text:
Blotchy noise in cycles render with denoise
When I was rendering my image, I noticed that it looks weird (top left, and right side). I don't know what causes this issue, never had it before.

useful info/settings:
samples = 256
I render using my CPU
Max light bounces = 12
Denoising on def settings
Thanks.

I edited your post to embed the image, but next time please use the "add image" tool in the post editor...

I have had the same with the denoiser when an area has had a high frequency noise. The denoiser can't know what pixels are fireflies and what are correctly calculated pixels. It just looks at the pixels and see a lot of white dots and think it’s the real thing. Same thing happens here where you have a high frequency texture and the denoiser considers an area that is too large into account when denoising.
Try setting the radius to something low, like 4 and the strength down to .2. Another alternative would be to deactivate denoising for diffuse direct to see if that helps. But I have never tried that.


text:
Replace video content within a Blender animation in Other Video Editors
I'm using blender to composite a video within a spinning glass rectangle. Is there anyway I can render out the animation from Blender and replace the video content within AE, but still keep all the glass reflections on the video? it would cut down a lot of render time...

Yes.  The trick here is rendering out multiple layers so that you can re-combine them later, elsewhere.  In Blender, this utilizes Scenes, Links, and Render Passes.
Create and Animate your spinning card as you would normally.  Then, Create a new scene.  Click the camera and press ctrl+L to bring up the links view.  Link the camera in the scene you just created.  Select the glass object that houses your picture and disable the video.  Link it like you did before to the new scene.  The objects you linked will now exist in both scenes.  Duplicate the glass object in the original scene and delete the original glass.  On the duplicate glass, either give it a knockout material or a solid unshaded color you can use to chroma-key, this will depend on the other program.
You now have a scene that consists of the frame and something to key off of when inserting a video, and a separate glass effect you can overlay on top the chroma effect.
This isn't free though:

With Blender now out of the picture when it comes to the 3d transform of the frame, you will now need to motion-track the frame video you render out if you want the video to not appear to be a window when you composite the video in.  You also lose any dynamic lighting that the video may have once provided.

You will likely want to render out the Z-Depth of the original scene so you can decide when the video should be occluded correctly.  Most compositors worth their salt will be able to use this info.

If you want to see some of the concepts in motion, I recommend this video that briefly discusses multi-scene renders: https://youtu.be/r7G13NPvXuc.

Thank you @kirbinator. I came across a plugin that ideally should help me transfer position data from Blender to AE - https://www.youtube.com/watch?v=XaQCkSzy2YA - but if that doesn't work I will follow your advice.

source: Stack Exchange

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

sort: votes


text:
HardOps: Is there a modifier pin option?
I was wondering if there is a way to pin a modifier to stay last or first in the modifier stack; I use Hardops and it usually forces the bevel modifier to stay last even if you add booleans and such, but when introducing vertex groups it want do that anymore, so regardless if there is anything I would appreciate the help!

If you want a certain type of modifier to float to the top, you can mess with HardOps's options.  From there you can choose which modifiers are sent to the bottom of the stack when added, otherwise they'll stay where they land.

From the same window you can also set an ignore flag (by default: a space before the modifier name), which will leave that modifier alone and not consider it as part of the HardOps sort modifier settings.
The following is a link to HOps's semi-official YouTube manual explaining how it works: https://www.youtube.com/watch?v=KfIqWv5LFvo

thank you for your reply, but it seems that it does not work, nothing changes when i toggle off the ' Ignore Bevels with VGroups ' in both Hops and Boxcutter, the booleans still are not sorted as intended, No clue why !

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


text:
Where is the UV Warp? Is it in UV Editing Tab?
I've heard of "UV Warp", that can allow me to edit and animate a Texture the Eyes of my model.
But I have no idea where it is in UV Editing, or how to get it.

This is my setup, and this is how it is in UV Editing.

: ( ... this is in the modifiers tab. This time, I won't indicate to close this """new""" question, but please this site is not to teach all from a to z. Read the documation: https://docs.blender.org/manual/en/latest/modeling/modifiers/modify/uv_warp.html

Again this should meet your need https://blender.stackexchange.com/questions/55295/creating-an-eye-eyelid-rig-for-dragon-without-shape-keys/55296#55296


text:
Making a portal effect in Cycles
Case
I followed this outdated tutorial to create an effect that I want (being able to see a completely different world through an object (a shield in this case). I got this to work in blender 2.8+.
The problem is that I have to render in cycles due to some nodes being used and these are only available in cycles. At the moment blender renders all 3 layers and smacks them together to generate the desired result which takes 3x as long. so my question is:

How can I preview this effect without having to render it?
How can I tell blender to only render 1 layer to preview other effects?

Here are some screenshot of my project, hope it helps.

Shiled being used as mask

other dimension I want to capture by watching through the shield

https://blender.stackexchange.com/questions/137679/portal-effect-in-eevee

you can use the search box at the top for commonly asked questions https://blender.stackexchange.com/questions/61965/creating-the-minecraft-end-portal-in-blender


text:
How to implement an automated render farm with remote access?
I'm in a bit of a fun spot where I have full access to a VR arcade and a couple dozen GPU's inside it. Each of the computers is running Windows 10 and is on their own high speed internal LAN with a NAS.
In my spare time, I've been dabbling with small Blender animations as a hobby and wanted to utilize the processing power of the arcade at night to speed up render times. So my question is, how would I best go about doing that from outside of the network, without installing anything that would disrupt the regular operation of the arcade?
It's worth noting I can turn on/off the computers remotely, but not dual-boot into Linux remotely. I can also VNC into the individual computers, but I'd rather things be automated than have to start blender or some other other software on each computer each time I want to render something.
I've tried several solutions, including a Flamenco server, using third party plugins like CrowdRender, Prism pipeline's Pandora, etc. But they're all way over-complicated or only work on local networks. I ended up finding myself sinking more time into setting up the distributed rendering than I did actually animating, and gave up for a while.
Instead of trial and error or reinventing the wheel, I figured someone here would have experience with something similar or be able to suggest software that'd help out, or suggest I retry certain software I've already tried before.

If they are connected to the internet, try Sheepit. If you run their client on each computer they will render for the farm and if you upload a project it will first be rendered on your own hardware so easy to setup, everybody wins. Unless 500MB file size limit is too little for your scenes and you want to use exr output with passes and render layers instead of only png that Sheepit supports. But it has the advantage of being very easy to set up.
If I am not mistaken, some of their software used for the farm is open source as well, so it's worth exploring if it may be possible to use it to setup your own farm as well.


text:
Question about smoothing issues to the model
I imported a tank model from a game, extracted with Ninja Ripper. The model has some smoothing issues while even if I tried select the mesh and soft all verts, faces and edges in shading panel, the mesh still looks weird.
Also tried the auto smooth option. I'm not quite sure the faces are in this look due to only smoothing or also the flips or something inverted. With ⌃ Ctrl + N I did found some of the faces on the turret turns different while some are not.

I don't know if it has something to do with flipped normals so I recalculated the normal with ⌃ Ctrl + N or ⌃ Ctrl + ⇧ Shift + N and this is the output:

In Object Data > Geometry Data, try Clear Custom Split Normals Data

Thx! But I checked the geometry data and the only one option can be used is Add Custom Split Normals Data.

so maybe share your file or at least a part of it? https://pasteall.org/blend/

Thanks a lot! The file is here: https://pasteall.org/blend/dfa2cd18c9074d2791cfc060efe47df2

You need to do 3 things to get a clean shading:

You have sharp edges, so, in Edit mode, CtrlE > Clear Sharp
You have overlapping vertices, so, Edit mode, select all and (in 2.79) W > Remove Doubles
As I said, in the Properties panel > Object Data > Geometry > Clear Custom Split Normals Data

thank you so much! However ummm there's only a Add Custom Split Normals Data on my end in the panel. https://imgur.com/a4tUzEh

that's weird because I had the Clear button and I had to use it...

Can you help me to fix that? I tried reload a raw file but still Blender did not provide that option to me. Is it possible for you to fix and then send the the file in .obj to me? Thanks!

sure, here it is, tell me if it works: https://pasteall.org/blend/529e1517ccc34bb7aadfe3b3b859bdd8

Thank you so much! It is perfect! You saved my day!


text:
How do I override context for new OBJ Importer? (bpy.ops.wm.obj_import)
I'm trying to import an OBJ file while rendering an animation, during the frame_change_pre event. The purpose is to stream a sequence of meshes into Blender, one at a time just before each render. I've successfully done this in Blender 3.6 and earlier using the Legacy OBJ importer (bpy.ops.importer_scene.obj()), but I'm running into problems with Blender 4.0 and the new OBJ importer (bpy.ops.wm.obj_import()). I keep getting the error:
RuntimeError: Operator bpy.ops.wm.obj_import.poll() failed, context is incorrect
Looking at the Blender source code (source/blender/editors/io/io_obj.cc#L488), I've found that the poll function is the WM_operator_winactive function. This function, as far as I can tell, simply checks for an active window, but correct me if I'm wrong.
I've tried using the bpy.context.temp_override() function with no success. I'm not sure how to override the context. How can I override the context for this specific case? Or what workarounds might exist?

There are no Blender developers here, nor does anyone here work for or have any association with the Blender Foundation. Since that addon is now written in C++ which we can't help with here, rather than python, I'd suggest you ask in a Blender developer forum, maybe at https://blender.chat/home .

@JohnEason I don't see why that means I can't ask the question here.

I didn't say that you couldn't just that you're more likely to get an answer in a developer forum.

I'm unfamiliar with Stop Motion OBJ but I was running into problems with bpy.ops.wm.obj_import() in 4.0 too, but now with 4.1 it's working for me, though I'm not sure if something changed.
If the problem still persists, then I would suggest to setup a simple for-loop that imports the next obj from a sequence and then renders an image on each loop, because the stream function may have been written to work with the legacy importer, and there are still some differences between the two importers. At the very least, this might help you debug the issue, I hope.


text:
Is it possible to render frames out of order?
I have a looped animation. On the first and last frames, there is nothing but a plain backdrop, and the object appears sometime during the middle of the animation. I'm rendering to an image sequence, then compiling to .gif with the help of ScreenToGif.
The problem is that the .gif thumbnail shows the first frame, which is the blank backdrop. This is especially problematic because I have multiple works in a series, and all of their thumbnails are the same blank backdrop. The animations are all 168 frames long. My workaround is to manually import frames 60-168 into ScreenToGif, then to import frames 1-59. However, this is fairly inconvenient. I've also tried shifting the keyframes to achieve the same effect but, again, it's a substantial amount of unnecessary work.
Is there a way to render frames out-of-order and effectively renumber or remap the frames? For example, I'd like to save frames 60-168 as frame[0001-0108].png, and frames 1-59 as frame[0109-0168].png.
Is this possible?

