for prototyping.

Shapeways for example supports the file types: STL, OBJ, X3D, Collada or VRML97/2.

Blender comes with support of STL, OBJ, X3D and Collada.

Documentation on import formats
Documentation on export formats

When there is a public demand for a specific file format someone will create an import / export addon for it.


Why does my sculpting not working like how it does on this video

Maybe you need to subdivide the mesh further to increase detail.

Try subdividing once more to increase the number of faces for the brush to work on.


Tranparent object is hidden behind tranparent object

Global collapse of hidden faces is enabled. Just disable it and solve the problem.


Add bezier curve to vertices along a plane?

You can apply a bezier curve to a plane using the knife project tool.

Heres my process:

As a separate object, make the curve that you want (mine is pretty bad for a door):

Next, covert the curve to a mesh using the "convert to" tool:

Now, select first the curve mesh, and then the plane, go into edit mode, and do knife project:

The knife project does it from your view, so you want to use align view to make sure you are looking at the plane head-on.

Now, you will have the curve cut into your plane:


Full sphere (or double hemi sphere) lighting

Cycles has no support for hemi lights.

But you can do this with no lights at all, the same way you would do it if you were lighting using an HDR image.

Just make the world white and your object will be lit from a sphere that surrounds the scene.

It will give you flat even lighting from all directions.


Clean sphere separation with a sphere created from a cube

As Martin Z says, you don't say enough about your problem, also, what problem did you meet with the knife? To cut with the knife, press K for activate, then Z to cut through, then C to cut orthogonally

But if we keep your request, it looks like if you select an edge loop (alt right click), then scale it to 0 on the Z axis with S Z 0, then W > LoopTools > Circle, it works fine. Don't forget to activate the LoopTools addon in the Preferences.

And to separate a mesh in two parts, select the edge loop and press V.


Height Map to Mesh conversion considering Transparency

The issue here isn't that it's not ignoring black.  It is.  (Technically, it's treating it as 0 displacement.)  The issue is that the areas that look black to you aren't fully black.  Open your image in something like GIMP and click around.  You're going to see that some of these pixels that you thought were 0/255 are actually up to 5/255.

If you're doing displacement in nodes, you could do some math editing there, but based on your goal, I bet it's via modifier.  You can do a little bit of editing of textures to bury the not-quite-black in Blender by adjusting brightness and contrast, but it screws with your picture in ways you might not like.

Really, the right place to do this is in an image editing app.

Displacement modifier is already reading your alpha as 0 displacement (black), despite the fact that the color underneath the alpha is white.  The reason for the border around the alpha, again, is that the rest of it isn't actually fully black.

I would recommend using higher color depth for displacement maps, especially those used at this scale.  Try making your image in Blender as a 32 bit, and if this kind of image is all you need, you should be able to paint it directly in the UV editor by switching from View mode to Paint mode.


Blender merge vertex to edge and remove additional edge

It looks like you should create 3 loop cuts (CTRL + R), as marked by green lines, in order to fix your topology and make it easy to connect A with B.


Get parent from a collection that's already in a collection

Maybe for objects in door.children since you're parenting them?

Yeah it could be cool to use magic method looping over children


A sun lamp with size 0 will give you a very sharp shadow:

As you increase the lamp's size it will give you much softer shadows.

related: Meaning of Sun Lamp Size?


I have since found the cause - User error.

Blender was running fine but as I was scaling from a 4K to HD image it was processing the 4K image, then scaling then processing the HD image, which took 6 times longer. I exported a HD version of the images and used that and render times dropped to .7s/frame, which is what I was expecting.


Why can't I parent objects in my .blend?

Set outliner display mode to Scene

I wonder if this is the outliner display mode being viewlayer rather than scene as default. Was a source of confusion for me the other day as  parent relationship works, but in viewlayer display doesn't show as hierarchy like we are used to in 2.79 and prior.

In your file cube is a child of another cube that is a child of the empty. Can drag around in outliner after setting display mode to scene and parenting works as in previous versions with drag and drop.


How to create realistic lighting at night in Blender Cycles

First of all, I noticed that your image has a pretty light-blank sky. (by which I mean that there really isn't light coming from it.) Light always comes from the sky, even at night. You can see the difference in the image you provided as a target.
You need a HDRI (high dynamic range image). these can be found quite simply by Googling HDRI maps. You can also render your own from blender, but that's a different story. If you want to use your existing sky, it'll work, but it may look weird. Change the color setting of your sky to environment.
I would also add an emission node to some of the windows. if you increase the amount of your fog glow node this'll give nice results.

