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Using view-camera-set active object as camera is zooming in to the object as i am new can someone explain why its hapening
Using view-camera-set active object as camera is zooming in to the object as i am new can someone explain why its happening. Kindly  check this video.

Hello and welcome. Please provide some context and explanation by verbally describing your issue, don't just post, images, videos, files to download, or links to external sites. See What is the problem with posting an image or link and asking “How do I do this?”

You are choosing Set Active Object as Camera from the menu. When you have no active object currently selected, this refers automatically to the last active object (unless it is deleted).
The last active object in your case was the "Icosphere", this is indicated by showing the name in the top left of the 3D Viewport and highlighting the object symbol in the Outliner. When you set the icosphere as camera, your view jumps to the origin of it, which is in the center of the mesh.

Hi ,Thank you for clearing my doubt may i know the exact use for this option as u are well experienced it will be helpful and while searching youtube abou this issue i found that by going to view - Local camera- camera the problem was solved .But i dont know what it is used for though thanks you.

First of all if you would have selected a camera as last active object, you could have switched to that camera which I guess was what you wanted to do originally. The other thing is, for example you have a character in your scene and you want the camera to be placed where his head is. You can then either place a camera on the head and parent it to the head, or you can simply make the head the camera. In this case you can either disable camera visibility for the head object so that it does not block the view from inside or set the clipping start to be in front of the head to make it disappear.

However, the camera view is always pointing in object's -Z direction, so this is probably not very practical in many cases. If you cannot imagine a use case for this function, it does not matter, then it's simply not made for you. There are other things in Blender which I don't use, but others might.

Thanks understood


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How to select all the vertices i can select only the vertices visible in the camera view
Hi i am trying o select all the vertices but unable to select all when used drag to select but i can choose all in the wire frame mode  i found  Limit selection to visible can be used to select the vertices without going to wire frame mode but how to enable it .Thanks in Adv.

You can probably select the rest by hovering over one of the verts and hitting 'L'. Just Box selecting in Solid view will select only the visible vertices as you've found.

@JohnEason Looks a bit like as if the object was one connected mesh. Hitting L will then simply select everything, not just the lower part.

@GordonBrinkmann True. That's why I said "probably". Difficult to say without seeing the Blend file.

Enable X-Ray mode in order to select occluded areas (Shortcut Alt Z).

source: Stack Exchange

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

sort: votes


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How to rotate or pan in the view port while performing scale or rotate actions
I am new to blender so im trying to check other angle when i tried to scale a face but i can only do that after conforming the action so is there a way to check the results of scale or rotation and even moving without applying it first .

The option will be available in version 4.0. From Release Notes: "It is now possible to navigate while transform (Move, Rotate, Scale, Edge Slide, Vert Slide, and Shrink/Fatten)" - https://wiki.blender.org/wiki/Reference/Release_Notes/4.0/Modeling

Although you can perform an operation in only one view, you could always pop in a quick split with a right-click on the frame of a region, and view it from different directions..

Thats great thanks

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


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Using KEYMAP to set wireframe mode one object alone
I am using blender 3.6 and i want to use key to view wireframe of only one object alone and i saw a page were an author explains it but as im new i dont know how to do it can someone help me with a step by step guide .https://blenderartists.org/t/shortcut-for-selected-objects-in-wireframe-mode/1357808/3   (LINK TO THE ARTICEL) Thanks.

There's no need to go into the keymap settings to set a shortcut for that option although you will need to save the preferences to make it permanent (see below). Select an object and go to the Object Properties tab on the R/H sidebar. Open the Viewport Display dropdown.

Now right/click on the Wireframe entry and choose Assign Shortcut on the popup menu.

Type in your required shortcut key combination (I used Ctrl-Alt-W) and that shortcut will then toggle Wireframe view on any selected object when you're in Object Mode.

If you now go to Edit > Preferences > Keymap you will then be able to see that added entry. To make that combination permanent click the bottom-left 'hamburger' icon on that dialog and click Save Preferences.

Thank you verymuch

You're welcome. In fact, if you have Auto Save Preferences checked on the Preferences save menu that shortcut will be saved automatically when you exit Blender.

Noted one more question is there any way to view without solid shading activated like wireframe with x ray mode

Only on all objects in the scene by toggling into Wireframe and xray view with Shift-Z as far as I'm aware.