There is no frame offset property. You would have to rename the renderings using python when finished. An automated way I can think of is copying the files into a new folder by specifing the 'split frame' and create the gif by using ffmpeg. Would this help?

I would also do it with scripting. This solution renames already rendered files. It reads most stuff from your Blender settings - but it also assumes those settings are correct and didn't change since you rendered the files. It also assumes there's no additional files other than those rendered in the render directory!
Running the script once will shift the frames by specified number (I've set it to 100) - you could also uncomment line 11 to shift by half of the animation, so it starts exactly in middle.
Running the script a second time will unshift the frames back.
I just wrote this script so it's not thoroughly tested.
import bpy, os

offset = 100  # that many frames will be moved from the end to the beginning
shifted = "shifted"  # base of filename after shifting

scene = bpy.context.scene
path, orig_base = os.path.split(scene.render.filepath)
start = scene.frame_start
end = scene.frame_end
anim_len = end - start + 1
# offset = int(anim_len/2)  # set offset to half of the animation

for i, filename in enumerate(sorted(os.listdir(path))):
    base, ext = os.path.splitext(filename)
    if base.startswith(shifted):
        # restore
        new_frame_num = start + (i-offset) % anim_len
        new_filename = f"{orig_base}{new_frame_num:04}{ext}"
    else:
        # shift
        new_frame_num = start + (i+offset) % anim_len
        new_filename = f"{shifted}{new_frame_num:04}{ext}"
    print(f"Renaming {filename} to {new_filename}")
    os.rename(os.path.join(path, filename), os.path.join(path, new_filename))

Don't worry, looks nice and should work fine.

I would do this via scripting.  Here I modified an existing script that would do your remapping of frame# into file index#.  You would adjust firstBreak to 60 and lastFrame to 168.
import bpy

filepathFmt="//render/frame {0:04d}.png"

firstBreak=8
lastFrame=11

###
### for list of shape types, N loops, create a set of objects, render and save, and clean up:
###
fp=""
outFileIdx=1

### render from firstBreak to lastFrame:
for frameIdx in range(firstBreak, lastFrame+1, 1):

    bpy.context.scene.frame_set(frame=frameIdx)
    print("frame=" + str(frameIdx))
    # format filename string using different index
    fp = filepathFmt.format( outFileIdx )
    print(outFileIdx)
    print( fp )
    bpy.context.scene.render.filepath = fp
    bpy.ops.render.render( write_still=True )
    outFileIdx+=1

print("remap")

### render from frame 1 to firstBreak-1:
for frameIdx in range(1, firstBreak, 1):

    bpy.context.scene.frame_set(frame=frameIdx)
    print("frame=" + str(frameIdx))

    ### render and save:
    # format filename string using different index
    fp = filepathFmt.format( outFileIdx )
    print(outFileIdx)
    print( fp )
    bpy.context.scene.render.filepath = fp
    bpy.ops.render.render( write_still=True )
    outFileIdx+=1
```


text:
Cycles - What is the expected range of values for Displacement?
Let's say I have the following [kinda boring] shader setup:

For what output values of the Voronoi Texture will the surface appear to be displaced outward? How about inward? In Houdini, negative values displace inward, positive values displace outward, and values of 0 don't displace at all. Is it the same in Cycles? Or is it a different range?

In Blender 0.5 is no displacement, 0 is inward, 1 is outward. But note that this will not displace the actual surface, it is just a Bumpmapping effect. Thus what is the 'no displacement' level is hard to tell.
To get real displacement you have to apply a 'Displace' modifier to the object. Here you can actually define what value is 'no displacement' and how sttrong the displacement is. Just make sure it is tessellated enough. Add a Subsurf modifier above for example:

The comparison of displacement in shader (left) to displacement using modifiers (right):

Edit:
As @gandalf3 mentioned in the comments, true displacement using nodes is available in cycles as an experimental feature. To activate it, first enable the 'Experimental' feature set in the rendering options:

Then go to the object data panel and set the displacement method to 'True' (1). This will give the same effect as adding a Displacement modifier to the object. To also get the fine tessellation effect of the Subsurf modifier enable 'Use Subdivition' (2). The 'Dicing Rate' controls how fine the mesh is tessellated.

However this method seems to displace the faces independently, which can lead to gaps in the surface:

Thanks for the answer. So in your example, where does the Displace modifier get its Voronoi texture? Do I have to create a texture 'object' or can I tell it to grab a texture from somewhere in the shader network?

As far as I know you can not access the cycles texture node from outside the shader. You have to use a texture object. You can see my .blend file for reference. In my file I also added a Texture Coordinate node to the shader to give both textures the same coordinate system. Otherwise the texture in the shader is twice as large as the one used for displacement.

That kinda stinks. Sometimes I like to do all sorts of masking/adding/subtracting/multiplying to a noise pattern in the shader. It would be nice to have that functionality in a displacement texture also.

@Justin Cycles supports real displacement too, see http://blender.stackexchange.com/q/1719/599.

@gandalf3 nice! I guess I should play around with the experimental features from time to time :)

If you use a subserf modifier instead of the cycles dicing, the faces won't split apart.

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


text:
How to generate a Transparency "Gradient" Shader?(Eevee)
Using the  setup below ,a transparent gradient shader does not get generated.
How to generate a Tranparency "Gradient"  Shader in Eevee?

UPDATE 1

Tried the below 2 solutions by @Moonboots but was not getting the same result.  Also checked switching Blend mode to Alpha-Blend and unchecking 'Show Backface' ,but not getting transparency.What's missing?

If you are using EEVEE, you need to change the Blend Mode of the material. It's in the material properties tab. Change to anything other than Opaque (I find Alpha-Blend works nicely for most situations).

please share your last file

Blend file uploaded(plz find in above question)

Gradient Node has to be connected first to the alpha socket and then the Color ramp node  inbetween.

I'm not sure to understand your node organization, in my opinion you should choose between the alpha and the transparent solution, which would give the ColorRamp plugged into the Alpha socket:

or the ColorRamp into the factor of the Mix Shader between the Principled BSDF and the Transparent:

Also, maybe deactivate the material Show Backface option?


text:
Importing Another Scenes Audio in Sequencer
Blender 2.93/Windows10
I have multiple scenes animated and synced to their own  audio clips( imported in their respective Sequencers).
However,on importing all these individual scene into a Main Scene (say a Sequencer_Scene),
the Sequencer_Scene doesn't import and play the audio of these individual scenes(but shows the 3d_Camera output fine).
Is it possible to import another Scenes Audio in Sequencer_Scene?
Also,is there a way to play the Audio from the Sequencer_Scene in other scenes(for animation syncing)?

I had that problem before and never found a way around it. It seems like when it comes to audio, Blender only ever considers the current scene and nothing else.

I have raised an issue :https://blender.community/c/rightclickselect/NOXK/?sorting=hot


text:
Bmesh - Append selected vertices to a List (Working script not "Reloading" correctly)
In Blender2.79,the script below calculates the selected vertices and stores them in a list.
As there were issues with calculating these vertices directly on a mesh instance ,the object's mesh had to be converted to a "bmesh" instance.
When the script is run it works fine in the "First run".
But in the subsequent runs it gives the following error- AttributeError: 'bytes' object has no attribute 'verts'
Also,on updating the bmesh with bmesh.update_edit_mesh(me)results in this error-  ReferenceError: BMesh data of type BMesh has been removed
How to resolve these bmesh errors?
#-------------------------MAIN SCRIPT--------------------------
#Select vertices of default cube in Edit mode

from os import system
system("cls")

import bpy
import bmesh

scene = bpy.context.scene
ob = scene.objects.active
vert = ob.data.vertices

#Set default mode == Edit
if bpy.ops.object.mode_set.poll():
    bpy.ops.object.mode_set(mode='EDIT')

print("Active object = ",ob.name)
print("")

#Create Bmesh instance and calculate vertices
print("Vert_selected")

me = ob.data
bm = bmesh.new()
bm = bmesh.from_edit_mesh(me)

vert_selected = [v.co for v in bm.verts if v.select] #AttributeError: 'bytes' object has no attribute 'verts'
for vs_s in vert_selected :
    print(vs_s)

bpy.ops.mesh.select_all(action='DESELECT')
bm.select_flush(True)

#bm.bmesh.update_edit_mesh(me) #If mode ==Object  -> ReferenceError: BMesh data of type BMesh has been removed (Uncommenting results in Blender crash)
bm.free()
ob.update_from_editmode()

print("Script exited")

Recommend Don't access Mesh.vertices in edit mode.  use edit mode bmesh for this. Can update the mesh from editmode with context.object.update_from_editmode() If using foreach get it returns a list of values eg [True, False, True, False] .  The list needs to be correct size.v_selected = [False] * len(verts) and is populated (not resized) by the call.  Use if v.select:  no need to check against True

On using the Bmesh module  on a existing object , only to check for selected vertices gives an error refer- https://blender.stackexchange.com/questions/178938/convert-existing-mesh-to-bmesh-attributeerror-module-bmesh-has-no-attribut  .However , on  creating a new vert on a selected mesh using Bmesh module works fine .Should Bmesh be only  used when creating new verts ?

No Re the refer, I would accept the given answer. There is a big difference between a bmesh instance and the bmesh module.  There are countless examples of using edit mode bmesh to select or read selection.  Once again accessing Mesh.vertices in editmode is not the way to go. Blender makes a "mesh copy" to edit in edit mode, then writes back on mode toggle.  An edit mode bmesh is bound to the edit mesh.

I have already implemented the answer in my other question and am getting the errors(refer attached image).Already used edit_mode_mesh(),it does give the selected vertices but it also gives the following error;- AttributeError: 'BMesh' object has no attribute 'bmesh' on update_edit_mesh().The Bmesh is  set free() after this update command .Is  there any way to override this error?

I have posted the issue's with using Bmesh in the above question.

Recommend using autocomplete in the python console. You import bmesh if you then bmesh = something_else when you go to use it again, thinking it's the bmesh module ...   (bm is commonly used as a bmesh instance)  it is something else. Would look to stackexchange et al for the meaning of python errors.  Can get to The attribute error above bm =  bmesh.new() and then trying to use  bm.bmesh  Most of these errors are well explained and easilly  fixed by searching python AttributeError

Since there was no change in the actual mesh,updating the mesh with update_edit_mesh() was not required.Also setting object context directly to "Edit"mode as opposed to a context mode_set poll() works.
Code can be found here.


text:
Convert "Existing" Mesh to Bmesh (AttributeError: module 'bmesh' has no attribute 'from__mesh')
In Blender2.79, the "Main Script" below converts an existing mesh(default_cube) to a "Bmesh" (using bmesh.from_mesh()) and stores the selected vertices of the mesh in a list.
On testing,this Bmesh example(create new vert on existing selected Mesh) works fine.
However,when run the MainScript in both Edit and Object(after calculating selected vertices in edit mode) modes ,the console gives this error.
AttributeError: module 'bmesh' has no attribute 'from__mesh'

Since,the selected object has to be accessed as a part of the "active" scene, assigning object in this manner ,gives above error
scene = bpy.context.scene
ob = scene.objects.active
me = ob.data
bm = bmesh.new()
bm = bm.from_mesh(me)

Also direct context assignment gives above error.
ob = bpy.context.object
me = ob.data
bm = bmesh.new()
bm.from_mesh(me)

[![Bmesh.from_mesh() error][2]][2]
However, "from_mesh" is a valid attribute in Bmesh module.
Even using bmesh.from_object() gives a similar error.
AttributeError: module 'bmesh' has no attribute 'from__object'

Also,if bmesh.from_edit_mesh() is used , and even if the selected object is in Edit mode ,the console gives the following error(even if the Bmesh is set_free after this line)
ReferenceError: BMesh data of type BMesh has been removed

How to run this script in EDIT mode using Bmesh module (without getting any errors)?
----------------------------------MAIN SCRIPT-------------------------------
from os import system
   system("cls")

import bpy
import bmesh

#Assign object as a part of the active scene
scene = bpy.context.scene
ob = scene.objects.active
vert = ob.data.vertices

#Set default mode == Edit
if bpy.ops.object.mode_set.poll():
    bpy.ops.object.mode_set(mode='EDIT')

print("Active object = ",ob.name)

#Store selected vertices in a list
print("vert_selected")
#ob = bpy.context.object #Also direct context assignment raised no attribute error
me = ob.data
bm = bmesh.new()
bm = bm.from_mesh(me) #AttributeError: module 'bmesh' has no attribute 'from_mesh'
#bm.from__object(me) #AttributeError: module 'bmesh' has no attribute 'from__object'

vert_selected = [v.co for v in bm.verts if v.select]
for vs_s in vert_selected:
    print(vs_s)

bpy.ops.mesh.select_all(action='DESELECT')
bm.select_flush(True)

bpy.ops.object.mode_set(mode='OBJECT') # if bmesh.from_edit_mesh() --> mode == EDIT - ValueError: to_mesh(): Mesh 'Cube' is in editmode

bm.to_mesh(me) #If mode ==Object  -> ReferenceError: BMesh data of type BMesh has been removed
bm.free()
ob.update_from_editmode()

List selected edit mode vertices.
Run the script with a mesh in edit mode.  Prints an index list of the selected vertices.
An edit mode bmesh is bound to the edit mesh. The selection is live.
import bpy
import bmesh

context = bpy.context

ob = context.edit_object # RUN IN EDIT MODE
me = ob.data
bm = bmesh.from_edit_mesh(me)

print([v.index for v in bm.verts if v.select])

because we have not changed anything, only read selection there is no need to update the bound mesh.

Why use v.index(last line) ? Since actual location of verts is required ([v.co for v in bm.verts if v.select]) would be better.

A changed the way you selected active object and the way bmesh.from_mesh was called.
from os import system
   system("cls")

import bpy
import bmesh

#Assign object as a part of the active scene
scene = bpy.context.scene
ob = bpy.context.object
vert = ob.data.vertices

#Set default mode == Edit
if bpy.ops.object.mode_set.poll():
    bpy.ops.object.mode_set(mode='EDIT')

print("Active object = ",ob.name)

#Store selected vertices in a list
print("vert_selected")
#ob = bpy.context.object #Also direct context assignment raised no attribute error
me = ob.data
bm = bmesh.new()         # Create a new bmesh container instance
bm.from_mesh(me)         # Pass your mesh into this container

vert_selected = [v.co for v in bm.verts if v.select]
for vs_s in vert_selected:
    print(vs_s)

bpy.ops.mesh.select_all(action='DESELECT')
bm.select_flush(True)

bpy.ops.object.mode_set(mode='OBJECT') # if bmesh.from_edit_mesh() --> mode == EDIT - ValueError: to_mesh(): Mesh 'Cube' is in editmode

bm.to_mesh(me) #If mode ==Object  -> ReferenceError: BMesh data of type BMesh has been removed
bm.free()
ob.update_from_editmode()
```