Now obviously you don't want a model that took four minutes to make, but you get the gist of it. What really makes the example picture you have nice is that there are reflections off of the interior walls. This can be accomplished with a glass shader and some lights inside the building. Note that it will look better close up, worse far away, and better overall if you use a texture on the building. I used brick.


How to add extra loop cuts without affecting subsurf

You need to add some geometry to your mesh. Then add some edge loops around with some bevels and ctrlR, delete faces, extrude, move a bit the edge loops you've created to make the hole round, and extrude inwards. To make the button just duplicate the hole profile and extrude.


Solved in comments:

A shadow needs to hit something, in order to be seen. Add a plane or another object where you expect the shadow to be seen.


Try looking in the outliner to see if something that is hidden(the eye is grayed out) is set to render(the camera icon is NOT grayed out).  If you want to hide this object you can click the camera and it will not render in the final render.


How to get the updated rotation of an object during soft body physics simulation?

Issue with all vert coords in vg summing to zero.
Made a quick demo to have a squiz,
Using 2.91 ran into this issue
Default Cube set up to drop on plane using physics. An all vertex group "Group" is added, and two constraints, as demonstrated with code above.
All constraints use default values unless otherwise stated.
Obvservations:
For copy rotation constraint.
Using no subtarget --> Empty same rotation as cube.
When using all vert vg "Group" as a subtarget  --> Resulted in Identity (zero) rotation.
Using a group with only 3 vertices --> Empty rotates, but is aligned to normal of 3 verts plane.
Editing the cube by moving one corner such that it is no longer symmetrical also sees rotation when all verts used as subtarget.
Similarly if both constraints are replaced with one copy transform constraint, in which case "Group"  makes the empty disappear (scale to zero). Despite there being only unit scale on all objects involved
Didn't try but the other similar constraint would be parent to.
Conclusion.
Either don't use a subtarget, or make sure the sum of all vert coords  in  subtarget group do not sum to zero,  for constraints that involve rotation.
Really  only need the subtarget if also deforming the mesh.
Perhaps someone can elaborate whether this behaviour re using all verts vg as a subgroup not rotating is by design, or a bug of sorts, when caused by the sum of all cube verts being zero a zero vector...
With one of the working options selected, used script below to add an empty at each tenth frame with same matrix world as constrained empty.
import bpy
scene = bpy.context.scene
fs, fe = scene.frame_start, scene.frame_end
tg = bpy.data.objects["Empty"]

for frame in range(fs, fe):
   scene.frame_set(frame)
   print(frame, tg.matrix_world.to_euler('XYZ')) # This gives me completely random rotation vectors
   if not frame % 10:
       bpy.ops.object.empty_add()
       mt = bpy.context.object
       mt.matrix_world = tg.matrix_world
       mt.name = f"frame_{frame}"
       mt.show_name = True

With the physics baked, ran it and the added empties align with the constrained empty at their respective frame.
PS can make an all vert group with
group.add(range(len(mesh.vertices)), 1.0, "ADD")


Blender 2.80 requires macOS 10.12 or later, your operating system is not supported. You can still use Blender 2.79 and earlier versions, all new versions will require an operating system upgrade.


Is it possible to get blender to find the missing blender files like
  it finds missing image files so that i can preserve the previously
  made animation?

Yes, totally. Go to "File > External Data > Find missing files".
You can navigate to specific folders if you know where you put your files. as blender searches sub-directories you can even say: "Hey blender, my file is somewhere in here, just look for yourself" on your documents folder.

  On a side note is there a way to also view a list of all the missing
  files?

Yes. There is.
"File > External Data > Report missing files" prints all missing files to the console (in the default layout you can all down the menu on the top to see the console's content.)


How to make grease pencil draws permanent?

I figured it out, you have to go to the right menue and press on the button Frame locked


I'm having flickering problems with meshes in blender2.83 especially in edit mode

This problem is caused by an anti-aliasing bug. You can disable anti-aliasing in "Preferences > Viewport > Quality", or wait for the next release.


You need to parse the string to work out how to calculate the offset to use.