Okay, thank you..


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Armature Posing Abnormal Hip Line & Legs Cave In
I made an armature and connected it so a stick figure I made. The issue I'm running into is when I bend the knees of the armature. The upper thighs of the figure begin to cave in, and a line appears in the hip area. This is an issue I've had for a while that I normally fix with sculpting, but I'd like a more permanent solution.
I've tried editing the weight paint of the hip area and the legs, but can't seem to find a fix. Any advice or links to a video on this topic would be appreciated. Thanks

Hello please share your file (remove the top of your character as it is not useful): https://blend-exchange.com/

Done, I had a minor revelation that I think may solve the issue. I tried adding loops before parenting the armature to the figure and then did automatic weights and it seemed to help. Is this the way to go, or is there another route?

Put the Subdivision Surface modifier under the Armature modifier so that it's the low-poly mesh that is animated, not the (virtually) subdivided mesh (also maybe activate the Preserve Volume option of the Armature modifier):

Thanks a lot! And Preserve Volume did make a decent difference, it kept some of the width of the arms and legs when they were moved. Will keep this in mind for the future


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Alt + left-click not working anymore in Blender 2.8?
I don't know why but it seems Alt+LMB is not working for edge loop selection in blender 2.80. Is it a bug? Or is there's a new shortcut for that?

Did you make your Left Mouse Button your select button? It is Standard in 2.8 right? Did you have 2.79 installed before and it took the config from there?

Left button is the standard in 2.80. And i uninstalled 2.79 before using 2.8. I've got the solution,it's only double click(left click).

If you are using Linux Mint this will be an issue as Alt is used for moving and resizing windows.
Go to System Settings > Windows & then go to Behavior tab. Inside there you'll see Special key to move and resize windows and set it to Super and Alt + LMB will work just as fine.

As said by morph3us, you can use Double Click on edge for the edge loop selection in edit mode, for Blender 2.8.
With default preferences (i.e. when you do Load Factory Preferences):

You can select edge loop by Alt + Left Click on desired edge.
Shift + Alt + Left Click  for multiple edge loop selection.

With modified preferences(i.e. Input > Emulate 3 Button Mouse checked):

You can select edge loop by Double Click on desired edge.
Shift + Double Click for multiple edge loop selection.

I am using Blender 2.8 beta on default settings and the shortcut is AltShiftLMB.

I'm using 2.79b and this work for me

Go to Edit > Preferences > Input and turn off Emulate 3 Button Mouse.

Its just "double click", without the Alt button pressed, now.
Seems it got reverted back to the original behavior, you need to press Alt+LMB to select an edge loop.

Does not select edge loop for me

You are right, it changed again. I updated my answer! Thanks for pointing it out!

None of the above works for me in blender 2.90.1.
When I press Alt, the bottom of the window indicates that I should left click to loop select, but when I click, nothing happens.
Alt+Doubleclick = nothing, Alt+Shift+Doubleclick = nothing, Shift+Alt+Left Click = nothing.
It turns out it's my operating system (Linux Mint) that uses the Alt key for window operations. I used the solution where I re-assign Alt to the Super (Windows) key in the operating system, and now Blender works.

I'm using version 2.82, so I don't know if would work for you, but it definitely works for me.
Go to Edit > Preferences > Input and under the Mouse dropdown, untick Emulate 3 Button Mouse.

I'm using 2.93, I think. I dug through the keymap in preferences and found that mouse button 4 will select loops on my system. I didn't have time to do more research but maybe this could be a good place to start for some of the more highly motivated among us. Hope this helps.

I think I figured it out. In the keymap dialog in preferences under Mesh - Loop Select - Loop Select, mine were set to MB4 and MB5. Click the arrow to the right to reset to default. I'm using Corsair peripherals and will check ICue to see if that had something to do with it.

If you have a fix, here, it's one of those odd cases? I think it's be fair to close this one as not needing an answer.. if that's not the case, go ahead and edit to explain why, and we can re-open for you.

I'm in v3.12 Windows 11, and none of the Alt combinations work with or without 3 button mouse emulation.
Ctrl + Double-Click does work, for both edge and face modes.

ALT+SHIFT+LMB should work in v3.1.2 with the default keymap.