Has this script worked for you in more than the" First run"?

i get Active object =  Cube vert_selected <Vector (1.0000, 1.0000, 1.0000)> <Vector (1.0000, 1.0000, -1.0000)> <Vector (1.0000, -1.0000, 1.0000)> <Vector (1.0000, -1.0000, -1.0000)> <Vector (-1.0000, 1.0000, 1.0000)> <Vector (-1.0000, 1.0000, -1.0000)> <Vector (-1.0000, -1.0000, 1.0000)> <Vector (-1.0000, -1.0000, -1.0000)>
Everytime I run I get this.
I'm not using system("cls")

That's why you are getting the same output everytime.System("cls") clears the screen to show the new output  in the next run.Follow these steps -1 Retype the System("cls") command 2.Enter Edit mode and select some vertices on the cube 3.Check console output if the script is showing the correct selected vertices 4. Run the script a few more times with newly selected vertices and check is the console is showing the correct output for each run.

As the context object's vertices where selected in "Edit" mode, the correct command to convert mesh to  Bmesh should be from_edit_mesh(), as opposed to from_mesh() which accesses the mesh datablock( as used in the above code).

There is no issue. The error is (most likely) because of unnecessary mode switching. Switching to object mode kills an edit mode bmesh because the data (edit mesh) is lost.

If the context is kept in Edit mode  ,the console gives the following error ValueError: to_mesh(): Mesh 'Cube' is in editmode

Consider using bmesh.update_edit_mesh(me) to update to mesh changes from an edit mode bmesh. And that's bmesh the module not some other variable you may have named bmesh.


text:
partical violin sticks out of test tube, how to stop it?
I have a test tube, in it, it has a ParticleSetting and the object is a violin but the head of the violin is sticking out of the test tube body and I want it to collide the hole thing with the test tube.
What do I have to do so it wont stick out?

Do you have any physics enabled?

my physics is fluid type and a little bit of damp.

I mean, do you have the test tube set as a collision object?
Share your .blend file here: https://blend-exchange.giantcowfilms.com/


text:
What is the point of pinning the UVs?
I've seen in tutorials - people are streightening and pinning their UVs - I really struggle to understand how it works and the reason - why are they doing this.
Doesn't it spoil UVs somehow if I move the points? I really would be grateful for explanation because it seems , that this process improves the quality of final texture.

In understanding the purpose of pinning, I found the following question useful - specifically the first two answers:
How do I straighten UV maps?
When unwrapping a complex model, I rarely do it in a single step. My workflow tends to be something like:

Mark some seams
Unwrap the model
Straighten some edges/manually move some UVs around to line them up the way I want
Realise I need another seam, so go back to the model to add more seams
Unwrap again
Continue aligning the UVs
...

Without pinning, when I unwrap my model a second time the UVs I have already manually edited will move. By pinning the parts I know are correct I can unwrap again and only the unpinned UVs will be recalculated.
This is especially useful because the unpinned UVs will be distributed according to the position of the pinned UVs. So by pinning a few key UVs, the next time I unwrap I'll get a result that is much closer to what I'm trying to achieve.
The second answer to the question I linked above gives a good example of this workflow.


text:
Skin is pulled to one side - using X-Muscle in Blender 2.8

Hi!
I am creating my first Blender-Model, using the add-on "X-Muscle-System" in Blender 2.8.
I don´t know how to solve the "yellow" issue: The skin is pulled too much to one side (when moving the armature to this position).
I think I need to renew the weights in weight painting.
Unfortunately, I have no idea how I should change them without getting hard cuts and how to make it smooth, respectively, do I have to expand or limit the tibia-vertex group and do I have to set the value closer to 1 or closer to 0?
Would it work better by using Python in Blender?
Can anyone help me, please?
Further information:
I am using the Blender add-on called "X-Muscle-System" this works fine. I created Micro-Controllers and now set the "skin tension" to Zero. Therefore, this is not influencing the Skin anymore.

Could you ever solve this issue?


text:
Deform mesh without any modifier and shapekey: how is it possible?
This is a mesh created by an addon called X-Muscle System.
This question is not about how to use X-Muscle System but about how to implement this effect in Blender, without using modifiers. It's to explore the possibilities of Blender. The addon is a working example I found.

I can drag the control point (an empty) around, and the mesh will deform along with it.

But it doesn't have an armature or any kind of deform modifier. Actually, I removed all the modifiers/shapekeys/vertex groups. And I uninstalled the addon itself. But it still works!
How does the X-Muscle System addon work?
What's the magic behind it?