If you say that one blender unit equals one metre then :

offset = '99cm'

if offset[-2:] == 'cm':
    true_offset = float(offset[:-2]) * 0.01
elif offset[-2:] == 'mm':
    true_offset = float(offset[:-2]) * 0.001
elif offset[-1:] == 'm':
    true_offset = float(offset[:-1])

offset[-2:] extracts the last two characters, while [:-2] gets everything execpt the last two, which is the number. A more complete solution would scan the string for characters and digits to extract the two parts.

Depending on where the measurement data is coming from, you may also need to account for thousand seperators and spaces.

If you want to support imperial measurements then you will also want to take into account imperial suffixes and possibly do imperial to metric conversions.

You may also want to take into account the scenes unit settings. You can get these settings from the scene

scn = bpy.context.scene

scn_system = scn.unit_settings.system # NONE METRIC or IMPERIAL
scn_scale = scn.unit_settings.scale_length
true_offset = true_offset * scn_scale


How to get the base dimensions of an object (ignoring all of it's modifiers)?

Look at the mesh coordinates.
The unmodified dimensions of the mesh can be obtained from the mesh.
import bpy
import numpy as np

ob = bpy.context.object
me = ob.data

coords = np.empty(3 * len(me.vertices))
me.vertices.foreach_get("co", coords)
x, y, z = coords.reshape((-1, 3)).T

mesh_dim = (
        x.max() - x.min(),
        y.max() - y.min(),
        z.max() - z.min()
        )

print(mesh_dim)

Could use this to give a mesh a dimensions property
import bpy
import numpy as np
from bpy.props import FloatVectorProperty

def get_mesh_dims(self):
    coords = np.empty(3 * len(me.vertices))
    me.vertices.foreach_get("co", coords)

    x, y, z = coords.reshape((-1, 3)).T

    return (
            x.max() - x.min(),
            y.max() - y.min(),
            z.max() - z.min()
            )

bpy.types.Mesh.dimensions = FloatVectorProperty(
        name="Mesh Dimensions",
        get=get_mesh_dims,
        subtype='XYZ',
        unit='LENGTH',
        )

python console code, default cube, arrayed subsurfed spun and hung.
>>> C.object.data.dimensions
Vector((2.0, 2.0, 2.0))


Use OpenEXR multilayer.

Think of EXR as a perfect copy of the render layers. Multilayer will allow you to save all of the different passes.

EXR will keep your information linear and un-distorted by color transforms, with the proper associated alpha channel and the z pass as unbound data.

Enable the render passes that you want in the view layer.

Use a File Output node, create as many layers as you need with the Add input button. Then plug the output sockets of each of the render layers you want to save.

Png is a terrible format, never meant for compositing.


Giving the wall thickness of hollow irregular pipe. Solidify not working well with the problem

I don't think the solidify modifier was meant to handle such complex geometry. If you apply the modifier, you can repair any irregularities by hand.

The other idea would be to use the Shrinkwrap Modifier. It's ability to take the closest surface point as reference makes it pretty invulnerable to small holes.

Below is the result of a Cylinder with just 8 sides. I sandwiched the Shrinkwrap Modifier between two subsurfs. The first one decides how many verts the shrinker gets and the second is for smoothing. That way you can tweak how much inner surface structure leaks through.

All that's left is to apply the modifiers, join the meshes and stitch them together.


VSE is neither previewing nor rendering multilayer EXR sequences

According to this thread directly exporting an exr-sequence in the VSE is not possible, as in it wasnt designed to do that.

Either export your exr sequence to some other format using the compositor, OR just plug what you want of the exr into the composite node and then get that data into the VSE using a scene strip.


can I use ocean modifier on any custom shape?

Yes.
Set the ocean modifier to displace instead of generate:

Note that your mesh must be pretty highly subdivided for it to work well.


Why my spot lights do not work properly?

From your screenshot, your lamp is only rated as outputting 1 Watt of power. You are effectively trying to illuminate your scene with around 6 Watts of power - 1/10th of a 60W lightbulb, presumably at many metres (Blender Units) range - so your scene is almost completely dark.
You need to simply increase the output of those lamps to more reasonable levels - eg, 600 Watts per lamp would be more reasonable.
I suspect you have gotten into this situation by duplicating the original Sun lamp and changing its type to 'Spot' without changing its output. Note that Sun lamps are rated in 'Strength' - with a strength of '1' equating to 1 'Sun' (our sun) - but Spot lamps are rated in 'Power' (in Watts). When you change the lamp type the Strength gets changed to Power but the value remains the same (so 1 'Sun' gets changed into a 1W lamp). When changing between types, always check the other settings to ensure they are still reasonable for your situation.
In summary, increase the output from your lamps.