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Customize blender camera distortion
I have a camera sensor and have done the calibration to acquire the intrinsic. Now I want to re-produce the calibration images in blender, and hopefully the rendered images can perfectly align with the captured ones. How can I set the measured radial and tangent distortions to the blender camera if I have K1, K2, K3, P1, P2?
I can add distortion via the lens distortion node, but there's only 1 number to set, and doesn't support tangential distortion (I guess?).

Does this answer your question? Distort a Rendered Mesh

You can't set tangential distortion ($p1$,$p2$) through the interface. Only radial ($k1$,$k2$,$k3$)
To set camera intrinsics load a video file or image generated with the known camera and lens in the Movie Clip editor
Int the Track tab you will find the camera and lens settings. Set Lens size in mm or pixels, Image center, sensor size and distortion coefficients.

Then use the compositor use a Distort-> movie distortion node. Set it to use the distortion information from the clip loaded in the movie clip editor.
There are two modes on the movie distortion node: distort or undistort.
So you can choose to undistort the video or images from the camera, or distort the images generated on blender's camera to match those of the real camera.

Note that there is also a lens distortion node in the compositor, but that is meant more for "artistic" purpose and has no way to set precise camera intrinsics.

I'm not aware of any built in  way to distort the camera directly in the 3D environment and the viewport, only the rendered pixels of the image can be distorted as far as I know.
Note also that a lot of 2D software that deals with lens distortion uses the maximum dimension of the image to convert pixel coordinates to normalized ones, and blender uses normalized image coordinates (aka measured in -1 .. 1 space, not in pixel space)


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Calculating split normals using python?
I'd like to use a python script to transfer normals to a new uv layer. Here is my first attempt:
import bpy

ob = bpy.context.object

for loop in ob.data.loops:
    normal = ob.data.vertices[loop.vertex_index].normal
    ob.data.uv_layers["XY"].data[loop.index].uv = (normal.x, normal.y)
    ob.data.uv_layers["ZW"].data[loop.index].uv = (normal.z, 0)

What I eventually want the script to be able to do is read custom split normals. I heard this was possible through the use of this script. The normal section underneath is supposed to calculate the normals using calc_normals_split or calc_tangents. However every time I try to incorporate this into my script I keep getting error messages or the result comes out as just one color. If anyone could help me to make it work would be much appreciated.

your url points to the man page for MeshLoop, but there's no script there.  Did you mean to point to an example?

Yeah, that's correct. After using ob.data.calc_normals_split() you access the normals with loop.normal. What error message are you getting? Make sure you are in object mode and not edit mode when you run the script.

MeshLoop.normal
As commented by @scurest

After using ob.data.calc_normals_split() you access the normals with
loop.normal. What error message are you getting? Make sure you are
in object mode and not edit mode when you run the script.

Look at the loop normal, rather than the vertex normal to get the custom split normal values.
Test script, using foreach set to set the UV values rather than directly looping over them.
import bpy
import numpy as np

context = bpy.context

ob = context.object
me = ob.data

# get or create uv layers
xy_layer = me.uv_layers.get("XY") or me.uv_layers.new(name="XY")
zw_layer = me.uv_layers.get("ZW") or me.uv_layers.new(name="ZW")

# calc split nomrals
me.calc_normals_split()

norms = np.empty(3 * len(me.loops))
me.loops.foreach_get("normal", norms)
nx, ny, nz = norms.reshape((-1, 3)).T
nw = np.zeros(len(nz))
xy_layer.data.foreach_set("uv", np.array([nx, ny]).T.ravel())
zw_layer.data.foreach_set("uv", np.array([nz, nw]).T.ravel())

Here is what it looks like when I run the script and extract the uv coordinates in the shader editor  https://ibb.co/T0szQtm and here is how it should look https://ibb.co/bFdCM3F I think something is going wrong when It transfers the normals to uv coordinates.

Whoops, Required a transpose before the ravel.


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How to run an Alpha Build?
This would seem to be a dumb question since I can't find anyone asking it before....
I thought I would install an Alpha build for the first time (2.93 - on a Windows PC). I unzipped all files to a different directory from 2.92 but I cannot find the exe file to run it!
Should I have installed all the files to the 2.92 directory? Was really hesitant to do that since I want to be able to remove it easily, if necessary. I would think it not necessary to do this since if I never had Blender installed prior how would I run an Alpha build?