It's just the bone.
You can parent a mesh to a bone and the mesh will follow the bone. That is, the bone controls the location, rotation, and scale of the mesh. It's good for armor, or make a bone control an eyeball to follow a target. It's also good for amination actions.
The magic here is the scale. If you scale the bone, it scales the mesh. Bones can have Bone Contraints, like the Stretch To constraint. This bone constraint stretches the bone along its Y-axis which lengthens or shortens the bone.
The object on the left in your screenshot is an Empty that is the Stretch To target. The thing on the right side is the armature with some bones and custom shapes. The muscle mesh in the middle is parented to one of the bones (XMSL_Muscle_bone.L) and this one has the Stretch To constraint (with a few others).
The magic bone (XMSL_Muscle_bone.L) is tiny and hidden in Object mode. Select the armature and switch to Edit mode and hide the big ones or uncheck Bone Properties > Viewport Display > [_] Hidden in Object mode.
Remove the bone constraint in Pose mode and the magic is gone ;-)

sure, I was faster, but you thought to try edit mode while I was confusing myself in pose mode.

I've noticed he use Stretch To etc, but I don't understand why the mesh doesn't have Armature modifier, nor vertex group. I thought they're needed for bone deformation?

Ok, I finally get it. It's not a "bone deformation" (like how we usually make animation), but a simple parenting relationship. It's just that simple, but somehow I forget you can parent an object to a single bone instead of the whole armature.

It does have an armature.  The shape on the right is a custom shape for an armature XMSL_Muscle SystemAmt specifically the bone XMSL_Muscle_flexor_bone.
The vendor of the add-on has gone to lengths to conceal what techniques they are using, but they are using a combination of drivers and constraints to maintain volume.  They are probably also using a hook to make the controller work in object mode.

Oh, you were faster :D


text:
Curve path doesn't work on outer edges
I created a 3d road. My problem is that I use curve path to bend the road,
but the path only bends the inner edges. How can I make it bend the whole mesh? I tried to follow videos to solve it, but all failed and my English is not that great. I used a translator. I hope some one can explain why this happens.

You don´t have enough divisions. You need to add more divisions in the road for it to bend properly


text:
How do I change the frame rate when working in 2d animation?
How do I change the frame rate when working in 2d animation?
I have a feeling there’s a simple solution to my problem.

What do you mean exactly with "change the fps 2d"?

change the frame rate in the 2d workspace... sorry i wasn’t clear! new to Blender

The framerate for all projects in blender is set in the Properties window >  Output > Dimensions > Frame Rate


text:
Rendered image is only a transparent screen
I was doing a roblox gfx, but when I rendered it, all I was seeing was a transparent screen, here is a screenshot:

Please read through the many causes of blank screens in the following links:  Render result is completely blank and Why does my object not show up

ok thank you so much i hope this works <3


text:
How do I apply sharpening via compositing to several movie clips simultaneously in my video editing project?
I’ve assembled a sequence of movie clips in Video Sequence Editor.  What’s the most efficient way of applying the same sharpening filter in composting to several clips at once?
Thank you

Afaik, there is no sharpening filter in Blender.
In general, if you need to add an effect filter to several strips, add an Adjustment Layer over all strips and add an effect to that.
For modifiers, there is a button in the sidebar/Strip Menu to copy the modifiers from the active strip to all selected strips.


text:
In many models, many objects have vanished and just appear as dots. Why?
My GPU is an Intel HD Graphics 530 - driver: i915 v: kernel.
on Linux Cinnamon.
A bunch of my models suddenly look very different in Blender. Some objects look unchanged, but most of the objects in any given model only show up as an orange dot at the object's center. In these cases the object itself is invisible, and yes they are all marked as visible and renderable.
Some models have dozens of objects and almost all of them have this useless behaviour. Closing and reopening Blender did not help. All the objects are meshes of simple shapes, combined with boolean operators (just about always Difference.)
I assumed I'd somehow corrupted Blender, so I deleted it and installed 2.91 (Linux). I opened models and the problem still exists. I can only assume there's some strange setting that's sticky across installations and models, but I'm still moderately new at Blender so I'm only guessing.
I have a lot of complicated models at this point that I do not want to lose. I don't want to try editing them (not that I could see what I was doing) for feat of doing more damage. Can someone walk me through fixing this?
This should look something like a vacuum tube (and used to):
Blend file: Something like a vaccuum tube

Can you please add images in the question to make it clearer

Intel HD Graphics 530 driver: i915 v: kernel

Oh, nevermind then. I'll try to get the question reopened. Never seen that one before...

try opening the files with a previous version of blender. Also consider sharing the file so that others can take a look at it.

Added URL for the blend file for the model shown above. It's very possible I clobbered some setting in Blender, but I don't see it. I tried this in the original 2.83.5 and in 2.91.0; no difference.

Opens fine on my end with 2.91.0 If you create a new file and append every object, is it still buggy ? Also side node, with version 2.91 you can add whole collections as booleans, so you just need the one modifier and group all your cutter objects into one collection. One object can be part of multiple collections too

I rebooted the system, and perhaps related, switched from Cinnamon's software rendering to hardware rendering in the reboot (but it's been set to software forever). The problem went away.


text:
Any Alt+S function not working
Any Alt+S function not working
Yesterday it was working just fine. Today I can't press Alt+S in blender at all.
The functions are bound to the shortcut but, when I press it, nothing happens. In the binding menu I can't even press the combination of Alt+S. Others, like Alt+G, work fine.
It's not my keyboard, I can press Alt S in other programs just fine.
Things I have tried:
Reinstall blender.
Restart pc.
New project.
Remove addons.
Factory reset blender
I honestly have no idea why this is happening.
Blender 2.83
Win 10

Are you using an English keyboard layout? Are there other languages or layouts active in your system? Clearly something changed in your OS since Yesterday. Did you do an update (or automatic update)? Can you roll it back?

Then you should try and change the function from Alt s to some other combination

I am using the right layout and I am sure of that. I would also like to know how to fix the issue and not to go around it.

Alt+S only and only works if your mouse is in the right window and if the blender window is active. like on paint mode in image editor or 3d view.
Other then that check to see if alt is not altered by any 3rd party programs. (like moving a window in linux)

I've also noticed  shortcuts not working. In my case, it was the shortcuts of "Sticky Notes" overriding Blender's shortcuts.
I removed all the Sticky Notes shortcuts (as I don't use it) and I regained all the shortcuts that were not working!


text:
blender symmetries are weird. It works strangely

When I made the chest, I mirror the ball on my body and used join.
The symmetries, which worked well in the face, became not the x-axis of object standards as shown in the picture.
What should I do?

If I am not mistaken, your object origin has moved. Try resetting it.

Enable "Affect Only Origins option" (see image)
Select your object in object mode and hit Alt+G to reset its transfrom

Or

Shift + C to reset cursor.
right click -> set origin -> to cursor


text:
How do I make cartographic maps with relief and color?
I am trying to make a cartographic map like this, I have the qgis software, base layers, and Dem available. What will be the workflow which I need to proceed to make maps like this?

Hello, the person shared their personal workflow in the link you provided : Use a height map to drive the displacement of a mesh, then texture it and add post-processing effects. Please share your attempts and where you are stuck, otherwise the question is too broad to even attempt to answer it fully

https://blender.meta.stackexchange.com/questions/2449/what-is-the-problem-with-posting-an-image-or-link-and-asking-how-do-i-do-this?r=SearchResults

For a beginner like me it would be really difficult to start without any pathway. If there is any respective discussions or tutorials available kindly share it with me.

Let me try the same and will get back to u.


text:
How do I make a map like this?
I just saw this river Basin map in Twitter and thought to replicate the work in another catchment I am having. I have all the associated files such as dem, drainage with me but I don't know the steps in blender.

https://blender.stackexchange.com/questions/67142/cycles-material-with-color-based-on-height-and-backside-in-different-colors/67145#67145 and https://blender.stackexchange.com/questions/5491/how-do-i-colour-a-3d-terrain-based-on-its-height and https://blender.stackexchange.com/questions/91648/is-there-another-way-to-make-a-coloured-topography/91653#91653

Thanks but first link is related but don't have any information related to the detailed hillshade and colour ramp used. Also nothing about the plane too.

The DEM you can use as height map. Then use the height to assign colors based on the height (detailed on the links on the second comment), the colors you use are up to you. If that doesn't help please [edit] your question and specify what kind of information you are in need of.

Ok. I will go through the links and test it on my own and update the question.


text:
When i bake the mesh on domain, i want to see the waters mesh NOT the shape of the domain mesh, how can i fix this?
So I want to color my fluids on the eevee engine and when I click "bake mesh" when having only the domain selected, instead of giving me a fluid mesh so i can chose the material for the liquid, instead the domain cube just kinda resizes to fit the liquid

You are using the tags for fluid simulation and ocean simulation, which one is it?

its kinda both, like its an ocean with a boat sinking and the boat spouts water


text:
How to set a lamp as camera?
I'm trying to set my lamp as camera, but every time I press Ctrl +0 it says: Modifier cannot be added to the object area.

Ctrl + 0 (or 1,2,3, and so) is to add a Subdivision Modifier, but Ctrl + Numpad 0 is to use an object as camera


text:
Accidentally deleted nodes in compositing tab. Can't recover it?
I accidentally deleted the 'Render Layer' and 'Composite' Node. I panicked and didn't know what to do, so I thought maybe if I close my file, itll come back when i open it again. So I closed my file, and obviously saved it because it had all my progress, but my dumb self didn't think through that it might save the action of deleted nodes as well.
I have tried everything to reverse this but nothing works. I tried manually adding these nodes. I do get the composite node fine, but the 'Render Layer' has missing bits.
I even uninstalled and re-installed Blender to fix this, but nothing.
I have attached images with the original 'Render Layer' node and the one I'm getting now (which doesn't have all the properties that I need).

Link: https://i.sstatic.net/Zmwdv.jpg
TLDR;
Accidentally deleted 'Render Layer' and 'Composite' Nodes. Can't recover them no matter what I do. Manually added nodes have missing properties.

please use the tools from this site to make images visible as part of the question.

Do not worry, this looks easy to fix, even if this diagnosis is wrong.
The image looks like render passes that were previously enabled have been turned off, and thus aren't showing up in the render layer node. Check this manual page for information on render passes. https://docs.blender.org/manual/en/dev/render/layers/passes.html

Thank you. I couldn't understand how to make sense of the info in the link you provided as Im still new to Blender.
But I figured out how to bring back these properties. Just had to turn on 'Denoising' under Passes in View Layer Properties tab. Thank you for pointing me in the right direction. :)

@AqsaN please write an answer detailing what you did so that other users with the same problem can learn from your experience.