How to save print-quality screenshots of the 3D view?

Have you considered the OpenGL render? You can set the resolution in the render tab, then just click the render button in the toolbar at the bottom of the 3D viewport.:

It then renders an image of the viewport (without the grid) that you can save. It also works with animation.

The render anti-aliasing settings are used so for a higher quality result you can set it to 16, since its OpenGL the additional samples are typically still quite fast to render and help to give a smoother final image.

Here's a 4K render done with the OpenGL render:


Help implementing Script node for material

The related post you mentioned is not in Python but in OSL. In order to enable OSL you must set your render device in CPU mode and enable the Open Shading Language Option. I tried the code and it was working quite good (except the last part which crashed my machine).


How to bake Mantaflow simulation in version 2.83

You need to switch to Settings > Cache > Type > Modular:


Maybe the hardsurface nerds will refute but I don't think you can. So I guess the solution is to select your vertex and to bevel it with a shiftctrlB.


How do I make the mesh more jagged in sculpt mode?

I haven't used sculpt mode much but I would imagine you might be able to do it using a flatten brush if you turn up the strength but set it to a really small radius. If it doesn't work I apologize for wasting your time.


Custom Area bl_space_type not possible without building Source exe?

Currently this is not possible and also no plans are yet revealed by any developer to make this possible from the python API only.

Making this part fully in python and supported by the community will not be an easy task. Are you up for it?


With Python, how to access a vertex group created by parenting to an armature with auto weights?

The vertex groups are on the mesh object, not on the armature. The armature itself doesn't have any vertices.

>>> list(vg.name for vg in D.objects["Cube"].vertex_groups)
['Bone', 'Bone.001']


Pitchipoy is very sensitive - meaning you can't change anything except the position of the bones. You cannot change names and you certainly can't change bones. If you add a new Pitchipoy rig and enter edit mode you will see it has 159 bones. Your rig has 157 meaning you delete 2 bones and hence broke the rig.

Updated: Not completely true that you can't add bones - that is possible in Edit mode > Rigify Buttons > Add Samples. Helpful information is also in this answer on changing the finger controls.


Blender 2d animation, Draw lines in draw mode but cannot erase them, cannot edit them

I just realised that in Blender 2d animation. locking a material from being edited also lockes any strokes from being selected and moved if they have this material.
This is really confusing Grease pencil feature, it made me asume I had the layer locked even though it seemed like it was unlocked, or I had the stroke on the wrong layer. Spent the last 2 hours troubleshooting it and trying to recreate it.
It means you can draw lines in draw mode but cannot erase them, cannot edit them.
Locking materials seems like it should just stop the material from being edited but it locks what it has been applied to as well.
Anyway just posting as I spent so long googling and could not find the solution. was about to admit defeat and delete my project and start again, assuming it was strange bug. hopefully a google search with bring this up for the next person who gets this issue


Would 1 million faces/vertices be too much for Blender?

1 000 000 faces shouldn't be a problem.
High facecount by itself won't slow down renders very much, this isn't the 90s.
Viewport is slowed down by high memory - face count, high-res textures and complex shaders
Render is slowed down by high light-bounces, HDRIs, and complex shaders (glass, SSS)
To keep memory low (and viewport fast):

link objects, don't append them when building a scene
use lower Subdivision levels for Viewport
use Simplify in Rendertab to lower texture resolution for viewport


You can use snapping options to do that.

Set snapping on and choose the closest to vertex option (under the green arrow bellow)

Enter edit mode for one of the objects
Select all the vertices
Then point your mouse to the bottom of the second object and grab G

Now position the 3D cursor to the bottom : select one of the bottom vertices, then Shift + S and cursor to selected

Back to object mode
Set the pivot to 3D cursor
Then scale S and point to the top of the second object


Here I created an example Scene with your node Setup (without any glowing effects)

Here I just switched the positions at of the input the Alpha-over node and then it worked


You've stretched the sides in the uv map to be taller, but no wider, hence the stretch.