Please do not add "solved" as part of the title. Mark the answer that
helped you as accepted instead (https://i.sstatic.net/qBQh7.png).
Please take the [tour] to understand how the site works. Read also:
what does it mean when an answer is accepted?

The alpha build should have an EXE file, if you downloaded it to a Windows computer.
If you used a different OS to download it, the website may have selected a different binary format. Alpha and beta builds should always be able to be run simultaneously.

Thanks, but it definitely doesn't. If I go into the directory for 2.92 I see all kinds of files including the Blender.exe, however in the 2.93 directory there is just ONE file - python39.dll (and some other directories, of course, but none have the exe file.)

@lensman ok, that is an extraction error, a download error, or something that isn’t on your end. Try re-downloading the archive: the binary file SHOULD be there.

And I just double checked - it was the correct OS file I downloaded. Windows zip file uploaded at 29 May 2021 05:47:30

"that is an extraction error, a download error, or something that isn’t on your end. Try re-downloading the archive: the binary file SHOULD be there. – ZargulTheWizard"  Thanks. I guess that is all I can try.

There must have been something going wrong. I always download the zip from alphas or betas, unpack it and in the blender directory there are all kinds of files which looks just like the regular install, including the blender.exe program file.

SOLVED (I think). Checked my download file and it was only 79MB in size and should have been much larger!


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Building Blender as Python Module based on Python 3.7?
I am pretty new with blender, I am trying to build it as a python module, which I successfully managed to do following this link blender-python.
However, this builds the module for python 3.9 but I want to to build it for python 3.7 since I want to incorporate other functionalities which use libraries in python 3.7.
After some research I found this answer and tried that too but I am unable to achieve any success. I would really appreciate if someone can help me on this issue.
Q: How can I build blender as a python module based on Python 3.7?

You have to use a version of Blender that used Python 3.7 as its Python. This will also mean checking out a version of the SVN dependency repo for that version of blender (although I think checking out the tag from the git repo and running make update will do this for you).
From the other answer you mentioned:
"The Python version requirements are the same with building a regular blender binary (if Blender us using Python3.6 then there is NO WAY to use another version - 2.7/3.2/3.6 will all fail)."
I believe this article was written for Blender 2.8, so try doing
git checkout blender-v2.80-release and then make update and see if it'll build.
I := Python 3.9, because the walrus operator is awesome!

Thanks a lot for your input, I'll take them into consideration and try building again. Reason for using Python3.7 is that, I want to use ML frameworks and some additional libraries which currently does not support future python3.9. However I agree with your suggestion on using python3.9.

Hi Joseph, I have checked out the Blender 2.80 branch, However I am having trouble switching to correct svn branch as I cannot find the on that I need. Do you have any idea where I can find it?


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Where can I add Color settings(filmic) for saving .PNG
Where should I add this setting for png to export with correct color settings, since now blender by default exports using 'Standard' color profile
I found this line - bpy.context.scene.view_settings.view_transform = 'Filmic', where should I add it?
thank you!
bl_info = {
    "name": "Image to Photoshop",
    "description": "Send image as new layer of photoshop",
    "version": (0,7),
    "blender": (2, 8, 0),
    "location": "image",
    "warning": "",
    "wiki_url": "",
    "tracker_url": "",
    "category": "Import-Export"}

import bpy
import os
from . import sync_tools

translation_dict = {
    "en_US" :
        {("*", "Send image as layer of photoshop")
            : "Send image as new layer of photoshop",
        ("*", "Open on Photoshop")
            : "Image to Photoshop"},

js_name = "img_open.jsx"

###################################################
class IMAGE_OT_ToPhotoshop(bpy.types.Operator):
    """Send image as layer of photoshop"""
    bl_idname = "action.to_photoshop"
    bl_label = "Send image as layer of photoshop mjasu"
    def execute(self, context):
        # Generate file path
        img_path  = sync_tools.set_temp_fpath(context,extantion = ".png")
        # Save img file
        bpy.ops.image.save_as(save_as_render=False, copy = True, filepath=img_path, relative_path=True,)
        # execute Photoshop Script
        sync_tools.execute_js(context, js_name, img_path)
        return {'FINISHED'}

def menu_func(self, context):
    self.layout.operator("action.to_photoshop",
        text="Open on Photoshop" )

def register():
    bpy.utils.register_class(IMAGE_OT_ToPhotoshop)
    bpy.types.IMAGE_MT_image.prepend(menu_func)
    bpy.app.translations.register(__name__, translation_dict)

def unregister():
    bpy.app.translations.unregister(__name__)
    bpy.types.IMAGE_MT_image.remove(menu_func)
    bpy.utils.unregister_class(IMAGE_OT_ToPhotoshop)

if __name__ == "__main__":
    register()
#########################################################