Passes are kinda like raw ingredients that may have led to the ultimate product, AKA the output image, AKA the "Combined" render pass. Or sometimes they are just data that the render engine can "pick up while it's there" for you to use in compositing. Enabling other passes besides "Combined" adds extra available outputs to the Render Layers compositor node.


text:
Why has IK rotation constraint "envelope" stopped displaying?
Uptil yesterday,for the same Ik rig,  IK rotation constraint "envelopes"(red line) were being displayed.
However today,with multidimensional constraints they no longer show.
Is there an option to toggle them ON?

weird, could you please share your file?

Hi,blend file uploaded

In the N panel > Display, you need to activate the Relationship Lines option. In 2.8 it's in the Viewport Overlays panel:


text:
No change in Texture Paint Brush Sensitivity on changing Pressure Curves
In Blender2.79b/Windows10-64bit,stroke's painted with mouse,using the texDraw brush(Strength = 1,Blend = Mix ) on the default DiffuseColor layer(No Alpha) work fine .
However on switching to a pressure sensitive tablet(on latest drivers),the stroke is suddenly next to invisible.On changing the Pressure Curve  for the brush from the  Original [origin (0,0,)end(1,1)] to a New[origin (0,1),end(1,1)],the tablet stroke still remains next to invisible.
Normally, if the software recognises the MouseStroke it means the machine's hardware is able to compute the stroke realtime but when it does not detect the pressure sensitivity of the tablet ,it does mean that the machine is not able to compute and render the Pressure sensitive stroke realtime.
On disabling pressure sensitivity by changing the PressureCurve to a Flat (0,1)(1,1) this issue is normally solved.
However in this case ,the solution is not working.
Is there any other way to completely turnoff pressure sensitivity ?

In Blender2.79 ,Texture Paint has an "Accumulate" Option[Texture Paint Mode->Tools->texDraw brush-->Accumulate] which allows the TexDraw brush to daub strokes on top of the previous daub.This makes the brush daub thicker and hence visible.
However,this option is "OFF" by default. By toggling it "ON" the Accumulate featured is turned "On" and a visible brush stroke is rendered (also pressure sensitivity is supported) .

Priceless. I have never seen this before. Thanks.

Wasted an entire hour trying to figure out these options.It's great ,that  it worked.


text:
Display all values in a list as Text(Animation Nodes)
How to display 'All Values' in a floatlist as separate Text objects in 3D_Viewport?
TextObjectOutput accepts only single values

you can do it with this node setup:


text:
OpenGl 3.3 Error resurfaced with Blender 2.8 Final release
On my Windows10-64bit laptop (IntelHd 3000 Gpu - Opengl3.1 support) ,I was initially not able to run Blender 2.8 beta(zip) , but could run it on using this Opengl32.dll file found here
But now with 2.8 final version the Opengl error resurfaces , also when used with the above mentioned "Opengl32.dll "file .(All Gpu drivers are up to date).
Also, tried using this command line option but the error persists-
 .\blender.exe --debug -gpu

Any suggestion would be really help full.
Opengl3.3 Error

What is the error? Is there a message at all?

I have attached the command line error image (Opengl3.3 Error)

Blender 2.8 requires OpenGL 3.3 or above. Your computer does not meet the requirements and as such, Blender 2.8 will not run on it.
Using random DLLs from the internet is generally not a good idea, especially with programs as demanding as Blender.


text:
Link Object's property to Actions
Is it possible to enhance the animation(where all animations are instanced as unique Actions from the Nla Editor)  by changing the object's property (like material color etc)  whenever a particular action is instanced ?(eg.For a battle scene ,whenever a  slashing action is played the sword material color changes to "Red" .)

Sounds like a job for drivers.  If "ob" has the actions,  add a custom property  ob["slash"] Key in a value of say 1 in slash actions zero in others. Drive the material color with ob["slash"]


text:
BMesh object rotation
I create a BMesh from a list of vertices like that:
mesh = bpy.data.meshes.new(str(self.shape) + "_Mesh")
obj  = bpy.data.objects.new(str(self.shape) + "_Object", mesh)

bm = bmesh.new()
bm.from_mesh(mesh)

for v in self.shape.vertices:
    bm.verts.new(v)

bm.verts.index_update()
bm.faces.new(bm.verts)
bm.to_mesh(mesh)
bm.free()

It works, the mesh is created, but the rotation is set to 0,0,0.

Any idea how I can set the roation by the rotation of the first face for instance.
I know I can get the normal like this
bm.faces[0].normal

Best

https://blender.stackexchange.com/questions/19533/align-object-to-vector-using-python

See this answer for an explanation of how to determine the axis you want to rotate around. For example if you have two selected vertices, v1 and v2, this code will generate the necessary axis
axis = (v2.co - v1.co).normalized()

If you want to use the bounding box center of your mesh as the center of rotation you can use
from mathutils import Vector
center = sum((Vector(b) for b in object.bound_box), Vector())
center /= 8

replacing object with whatever object reference you are using.
The mechanism for rotating a bmesh around a standard axis is demonstrated by this code
from mathutils import Matrix, Vector
from math import radians
rotation_X = Matrix.Rotation(radians(45), 4, 'X')
bmesh.ops.rotate(bm, cent=center, matrix=rotation_X, verts=bm.verts)

Replace the quoted X with axis computed above to use an arbitrary axis.


text:
Motion tracked Video doesn't show up in the render or in the compositing tab
I tried to add a 3D object to a clip by following a youtube video. But clip doesn't show up in the render or in the compositing tab. It show up even in the camera view. I didn't change any settings.
please help.
Thank you.

And the  rendered images has only the cube in it like in the picture above.

What you are missing is the alpha channel on the render layers. Without an alpha channel the "alpha over" will fail. Enable Film>Transparent so that the areas with no geometry will be "transparent".

I did enable transparent and it still doesn't the clip. Background and foreground renders with transparent backgrounds and then only white backround.

It worked I just reconnected the render layer and it worked. thank you so much for the help.

I encountered the same challenge. However, marking it Transparent under Film under Render Properties made the motion tracked video clip show in render view.
That is, Render Properties > Film > Transparent turned ON.

I know this isn't a real answer but I also struggled really hard following cg geeks tutorial. i would feel sorry for people who try to do it. It just goes way too fast and he doesn't explain anything properly.It was very frustrating. However, I see you didn't set up the nodes properly. I did this same tutorial a few days ago and the result was quite successful. Maybe you can copy the nodes and change the images. Hope this saves a lot of time for you. Good Luck!
Link: https://blend-exchange.giantcowfilms.com/b/9a2z4LOy

Or press N and open the side menu in tracking panel...and go to track menu under footage and change focal length from 0 to any number..may be you have accidentally changed focal length to 0 ..if yes then it will solve your problem.


text:
How to optimize nodes and view layers created with motion tracking "set scene"
I have not used Blender in a long time but am working at learning some video applications for the software. what I have done is taken a sample video with a fair amount of camera motion and am learning how to add a model into the video scene. for now I am just experimenting with a still model working at simply adding it to the video , getting a shadow and having it track with the camera motion.
I would be interested in being pointed to some good up to date tutorials.
I could muster up more than a few questions if there is someone who knows a lot about this feature, I am getting some confusing results and find the documentation does not really say that much about the feature.
I don't know if that is normal, the file I start with has the model, rigging and a sun. prior to adding in the motion tracking the render is one pass. the compositor started with just rendered layers and composite.
this is what it looked like after solving the camera tracking and setting the tracking scene.

I thought it was the two versions of rendered layers causing the two pass rendering but even if I remove the second rendered layers and second alpha over the result I get is the same even though I have removed the rendered layer node that has no shadow.

Blender seems to insist on rendering that layer with no shadow first then as far as I can tell that is just discarded in favor of the layer with the shadow and because rendering is  time consuming I would rather cut that time then leave it doubled.
any help is appreciated.

https://blender.stackexchange.com/questions/108790/transparent-rendered-object-over-tracked-background/108876#108876

if you are happy with the results, then your setup works fine.

OK I figured out what is going on, the file started with one layer and when I used the camera motion tracking to set the background and tracking scene it created a new layer so Blender rendered both layers, the shadow catching plane was put in a background layer.

the simplified version on top does the same thing as the one with the extra layers , the camera tracking works all the same it just renders faster.


text:
What is the mathematical basis for F-Curves?
The Blender user's manual says:

Although F-curves are very similar to Bézier Curves, there are some important differences.

One of these differences is the fact that an F-curve doesn't allow a property to have more than one value at any given time. Blender's F-curves might take the keyframes and handles in the following image and produce the curve shown in the image:

However, a normal cubic Bézier curve with the same endpoints and handles would actually produce the following curve:

This curve contains a loop and is unsuitable as an F-curve.
So what is the mathematical basis for F-curves? More importantly, can you direct me to any scholarly articles that describe this type of modified Bézier curve? (or at least some good search terms for me to research)

If blender didnt use the F-curve method, to draw "f-curves" like Justin mentioned, then how it is draws the curve in the graph editor correctly (if it is correct) with the given handles in the first place? Its possible that the f-curve method is correctly implemented in the graph editor ui, but not in blender?

After some digging through the Blender source code, I found the answer.
Short answer: They're just Bézier curves.
Long answer: They're normal Bézier curves with certain restrictions placed on the positions of the handles (the red circles). If the first handle is to the left of the second handle, as in the following image, then the curve is evaluated as a normal Bézier curve:

This guarantees that the curve will not turn back on itself.
However, if the handles cross (the first handle is to the right of the second handle), their positions need to be adjusted to avoid loops. The file fcurve.c (blender-2.77a\source\blender\blenkernel\intern\fcurve.c) gives the answer on line 2199:
/* adjust handles so that they don't overlap (forming a loop) */
correct_bezpart(v1, v2, v3, v4);

On line 1830, the correct_bezpart() function begins. The function finds the width of each handle and the width between the two keyframes. If the combined width of the two handles is greater than the width between the two keyframes, then the two handles are scaled down so that they don't cross each other, but their relative lengths are preserved. The original handles are used for drawing to the graph editor, but the scaled down versions are used for generating the curve, a plain-old cubic Bézier curve.
Here's an example F-Curve before correction. These handles are not used to create the actual curve; they're just drawn to the screen in Blender's graph editor:

Here's the same curve, but with corrected handles. These handles are not seen in the graph editor, but are the ones actually used to create the curve. If you want to pull out your ruler, you'll see that neither the lengths of each handle relative to each other, nor the angle of the handles were changed.