If you subdivide the sides it will just place the new vertex in the middle of the other two, with no interpolation, hence why it doesn't get smoother. Subdivide smooth or the subdiv modifier are much better than doing it yourself.


How can I make a number of objects sit "snugly" on an irregular surface?

This might not be as 'snug' as you might want but for the use case you described above, it is perfect. You can do this with a particle system and groups.

Group all your objects that you want to sit on the ground and add a new Particle system to the ground.

Change the type to Hair and under Render change the type to Group and select the group you had previously created, your objects will be scattered randomly across the ground.
(Note: This might lag your scene as the default Emission amount is 1000, so change it before or after).

I imagine this can be ideal for scattering rocks and or brush over some terrain. I won't go too indepth on the other settings as they are pretty intuitive and you will more likely get your desired results if you experiment. (larger image here)


I'll try to explain it in layman terms, hopefully it is not very far from the actual technical workings of a render engine. If someone with true programming inside knowledge wants to barge in, please do correct me if I'm wrong

While rendering Blender, and most rendering software for that matter, divides your image up into small digestible chunks, like buckets samples, or whatever method is more adequate for the current engine.

These chunks are then run through some sort of scheduling agent that queues them and sends them to the available processing units, be it a GPU, CPU core, one of several networked computers, a Farm or whatever.

The scheduler then waits for the processing units to churn through that data, produce the image slice and return them as rendered chunks to send in a new one afterwards.

Until that chunk is returned Blender has no control over that processing unit, all it can do is waiting for the returned information.

If you cancel a render Blender most of the time the only way to actually stop it is by not sending a new chunk, and even if a "cancel" signal can be sent, often the processing unit is busy and can't act on it until it finishes that chunk anyway.

The time until the signal is interpreted or the current chunk is finished is the delay you experience between pressing Cancel and actually stopping.

Following Scott Milner line of thought, the larger a render tile or bucket is, the longer it takes to render, so theoretically the longer the delay to cancel. The same applies for more complex algorithms like Branched Path Tracing which require more processing power and memory, and thus take longer to process.

Have in mind that lowering bucket size may negatively affect your render times, so you should weight the pros and cons of faster render or faster cancelling.


HDRI does not work properly after opening saved file

You can save the HDRI in Blender by going to the file tab in the upper left corner, and selecting external files. This will give you an option to pack all external files into the .blend so that you can save it in the file.


Difference between the scale and the size of a light in cycles?

My observation from Blender 2.68:

Changing the size from the properties also changes the size in the 3D viewport.
Changing the scale in the 3D viewport does not change the scale in the properties.

The rendered result is the same in both cases. The only difference is in how you see the light in the 3D viewport.

Conclusion:
Either use one or the other, but don't mix. If you mix, the actual size of the light is different from the one you see in the 3D viewport. Though it will not crash anything, it may become confusing.


Windows 7 here, and I use a desktop shortcut; You can download it, unzip to inside your "Blender Foundation" folder in Program Files, it shouldn't delete the other versions.  You will have to make a new shortcut on the desktop for the new version.  Then you can delete the Zip file, or keep it.


Intel denoiser is denosing every frame differently

It seems that the Open Image Denoiser currently does not support temporal coherence. That means it only considers one image at a time, not the surrounding frames. However, according to this issue at their repository, this feature is planned for a future release.
Same problem with the Blender denoiser (denoising option in the render layers tab):

For animation denoising can be used, however it still requires high
sample counts for good results. With low sample counts, low frequency
(blurry) noise can be visible in animation frames, even if it not
becomes immediately apparent in still images. (Blender Documentation)

Conclusion: It seems that your best option is to use more samples if possible (and search for tips to reduce render times). Maybe some of the tricks to reduce noise mentioned in the Blender Documentation can help you as well.


Make two objects out of two pieces separated by boolean difference modifier

You will need to Apply the boolean modifier (it's a button in the modifier panel), then use the Spacebar menu to find the Separate operator, and choose the "By loose parts" option.


How can i change a bolt head to pan type?

If the menu for the options is not visible you can access a floating window with the same options it by pressing F6

If the menu is not visible on the tool panel, then press the + sign at the bottom of the panel.

Note that you can only set the parameters at the time of creation of the object.

Modifications have to be done before you use any other tool. Once you made any kind of transformation (scale, move, rotate, etc, or selected another object) there is no way to get the menu back. At that point, the only way to change the parameters is by creating a new object.