Setting save_as_render to True should do the trick if CM is set to filmic (it is by default). Doesn't it? bpy.ops.image.save_as(save_as_render=True) is the default so I guess there is a reason why the add-on author set it to False... Consider that png is the worst file format ever when it comes to CG: https://blender.stackexchange.com/a/106671/

thank you very much, I ready your to answer only now but yes, I found out that the save us option set it to my current settings, now all goes great, thank you!


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How do I fix - "CUDA error : Launch failed in cuCtxSynchronize()" and "cuCtxCreate: Launch failed" in cycles
I'm using 2.78 cycles with experimental and it have been stable until recent when this errors started.

I haven't started to work with the scene, the only thing I have don is setting up the character.

I did update my driver for my GTX660 to version 373.06. The only problem is that blender do have stability issues now but GPU rending do work.

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

authors: Дмитрий Комарницкий


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Cycles does not show textures
So, I DO have the UV unwrapped, looks alright in Blender render, not when I switch to Cycles though ...

Would post the file, its 70 mB though... for some reason,...
EDIT: not sure about how my question is different from the similar question asked, but I did not see any solution in the How to show textures in the 3D View editor? other similar thread/question....

Possible duplicate of How to show textures in the 3D View editor?

Hmm checked, 'his' solution did not worked for me.... no idea where the problem might be...

On this vase you have three materials in the material slots tab. As you can see in your screenshot, you are editing the second one at the moment. Trouble is, that material (I know that from the last file you provided in another question Half of my mesh/texture is blurred) is not assigned to any face of your model, that's why you do not see the texture.
Either select all faces in Edit Mode and click the assign button in the material tab. This will assign the currently active material to the mesh faces. Or alternatively, delete the other materials (if you don't plan to use them). Then make sure the image texture node is selected in the Node Editor, and the 3D View is set to textured. That should do.

Hah, that was so funny. The solution to this issue was solved by ONE click on the Assign button :) Totally did not know you need to assign material first. Thanks man!

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


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Half of my mesh/texture is blurred
For some reason, half of my texture on the mesh is blurred... I did not use any special nodes or settings or anything, just applied an Image Texture node...
Any idea why this might be?
Here is the .blend file

and a screenshot:

Thanks guys

The blend you have is missing the texture. You can pack all external data like images with File -> External Data -> Automatically Pack Into .blend. From first guess though, I feel like Blender stretched your texture. Did you manually unwrap or Smart UV Project, or did you just unwrap without seams?

Ah yes, thanks man, was wondering if the file will include the texture/image as well.... Yeah, forgot about the seam! Cheers

You'll need to provide a proper UV map to make this work. The reason why it looks like this is that currently your UV map is stretching just horribly, check this screenshot:

When I select the bottom of the vase, I can see that those faces cover a very small area of the UV editor, causing the texture to stretch like it does:

In essence, 75% of the surface of the vase are mapped to something like 4% of the UV space. This just cannot work. Try unwrapping the vase by placing seams down the side on two opposite sides, and also around the n-gon on the bottom, then the unwrap function will give you something like this:

The vase then will receive the texture like this:

Check the Blender manual on UV unwrapping techniques for further information:
https://www.blender.org/manual/editors/uv_image/uv_editing/unwrapping/index.html

Ah right, forgot about the seams!


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Default T Pose altered in edit mode
This is a really noob question which must have been answered somewhere but I can't seem to word my question adequately to find any posts that specifically answers my question...
Anyway, somehow I completely messed up by changing the positioning/angles of my T pose (A pose in this case) in edit mode and hit save+quit before realising I did. I'd know how to reset armatures back in pose mode but is there a right way of doing it in edit mode?
(I basically want the model in the image to be facing front/centred/angles adjusted etc but I'm not sure how to fix it properly)

.blend file is here if needed:

could you provide a .blend file to be able to help you?