If you're not convinced, I invite you to look at fcurve.c and see for yourself. Overlapping handles are detected on lines 2188-2190. The actual handle correction takes place on lines 1830-1866.
As far as why they're called "F-Curves", your guess is as good as mine. My guess is that the 'F' stands for 'function', meaning that, like a math function, each x-value maps to exactly one y-value (A Bézier curve is indeed a function, except that an (x, y) pair is a function of t).
Whether this method is the brainchild of Blender developers or was the result of some third party is still a mystery to me. The answer to that question, in my opinion, is more valuable than the method itself.

It's right under your nose ;-) They are a member of the "Bezier Spline" family called an "F-curve," shortened from "Ferguson's Parametric Cubic Curves."
The F-curve is actually a direct derivative of the Catmull-Rom Spline (names you should recognize from other CGI algorithms). As stated in the introductory research an f-curve:

"attempts to fix the tangents at certain control points to be the average of the slopes of the two line segments of the control polygon adjacent to each control point. The matrix equation is then just a simple result of matrix algebra."

So, an f-curve is specifically designed to be simple, an average, and to have only one solution for any given point.
The Blender Manual says:

Although F-curves are very similar to Bezier Curves, there are some important differences.

This paper describes them in the context of CAD and CGI:
http://www2.mat.dtu.dk/people/J.Gravesen/cagd/cagd.pdf
...but it surprises me that I can't find anywhere that 'Ferguson Curves' are called 'f-curves,' though that seems the most likely case.

Maybe I'm missing something, but where in that paper does it say that the curve will only have one solution for any given point?

@Justin It maps the control points to a cubic polynomial function  https://en.wikipedia.org/wiki/Function_%28mathematics%29

It's quite possible for Catmull-Rom splines to have loops (see figure 2(b) in this paper for instance). In any case, animation curves allow the user to edit the tangents, so they aren't Catmull-Rom splines in general.

@NathanReed I thought that was the difference between Catmull-Rom Splines and F-Curves?

Well, the bit you quoted explicitly says the tangents are not editable, since they're fixed based on the locations of adjoining control points. That's exactly the definition of a Catmull-Rom spline. I'm unable to tell from the page you linked if there is any difference between "Ferguson splines" and Catmull-Rom splines; the text seems to use the names interchangeably. In any case I doubt if the term "F-curve" has anything at all to do with "Ferguson splines", unless you have a source that says so? IMO it's more likely F stands for frame, as in keyframing.

I must have misunderstood that part about the tangents. I'll add some sources.

....it's also possible that "f-curve" is just the Blender shortening of "Ferguson Curve," and no one else actually calls them that

In 3D animation tools I've used, the key difference is that animation curves as shown in the graph editor are not actually 2D Bézier splines. They're 1D splines, parameterized by time (plotted along the X axis in the graph editor).
When you use splines to create curves in 2D or 3D, the spline has a parameter t that runs from 0 to 1 along its length, and the curve's XY or XYZ position is a function of t. This allows the spline to be oriented in any direction, and it can form loops because there is nothing preventing the curve from turning around and going "backward" in XY space as t increases.
With animation curves, t is (proportional to) time, and whatever channel is being keyed is a function of t. When you see the curves in the graph editor, they are not being rendered as 2D splines with XY being functions of t; instead, the value of t is based on the X axis position (corresponding to time), and the Y position is the output of the spline at that parameter value. So, animation channels are effectively 1D splines, graphed in the standard high-school algebra way, with Y as a function of X.
That explains why you can't make them loop "back in time": it's because time is an input to the spline and not an output. Compare this to 2D splines, where XY are both outputs, and the input parameter isn't being explicitly graphed.
Also note that you can easily animate an object to move along a looping spline such as the one you showed in your example, but when you view its curves in the graph editor, you'll see no loops there!

What do you mean when you say "t is (proportional to) time"?

@Justin I mean animation is done by increasing the value of t from 0 to 1 over a period of time.

Sorry to be so nit-picky, but t (the input to the Bézier function) is not exactly proportional to time. Depending on the shape of the curve's control polygon, the parameterization of t could be squashed to one side of the curve or the other. You actually have to do some root finding to find the t value that corresponds to the desired time value.

@Justin Hmm. If you've looked at the source, I believe you, but that seems very strange to me. AFAIK, in 3D animation tools splines are usually directly parameterized by time, so adjusting the parameterization allows you to control the speed the object moves. I'm not sure what is gained by having time be decoupled from the parameterization.

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


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What is the range of values produced by Cycles texture nodes?
When I create a Cycles shader, I often take the 'Fac' output from a Texture node and feed it to the 'Fac' input on a Mix Shader. I'd like to know the exact range of values that this output produces so that I can transform it with Math nodes and not have clipped values.
Is there any documentation on the range of values that each of these texture nodes produce?

It ranges from 0 to 1, 0 representing black and 1 representing white.

I am not sure this is perfectly correct: The Cycles Noise texture seems to have a range of [a, b] where a > 0 and b < 1. You can plug the ouput of the texture into the background with strength 1 on an empty scene, and render it out, and analize the values of the resulted image.

By plugging the the output to a math node, I have seen the musgrave texture output values from -1.3 to 1.4.

If you want to ensure the values are between 0 and 1 there's a "clamp" checkbox in the math node.

@Steve That would work, but if the range is substantially larger than [0, 1], you'll end up with clipping artifacts. I'd rather know the range, then remap it to [0, 1] so I lose less information.

Rather than list the specific ranges of the texture nodes it is more useful to provide the tools you can use to analyse them yourself - partly so that you could apply the same technique to any other texture or shader function you made create in future, but also because stating specific upper and lower ranges is meaningless unless you also appreciate how the values are distributed over that range.
For example, consider a mathematical 'normal' distribution (https://en.wikipedia.org/wiki/Normal_distribution) :

In a normal distribution, the values are centred around a specific place - there is more chance than any particular sample will be near that centre and progressively less chance the further away from the centre you go. However, where does it end? Technically the range is actually -infinity to infinity as there is a chance of any value being returned by the normal function - just progressively less chance, the further from the centre you move. How could you measure such a boundary?
From a practical point of view, however, we may just that we've reached the limit whenever the chance of a result of a certain value is below a particular threshold. ie, it becomes very relevant to know the shape of the distribution to be able to determine where the practical limits are.
The built-in Blender UV/Image Editor window includes tools that can show the distribution of values and we can use that to analyse the output from any node. Open a UV/Image Editor window and press T to open the tools panel. You should see a Scopes panel with a number of graphs. The most useful for this situation is the Histogram panel :

The histogram shows an analysis of the pixels in the image over the range 0.0 to 1.0 for each channel R, G, B, A in addition to 'combined' channels Luma and RGB, with the shape of the graph showing how those values are distributed throughout the image. The peak shows what the most common value is, the lower the occurrance, the lower that point in the graph.
The histogram shows the analysis of the image after any color management has taken place on the image. Therefore, to avoid skewing the results we need to first disable color management. This can be achieved by opening the Scene properties and selecting 'None' in the Display Device setting of the Color Management properties.

Since the histogram only shows values in the range 0.0 to 1.0 and some of our textures (such as Musgrave) produce values outside that range, we'll need to apply some maths to shift and scale the values to something more useful. Since the Histogram window includes grid lines to split the graph into 4 we can use the centre line as 'zero' with a range of -2.0 to +2.0 using the following nodes :

Note that this shows the nodes for the Environment rather than a specific material. By removing all the objects from the scene and simply rendering the environment we can get a clean image that only contains the results of the texture being tested.
Now simply plugging different texture's Fac output into the Color input of the Background node and pressing F12 to render should produce an analysis of the texture as a histogram. For example, Noise produces the following :

Note : Varying the Scale of the texture node will affect the smoothness of the curve.
For the Noise example above the vertical grid line in the centre of the histogram represents 0.0. Values to the left of this are increasingly negative (with the 1/4 grid line representing -1.0) to the left-hand edge, representing values of -2.0. Similarly, the 3/4 vertical grid line represents 1.0 while the right-hand edge represents 2.0. As can be seen from the graph, the values of the Noise texture centre around 0.5 and vary down to about 0.25 and up to about 0.75. However, there is a 'tail' that theoretically extends indefinitely - presumably down to 0.0 and up to 1.0 but with ever decreasing frequency. So, for practical purposes the Noise texture varies from 0.25 to 0.75 with approximately a normal distribution.
Plugging other textures produces the following :
Voronoi - varies between 0.0 and 1.0, biassed towards the lower end and gradually dropping off :

Musgrave - centred around 0.0 and tailing off to -1.5 and +1.5 :

Magic (Fac) - between 0.0 and 1.0 with a high peak at about 0.3 :

Wave - Between 0.0 and 1.0 with more values at either end (the peak and trough of the wave) :

Similar methods can be used to analyse the Color output of the textures by splitting the color into individual channels and performing the same calculations before combining back into a single color. The histogram can then be used to split the channels to compare :


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Cycles: Assign material to vertex group
I know it's possible to have multiple shaders for one object with the internal renderer. This video explains the process.
Can I use Cycles to assign a material to a vertex group so that a single object may have multiple materials? If so, how?

Related: http://blender.stackexchange.com/q/516/599

Yes. It works exactly the same, just press the "Assign" button with the desired vertex-groups/faces selected. Unassigned geometry uses the default (first) material slot.


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Override final pixel color in a Cycles/OSL shader?
In the Renderman Shading Language, the whole purpose of a shader is to determine the final pixel color for each fragment. You have complete control over what the shader does and what the final color is. If you have a scene with a mountain covered in snow, with trees in the foreground and a lake, if you want the whole image to be completely red--like (255, 0, 0) red in every single pixel--you can do that by setting the final color at the end of each shader. It can completely disregard the lights, image textures and geometry.
Is this possible in Cycles or OSL? I realize that the REYES algorithm is a very different beast than OSL closures in a unidirectional path tracer. But, can I override the physically-based-ness of Cycles in a shader?

You're right. Not sure why that question didn't show up in my searches.