Cell Fracture Issue | Cells appear werid

I had this issue too just right now and apparently scaling the object up before the cell fracture to a comically large size worked for me.


Why can't I get into Sculpting Mode with metaballs?

Metaballs need to be converted to mesh before returning to sculpt mode.
Object > Convert to > Mesh from Meta/etc


Blender renders circles instead of squares

Turn Off Subsurface Modifier completely.


I made a simple wreath by using a particle system to make the shape of the wreath and only modeling one branch object then distributing it around with the particle system (no combing the particles).

Start with a torus (I scaled it along the Z to make it thinner).
Add a particle system to that torus. All you really have to set in the particle system is the Type (set it to "Hair") Length, and the Number of the particles. There are 1000 strands my wreath.

The important part are the force fields. All the below force fields are in the exact same spot as the torus, except for the two wind ones.

First add a Vortex Force Field, this is to make the strands curve around in more of a wreath shape.
On the left is just how the particle system looks, and on the right is with the vortex force field.

Add a plain Force type force field. This is to enlarge the center hole in the wreath.
Add a Wind force field. Rote it so that it points up. Here you need to set the Maximum Distance so that the wind only affects the strands on the bottom. You want to adjust the strength so that it just pushes the strands on the front or back side of the wreath into shape.
When you have that one adjusted to your liking duplicate it ShiftD, move it to the top and rotate it so that it is pointing down.
In the image below the wreath on the left has no wind force fields, see how the strands stick straight out the wrong way. On the right is what it looks like after adding the two wind forces, the strands are smushed into a wreath shape.

Now model a branch, it can be simple, but keep the length about the same size as the length of the strands. Do note that the stem of my branch has loop cuts all along it (they are the only part selected). That allows it to bend along with the particle strands.

Add a particle instance modifier to the branch you just modeled. The reason I'm using this modifier instead of the more common method of just setting the object in the particle settings is because the particle instance modifier will deform the object, as opposed to the just rendering the object in the particle system, which will keep it straight.

Set the Object to the Torus we added first.
Then check the all important Create Along Paths checkbox. Because I have my branch along the Y axis, the Y axis is selected.

Granted you are probably going to need to tweak your wreath some. Any time you're using force fields to model something it can be rather finicky. For that reason my blend is attached. Look through it, copy the settings, learn from it.

Here is the full blend


Parts of my mesh are hidden when armature modifier is turned on

You get a twist problem on your "Track To" constraint on KneeCylinder.L / KneeCylinder.R.

(Try set influence of this constraint, and you will see your cylinder).

Quick fix by Rolling your bone by 180° (edit mode, and set roll to current roll + 180°)


I don't know exactly why your mesh is emitting as much fluid. First of all try to apply scale: CTRL+A > Scale.

And for full control over dripping you can use Speed value under Domain settings. Also you can change Viscosity preset to Honey/Oil, drips will be "heavier" thus slower.


This isnt the best way for this but it should work for what you need.

The problem with the set up below is the brown stick part is also illuminated not just the fire part. The best way to do that is to have 2 different materials one for the stick and one for the fire (with just the emission on the fire.) Or you could use a vertical falloff ramp but that may be overkill for what you are looking for. Hope the below set up helps you.

Or you can skip this whole step and just put a point light where your torch is.


How can I make drops of fluid hang from a surface?

Apply a strength 5 force field to both the fluid and obstacle. The fluid should probably have a low partial slip, and free flip on the object. I would be more precise if I had more time, but here's my result (see below pic). You can see particles starting to stick, then fall off near the very bottom.

How it works: Water molecules have a charge of attraction to each other (and solid objects) causing surface tension, which holds a drop together. applying the force field tries to imitate that effect.


For Cycles to render something, it has to have some kind of geometry for the light to interact with.  But particles are really just 0-dimensional points in space, by default they have no geometry.  So for Cycles to render them you need to give them some geometry.
You have several options under the Particle Settings panel > Render rollout as to how to render the particles:

None: the particles themselves are not rendered at all.  Use this option if you are using the particles just to control something else; such as a point density cloud, smoke simulation, explode modifier, etc.
Halo: the particles are rendered as small volumetric-like glowing points.  Note: this button only works in Blender Internal, to render halos in Cycles you must use point density clouds (see below).
Line: the particles are rendered as line segments pointing in the direction of their velocity.
Path: used for hair or keyed particles.
Object: the particles are rendered as instances of a specified object.
Group: the particles are rendered as instances randomly picked from a specified group.
Billboard: the particles are rendered as square planes whose normals always face the camera.