I do believe that RSL scripts might have more control over the final colour than OSL scripts do. From the OSL specification --

A closure is an expression or function call that will be stored, along with necessary contextual information, to be evaluated at a later time.

What this means is the green node sockets that connect to the Material Output provide the render engine with a way to calculate the final colour not the specific colour to use in the final image. The steps of mixing reflections and lighting is performed by the renderer not by the OSL script.
For interest the first example that gandalf3 pointed you to can be achieved in OSL with --
shader flatcolour(color Colour = 0.8,
    float Strength = 1.0,
    output closure color BSDF = 0 )
{
    if(raytype("camera"))
        BSDF = (Strength * Colour) * emission();
    else
        BSDF = transparent();
}

This script didn't work for me. The model always comes out black, no matter what color I set it to.

Did you turn on OSL in the render properties?

Of course not! That would be too simple. ;)


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Rigid body initial velocity/rotation?
Is there a way to specify a rigid body's initial velocity or rotation?

An initial velocity in what? The game engine? The particle system? One of the simulations? Can you add more information to your question? Most questions should be about a paragraph or two long.

Do you mean angular velocity instead of rotation? Because the initial rotation is the one you set in object mode.

Sorry, I should have specified. Let's say I have a cube I want to have shoot sideways at 3 m/s and rotating on its z-axis at 10 degrees per second. Once the simulation starts, it will move sideways and rotate, but also downward because gravity is affecting it.


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Command line error
I'm trying to run Blender from the command line but I'm getting the following results. Obviously, it didn't render. It worked for me with Blender 2.68, but quit as soon as I put 2.69 on the computer. I navigated to the folder where blender.exe is found, and still couldn't get it to work.
./blender -b ../CSANM454/blender_tests/caustics_test.blend --engine CYCLES -F PNG -x 1 -o //theFrame
Read new prefs: /users/ugrad/[my username]/.config/blender/2.70/config/userpref.blend
found bundled python: /users/ugrad/[my username]/blender-2.70-linux-glibc211-x86_64/2.70/python
read blend: /users/ugrad/[my username]/blender-2.70-linux-glibc211-x86_64/../CSANM454/blender_tests/caustics_test.blend

Blender quit

I'm trying to run this command through PuTTY. Any idea why it will no longer work?

Whats the error? - you aren't passing a command to render and its not rendering. What do you expect it to do?

Looks like I need to add the -f option. Thanks for the tip


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Pointy meshes pierce cloth sim. How can I get around this while also keeping the physical qualities of my cloth (e.g. mass, stiffness, etc.)?
Pointy meshes pierce cloth sim. How can I get around this while also keeping the physical qualities of my cloth (e.g. mass, stiffness, etc.)?
Here is a simple example of the problem I'm having:

I've already tried increasing the collision quality, the distance, and the repel distance, but to no avail.
[ADDENDUM] I've found that an increase in collision quality can fix this (at least in 2.8--they may have adjusted things since 2.79). The only thing is, you can't just up it a few notches (which is why I previously didn't see benefit from it), you need to crank that number--enough that render time can become ridiculous but if it works it works.

You could try using face collision, but that slows things down allot... Serge’s answer seems to be a good solution to the problem.

@BigfootBlondy Render time isn't a big concern. What is face collision and how do I use it? I can't find anything in the blender manual on it.

Apologies, I only had my phone last night. Face collision is only available on soft bodies. I will post an answer shortly

As far as I can see, there are two issues causing this problem.
Keep in mind I am using an early 2015 MacBook air to do this so I cannot go to as high samples as you or others reading this can.

Blender calculates most of its collisions through vertices. As they come within close proximity of one another, it slows the vertices velocity. If it is moving fast or there are more vertices pulling it down (As in your mesh), blender has a tenancy to let the vertex pass. So to fix this we need to increase the number of collision vertices. This also can be done using two changes. One is to up the number subdivisions of the cloth mesh and the other method is to up the number of vertices of the point.

Subdividing the mesh is simple enough. Hit subdivide. But to get performance, you may need to select the area close to the point and subdivide that a lot, as I have done in my image below.
Adding more vertices on the point. This can be done by adding a sphere or icosphere to the point of the object. This needs to be small enough that it won't be noticeable from the distance you are rendering at. If it is far, it can be quite large, if it is close, you will need to make it smaller. I have made an example, though it is of low resolution, it still fixes the problem. If you don't want the ball in the render, turn it off in the Outliner window.

The quality steps and collision steps. They will only do so much to the quality of your simulation, but it does help. In my final output, I set my quality steps to 25 and collision steps to 5. The one that made the most difference was the quality, but I think both should be increased.

Here is my result:

Remember, this is on a low power laptop. It took around 1 min to produce the first 58 frames. Yours may be at the same by the time you up the quality. In my render, you can see the change in mesh in the final result between High subdivisions and low subdivisions. If you want to minimise that effect, subdivide on an ever-shrinking area so it fades into the higher quality point of contact.
Hope I helped and best of luck with your project,
BFB

I suppose this means if I wanted to make a "low poly" cloth, I would have to find a way of "locking" the vertices of the area together to give it the appearance of a single larger face. Any idea of how I could go about that? Also, in a "gaming" context, where the exact area of collision is not certain, would you just have to use a ridiculously high amount of verts?

If you wanted to make a low poly cloth, do this then either remedy it or decimate it. And in a gaming context that is different. Game engines usually handle collisions differently. I am not sure about blenders engine but I know unity does it differently. A high number of verts is a bad idea in games

Sorry, in my above comment I am referring to the remesh modifier and decimate modifier. Was a little unclear with 'remedy' ;p

Is there no other way that Blender is able to handle collisions like such game engines, for when the need/purpose is there?

To be honest. I wouldn’t know. I would have to leave that up to someone else as I do not use the game engine. If you want it asked, I recommend creating a new question if you cannot find the answer elsewhere. Just remember to tag it as a game simulation. Just please remember to mark this as solved if your question has been answered so others with the same issues can see that there are successful answered here. Thanks

Nice answer. It would be nice to include an alternative method using Soft Body face collision as mentioned in your comment to the original question - have you tried that? Does it work? Personally, I prefer soft body to cloth as it tends to be more configurable and versatile.

@Rich Sedman I tried soft body but I found it didn’t collide correctly. The collision on the point was worsened. And because I am on a low power computer, when I tuned on face collisions my blender froze with the good old spinning wheel of death. The performance drop was way to much for me to even mention the method. But you could try it. I don’t see why it wouldn’t work. Just cpu intensive, that’s all. The upside would be you could create effects such as balloon/balloon popping in one object. As you said, more versatile, but quite performance intensive.

@BigfootBlondy I've given this a try using Soft Body and Face collision with some success - but not complete success (did still get some of the spike protruding) and with way more processing overhead than your suggested method. I think the solver steps would have to be unfeasibly large to prevent the point from poking through (and having such a large number of steps brings its own issues of rounding). My vote is most definitely with your answer.

Thank you @RichSedman for trying the soft body method. Makes it difficult for me to help people with the limitations I have :)

Use Pin option

Create vertex group for single vertex of cloth, where you expect
spike to collide (it is Hook in my example)
Parent Empty to Spike object and relocate it at the peak. This will be a hook object to deform Cloth with respect to sharp Spike
Add Vertex Weight Mix, Hook modifiers before Cloth sim
By animating influence slider you can control both pinning and
hooking. In this case value of 1 will clear vertex group and release
physics simulation, while 0 doing the opposite.
Influence should be keyframed right before Spike is going to
collide Cloth

This solution does work, but I have two big problems with it. Firstly, the cloth doesn't fall on the object and fit its form, it just sort of hovers around it like an umbrella. Secondly, I would much prefer a method where I don't have to specify where the collision is about to happen. Something I can apply across the entire thing so that any collision between the cloth and spike will not cause the meshes to overlap.


text:
Is there a way of 'cooling' smoke over time?
I want to make my smoke simulation send smoke up, but eventually that smoke begins to fall, simulating the smoke losing thermal energy over the period of time it exists. How can I go about this in Blender and, ideally, is there a way of editing a curve of the derivative of temperature to time, so that I can control how it cools?
The only thing is, I don't think it would be as simple as editing a dope sheet, since I want the smoke to continuously do this. As in, the smoke immediately coming from the emitter is warm throughout the timeline, while the bits smoke that have lasted a few seconds get colder. I think directly using the temperature in a dope sheet would just cause the emitter to change the temperature of the smoke immediately coming out of the emitter while also having that smoke remain at the same temperature throughout the timeline, which is not what I want.

In the current blender smoke system, it is not possible to add a time-dependent temperature gradient (thermal energy loss). 1) However, if you use a negative value for temperature difference (in the domain) that will allow smoke to settle down (fall downward) on an obstacle object or domain bottom. Then using dissolve option (in the domain) and a wind force to achieve something like you ask in the question. 2) The second way is to use particles. Because you can damp the velocity of the particles over a period of time so that they settle on a floor and use these particles as the smoke emitter.

@3DSinghVFX Yeah, I was hoping for smoke that would rise because of the heat then slowly fall. I imagine I program the behaviour into a particle system though.

If you want the smoke to rise for small time period and then fall down or settle down, I think it is possible with smoke system and wind force.


text:
How can I create a soft, fluid filled pod that can rupture?
I was watching a trailer for an animated short film and there was a moment when a green pod split open and a person fell out, along with a bunch of fluid. I've set up the link so it begins on the exact part I'm talking about. (Edit) I've also made gifs of the scenes featuring it, as best I can. Also, I use Blender 2.8 and while I'm sure I could find the equivalent settings to the 2.79 ones after a ton searching, I'd prefer it if an answer were written for 2.8.

I really like this effect and I want to recreate this animation; my best guess is use a fluid sim with a soft body sim but I have no clue how; I'm pretty inexperienced with sims.

Well, you are expecting a full blown tutorial here. I don't think it's gonna happen. In the meantime you can find answers/tutorials that will help you create what you need. Soft Body (bake) > Fracture modifier > Fluid (high viscosity). Too many topics to create one sane answer with your "expectations". Try maybe to part this question for: How to make soft body pod? How to fracture pod? How to make dense fluid?