Point Clouds

Rendering halos in Cycles is a little more complicated (but way more flexible and useful) than in BI.  As stated above, you must use volumetric Point Clouds.
To set this up create a domain object (usually, but not necessarily, a cube) around the particles, make sure all particles you want to render halos are within the box (or use multiple domains).
Then give the domain object a volumetric emission material by plugging an Emission shader into the Volume Material Output socket.  By default this will simply emit light from the entire volume, so to tell it to only emit light from where there are particles add a Point Density texture node controlling the emission strength.

Here's an overview of the Point Density node's settings:

Particle System:  Use a particle system to control the point cloud.  Points will be rendered at the particles' locations.  (This is what you want.)
Object Vertices:  Use the vertices of an object  to control the point cloud.  Points will be rendered at each vertex of the selected object.
Object:  The object to get the particle system or vertices from.
Particle System:  The particle system from the specified obejct to use for the point cloud.
Space:  If you want the halos to be rendered exactly where the particles are in the scene use World Space.  If you want the particles' locations to be scaled down and moved to fit in the domain object use Object Space.  Most of the time you want World Space.
Radius:  The radius of each individual halo.
Interpolation:  The interpolation method between voxels.  Cubic or Linear usually works best, Closest gives no interpolation.
Resolution:  The number of subdivisions (voxels) in the volume.
Color Source:  The property value to send to the Color output socket.


Subclassing property group class problem

Only use bpy.types.PropertyGroup for the registered class type.

The property group and bpy.props properties are wired up as properties through the "rna voodoo magic" internally with blender when registered.

Similarly as often seen with operators and panels, only give the registered class the type you are registering. For want of a more technical description.  Refered to as "Mix in classes" in panel link

eg below the B propertygroup class inherits A.  All annotations of B and A become properties of the pointer property instance..

import bpy

class A ():
    x : bpy.props.StringProperty(name = "X", default="Foo")

class B (A, bpy.types.PropertyGroup):
    ind : bpy.props.IntProperty(name = "Prop")

#bpy.utils.register_class(A)
bpy.utils.register_class(B)

bpy.types.Scene.testvalue = bpy.props.PointerProperty(type=B)
print(bpy.context.scene.testvalue.x)

#bpy.utils.unregister_class(A)
bpy.utils.unregister_class(B)

Prints "Foo" to the system console.


How to render an object without its shadow?

One option is turning off the Shadow property per object (Properties > Object > Cycles Settings):

As of Blender 2.8x the Cycles Settings panel has been renamed to Visibility and the Shadow property is now part of the new Ray Visibility subpanel. For Eevee you can only turn off the Shadow property per light for the time being (Properties > Object Data > Light):

Another option for Cycles is using the Light Path node. Plug Is Shadow Ray into the Factor socket of a Mix Shader and use a Transparent BSDF for the second Shader input:

Result


How to have a rigged object snapped to another object's surface?

1 Shrinkwrap Constraint
Add an intermediate bone as a parent of the Hand: Arm > HandParent > Hand.
Then add a shrinkwrap constraint to it using the options Projected, On Surface along +Y in Local Space.
The HandParent will be projected onto the surface of the object, which you select in the Shrinkwrap Constraint.

2 Bone Placement
An easier option, is to simply place the arm bone at an appropriate base position, so that the arc it describes resembles the arc of your sphere. This is less computationally expensive and faster to setup. Add a custom bone shape and the bone will not be in the way as well.


I got this problem with animating, when I switch frames, the pose of reverts

Okay this is weird, I inadvertently solved the problem, it was apparently a glitch after all. What I did was changed the timeline to the idle animation to make sure it wasn't messed up too. And when I changed back to the timeline of the messed up animation it was working properly all of a sudden. To think I wasted a weak not getting my project done because of this problem and that was all I had to do.


How to position solid objects so they're attached, ie links on a metal watch strap?

I figured it out. I thought I'd share the solution. It was a lot simpler than I thought. I left the outer pairs as seperate objects, and inner links as seperate objects too.
Then, I added an armature, went into edit mode and positioned the ends at either end of the strap.
Then I subdivided (W) the armature in edit mode a few times until there was enough bones for each segment.
Then I went into pose mode. Selected the left most link, then shift selected the left most bone. Ctrl+P, parent to bone. Then I continued doing that for all the segments of the strap.
Then, in pose mode I selected the last bone and went to Add constraint, IK solver. That's it.
Now when I move that last bone in pose mode everything follows it sweetly. PS this is in blender 2.49b but it will be very similar in later versions I'm sure.


(2.8/9XX) Addons show up in the list but not in the interface!

one of areas on screen you have to change to type Sverchok


You can manually select the faces you want to separate (or entire continuous chunks with Ctrl+L) then break up the meshes by pressing P while still in Edit mode then choosing "Selected".


In default settings, AN rebild scene "always", that means that AN invoke your set up as many times as it possible.

Instead of this, try the setting, whan AN will be invoke nodes only if something changed:

It's more friendly for CPU, and faster for workflow..


I figured it out! For some reason you cannot have "Freestyle SVG Exporter" and "Freestyle" both enabled in the render properties. By unchecking "freestyle SVG exporter", I finally could see an outline!


How can I fix the black parts after I apply subsurf?

It might be because the vertices in the mesh are not made properly positioned that the blender is not able to properly calculate how to apply the modifier. So try these:

Recalculate the normals properly using: "Shift+N"
Go to edit mode and remove duplicate vertices by "Merge by distance
option" (make sure you set the proper distance in the dropdown menu). Also, make sure
that there aren't overlapping faces


Volumetric lighting is not showing in camera view

Select your camera in order to change your render settings. Change the clipping end to a bigger number.


Blender's viewport has limited support for generated and object coordinates.

GLSL preview materials only support a subset of Blender node material textures and features as stated in this bug report and this one too

You can fake it or workaround it using node materials, as shown in this video


Change the size of cylinder/rope in realtime (GameLogic)

Created two "endpoint" objects that move in gamelogic mode. Then grab their center location do some geometry and python code changes the cylinder (rope). only used one endpoint in the code below as the other endpoint was origin (0, 0, 0). Also note that this only watches one plane (x and z axis).

#get endpoint center location
boom_endpoint = boom_point.worldPosition

#get distance between endpoints
y_pow = (boom_endpoint[2])**2
x_pow = (boom_endpoint[0])**2
rope_distance = math.sqrt(x_pow + y_pow)

#scale value for axis that need to be stretched
new_scale = rope_distance/2

#angle between endpoints to rotate the rope
angle = math.asin(boom_endpoint[2]/rope_distance)
rope.localOrientation = rope.localOrientation * mathutils.Vector((math.radians(0), angle, math.radians(0)))
#apply scale and location changes
rope.localScale = mathutils.Vector((1, 1, new_scale))
rope.worldPosition = mathutils.Vector(((boom_endpoint[0]+0)/2, 0, (boom_endpoint[2]+0)/2))


How to create a gradient backround in the compositor?

Add a Texture Node with a blend texture and color ramp. You can adjust the gradient using the Color Ramp in the Textures panel. (See image)


How can I fix this? Blender Mesh Problem

Just in case it is not clear to you how to "unhide" "the solidify modifier in edit mode"
I am adding an screen shot to illustrate Robert's comment. :)


Reducing vertex density as distance from point increases

If all you need is to reduce vertex count, and not care much about the topology, you may consider use Decimate modifier, and control the modifiable area by vertex group.

Method 1:

Method 2:

Select the ears, then CTRLI to select the invert part;
X > Limited Dissolve to dissolve elements for mesh simplification in a relatively cleaner way.
Press F6 for further tweaks.

P.S.: Limited Dissolve gives same result as the Decimate Modifier by using its Planar mode. So you can use both.

(Head model came from Sintel project)


Objects transformations wrong when importing from 3ds

Select them all (they are selected by default after importing), press AltS, AltR and AltG to clear all the transformations.(Or go to the header menu > Object > Clear to find these operators.)

P.S.: If the result still problematic, try toggling off the Apply Transform in the left-hand panel in the Import window.

By doing so, The origins of all objects will go to one point. If you want move each origin to their individual geometry, just keep them selected, then press ShiftCtrlAltC, choose Origin to Geometry or Origin to Center of Mass to move them back to each individual objects.