@cgslav Sorry, I should have explained my expectations better; that's on me. What I mean by clear and concise instructions isn't me asking for a step by step tutorial of every single component. The stuff like 'how to make a soft body fracture' or 'how to make a viscous fluid' is stuff that is most likely already answered and I can easily find by searching stack exchange or the answer could reference those other questions with links. The 'step by step tutorial' that I'm looking is on how to pull it all together as one project and make all the simulations/modifiers interact properly.

What part of this are you currently struggling with? How far have you got? It seems that you're expecting someone to produce you a fully formed solution to the whole thing - specific to your particular need. Split your problem into the individual elements, give it a try yourself and if (when?) you get stuck, then post a specific question about overcoming that particular hurdle. This will produce questions that are more manageable as well as being more applicable to other people's problems, making any answer far more valuable to the community. As it stands I think this question is off topic.

@RichSedman Fair enough, I'll concede to that point. Little disappointing that I wasted a bunch of rep on this though, but 'eh, so be it. Anyways, I'm not entirely sure if it would be appropriate to delete this post because of those reasons or if I should request someone with the required privileges to close it, since SE generally seems to discourage users from deleting material.

Don't worry about the rep - all is not lost - and don't delete. You could edit your question to narrow it down to one specific part of your problem while still referencing the overall goal. You can add multiple questions, one for each step along the way to the final goal. If you manage to solve any of the problems yourself, add your own answer and you'll gain reputation for any upvotes on your questions and answers. The narrower questions will be more applicable to other people's situations and you're much more likely to get results.

I would say make a hollow softbody (I guess with the boolean), make it breakable (how do I make an object bend or break if hit with sufficient force? - see the bottom of the first answer), then add fluid inside (https://www.youtube.com/watch?v=1gM8yEMFMjg). I'm not that experienced with those, but I'll do some experimenting and get back to you if i get anything useful.


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How can I get values based on the thickness of an object relative to the camera?
I'm trying to make a material that resembles some kind of liquid; it is opaque where it is thick and transparent where it is thin. I'm planning on mixing a diffuse and glass shader with presumably a custom node (if one doesn't already exist) as Fac.

The diagram above illustrates what I need, showing a camera and a single object (with two physical parts).
I need a node that will give me back a 0 to 1 (ie. black to white) value depending on the distance the camera's rays must travel through the object (the purple lines in my diagram).
Because it wouldn't make much sense for the 'perceived thickness' to simply be the first purple line segment on a ray. It would probably be best if the length of the purple line is the sum of the segments of it on that ray in the object, even if part of the object is physically disconnected from the other parts.
I've look around but I can't find much of anything that seems to fit the bill for what I'm looking for. I was hoping someone has already written a node like this or if there is a node setup I could use.
P.S. I use 2.8, so some older scripts might not work for me.

@cegaton I've already tried volumes; they aren't an option for me. Volume absorption won't show a white volume. As for volume scatter, the volumes come out dark when a glass shader is also used. I've read link but regardless of how high I set the volume bounces, it still stays fairly dark.


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I can't get openimage denoise to work on linux
I saw this questions asked already, but the way they explained the solution made no sense.
I only got linux two days ago, can someone please tell me step by step how to get it working.

Where did you get the build you are using? Is it self compiled? It does not appear to have openimage denoise enabled from the image you have posted. Not all of blenders configuration options are mandatory for building.

How did you install blender? Can you point to the link for the other question?


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Smoke looks blurry even though resolution is set to a high value
As you can see, smoke looks very blurry.
I have tried everything people said on other forum, but since the way blender simulates smoke has recently changed, most of it isn't helpful.

This was with 200 resolutions division and 3 upres factor. Most tutorials I watched used these setting or slightly more or less, yet they got noticeably better results, whether in viewport or rendering.
I don't see what I can do to up the quality, the edges are fuzzy and the whole picture is overall blurry.
Any help would be appreciated
Edit : this is with denoising  :

better, but still nowhere close to the cool high definition renders

Try significantly increasing Max Steps in the Volumes render properties and/or decrease the 'Step Rate' for render and/or viewport.

I don't know what tutorials you are watching, but that looks pretty comparable to what I've experienced with ~200 resolution divisions. The upres factor will not improve the appearance as much as increasing the resolution value.

Number of Divisions has nothing to do with "blurry" result. More divisions gives more details (volume grid is detailed). You can try to sharpen with ...
Default 32 Divisions

add Math node Multiply 100 into Density socket

add node Color Ramp

to get rid of lines change Render Properties > Volumes > Step Rate 0.1

(Step Rate - lower value means less "lines" in a volume.)
Play with ColorRamp to get more or less of volume ...

This worked like a charm ! Thanks, I didn't expect this !


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Im unable to scroll in Blender
For the past few days, I'm trying to find how to get my scrolling back
when I try to do work It's just doesn't scroll down or up (the white blank page)
It's annoying me and if anyone knows how to bring it back?
I even reset to open the default settings file but it doesn't work

Is it your first time in blender ,  you move around by holding the middle mouse button. Moreover , if you want to zoom in and out you can scroll you middle mouse button and it wonk work if you are in middle of drawing something like a line or a curve , confirm the draw by middle mouse button click or ENTER.

But  i dont want to use mouse . I can zoom in but ...  im unable to scroll .This is in my laptop so i need to use scroller every time i zoom in i have to touch the scroll using my touch pad.... so .... If u know any short root  to scroll using just keyboard? Or something

im really not aware about what you are asking but even im on laptop and i also have a mouse , but do you want to scroll down and up , theres no need of doing that

Im really sorry ab this ....... i used blender like literally after 1 month n i forgot i used to use the hand (move the view) in right of the screenshot.... above the toggle view .... I immediately rushed here to comment thiss  after i remembered


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What to do when my animation stops after 50 seconds, whereas my animation player is in active?
I had an idea to make fire effects on a cube. So I created a cube; clicked F3 and activated quick smoke effect.
Then my cube started smoking.
But unfortunately it sopped after 50 seconds.
But I noticed that my animation player is in active mode.
After,when the animation player replayed the smoke effect ran only for 50 seconds and stopped again.
I also tried for quick liquid, but the result was the same.

Check under physic settings > fluid > cache, the Frame End properties.
250 frames / 25 fps = 10 seconds of animation (50 seconds seems a little out of default blender settings).


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How can i get rid of many vertices?
How can i get rid of so many points? I applied bevel modifier to round the edges of a plane.

Select all and Delete (X) > Disolve Limited ?

or Alt M > Merge By Distance?

You can select all your vertices, go in the header menu > Select > Checker Deselect:

Then you can change the options in the Operator box, and delete with X > Dissolve Vertices:

https://imgur.com/3zGgvAE

doesen t work i tried

what's happening exactly? I can't see any reason why it would not work, please retry

Nothing happen when i select these and i prex x and disolve vertices

so Checker Deselect works?

yes i can select with it but i can t delete

please share your file: https://blend-exchange.giantcowfilms.com/


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Error, too many subdivision?
I am trying to render a still image with a well known Render Farm service. When I upload my file it returns the error: 'Project uses to much memory while rendering. Please check for too many subdivisions.' Trying to render also crashes my machine for presumably the same reason.
Can someone please help me to understand this error and how to fix it?
My file has 2.9m verts. It is composed of a dozen or so arrays which use a set of base objects to generate their iterations. Each of these have solidify and subdivision surface modifiers.
Do I need to reduce the number of polygons? It doesn't seem like that many too me.
To do this can I apply the solidify and subsurf modifiers to all objects, and then decimate geometry? Or is there another way to get the memory usage down for rendering?
Sincere thanks if you can help, happy to upload the .blend just ask in comments please if it will help to see it.

What about textures? Are you using hi-res textures such as 2k or 4k (or more)? They could be hogging video memory.

No I don't think so, there are only two base objects, one uses a 154kb png file with bump map and shaders, the other objects' textures are all built with shaders: and include transparency, bump map and, subsurface scattering

Hmm. I don't know then. Is there somewhere where the render farm posts a list of written "limits"? 2.9M verts is a lot, but certainly not unmanageable. Maybe your file is fine, it's just breaking their "rules" so to speak. It's possible that calculating the subdivision influence is what's jamming the memory. Try applying the modifiers first.

Is 2.9 mln verts the result of modifiers or are they added on top of objects which already have that amount of geometry? Other than that maybe the problem is indeed somewhere else and not in amount of geometry

The 2.9m verts value is from the lower right on the Blender interface, so I'm assuming that's before the modifiers are applied in the render. They have not been applied in the materials tab, they are stacked. So that could be the problem... I'll test using 'Simplify' under Render properties tab, and a few other tests to see if I can get it to render.

I reduced the resolution to 1920 from 2688 (which is high I think?) and I limited the Subdivs to 2 using Simplify in the Render properties, and it rendereed in about 1 min on my non GPU machine, it looks like that is the issue, need to limit the subdivision numbers on all of the arrays... (they were all set at 5 for Render)

Read this link: https://blender.stackexchange.com/questions/28222/blender-render-crash-when-using-subsurf-modifiers

many times solidify essentially doubles the geometry. without any clue what the geo looks like, i would first ask if its needed. or use dupliverts, or particle instancing instead of arrays to reduce memory use.


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Why is smoke getting caught my container
I tried to set up a thing where smoke (being emitted by a small circle) was coming out of cylinder that I inserted and extruded to make a cup. For some reason, the smoke would not rise until I moved the circle past the opening of the cup.

[EDIT] I've recreated the file in 2.8. Even when I bake it, the problem remains.

Can we see a screenshot of the domain settings? make sure your cylinder isnt set to collision. But we really dont have enough info with what you provided. Make sure you baked it, make sure you have the density high enough, Make sure the normal of your small circle is not facing the wrong way. Could be many things.

I stuck with all the default settings of 2.79b. The cylinder is set to collision, because I thought that was what I wanted for an object to physically interact with the smoke. I have not baked it yet.


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blender 2.80 - particle system makes object not renderable
in my scene I have a problem with my tree object. Whenever I apply a particle system to it, it's not rendered anymore. You can download the file here:

Has someone an idea, what's going on here?
Any tip is appreciated and thanks in advance!

In particle settings -> Render -> ON the option  "Show Emitter", that allows Blender to render also the base object (particle emitter).

Thank you very much! I never realized that option.