I may be not comprehending your question exactly, but it seems that you only want to turn him around to face front & center.  If that's the case, select the whole armature  in Object mode, and rotate that in the Z axis.  If your character has been parented to the bone assembly, it should rotate also.

You can go in pose mode then select all and Alt+R to remove the rotations. Now, you have bones constraints here: disable them. After that you may have your rest pose. Last thing: Alt+R again on the armature in object model to be aligned with axis


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Question about mirror modifier
I was doing this model with a tutorial. However, when I used the mirror modifier along the x-axis, no object appeared, and for the y-axis, the object stuck to the original object. Is it normal?
x-axis:

y-axis:

I wanted them to appear in this position, how can I make it?

For the moment the X axis makes the mirrored object overlap the original one, and the origin of the object is not correctly placed. You need to:

Apply the rotation of your object if you want its local axis to be aligned with the global axis (CtrlA)
Put the origin of the object where you want the center of the Mirror to be. For example you can use the Transform Affect Only Origins option to move the origin (don't forget to disable the option once you've moved the origin):

It works, thanks.
https://imgur.com/a/KEmYPxg

Great then.........    ;)


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How can I make a material randomize a texture per object?
Let's imagine I have a scene with a thousand identical cube meshes. I want to apply the same material to all cubes, but have each cube randomly display one of my 3 or 4 image textures. Say, some cubes will be checkered, others will be dotted and others will be striped for example.
Is there a simple way to achieve this in Blender 3.6?

There must be a more intelligent solution but you could use an Input > Object Info node and its Random output to mix your Image Texture nodes through a Color > Mix Color node, plug the Object Info into a Color Ramp in Constant mode so that it picks one or the other image randomly:


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Mesh lines in the shape of a circle do not render in my model
I have a 'Solar System' model for my website, I have already placed the spheres that represent the sun and the planets, and I have also added unfilled circles that represent the orbits, I have created these in add > mesh > circle, too I have animated the entire model, when I finished it looked like this:

The problem is that when I move to the 'animate' section, the circles that represent the orbits disappear, even though the objects continue to exist in scene > collection:

Even when I export my model in .glb format to use on my website, I am able to render the scene but the circles still do not appear, although the object that is created when importing the .glb contains all the figures in the scene:

Any help is welcome, I'm new to this. I use Blender 3.6.

Edges on their own don’t show up in renders. They can be converted to curves which can be given thickness.

Select the orbit line
In the Object menu Choose Convert > Curve
In the Data tab of the Properties panel, find the Geometry section and set the Bevel Depth to something like 0.04
You should see the edge curve sort of "inflate" into something like a ring

That's it! thanks bro


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How to make Lanterns rising in sky form an infinity logo
I am working on a Live action CGI shot for Diwali where we see sky lanterns rising in the sky and then few of those lanterns starts to form the shape of infinity. Any ideas or tips on how to form the infinity sign with lanterns. Also, i have made lanterns rising animation with geometry nodes.

you can use this node setup, which "just" moves them from a volume cube to a bezier-infinite symbol.

result:

Thanks a lot Chris, this was really helpful, Can you please also guide me on how to set this up so that only few lanterns form the sign, rest keep rising towards the sky ?


text:
More time is spent on render preparation than on the actual rendering. What can I do?
I'm new to blender and I'm stuck on this giant unsolvable problem that no one seems to have any solution for.
I've modelled a quite complex scene in Blender: roads, bridges vehicles, buildings, trees etc. When I try to render an animation using cycles, it takes about 5 minutes per for scene preparation alone. Things like synchronizing scene, update mesh, building bvh etc. The thing is, that actual rendering only takes like 30 sec per frame. So 90% of the time is consumed for building the scene.
I've tried many things like reducing samples, light bounces etc., but they only reduce the rendering time and not the scene building time.
It has come to a point that I can't really output anything. I might have to leave 3d modelling because of this.
Is there any way that I can save the scene building cache and use that for every frame? Only vehicles in my scene have any animation. 95% of my model is static. I don't understand why it has to be like this. I'm sure I'm missing something very basic here.
What can I do?

Welcome to the world of rendering. In fact, rendering takes time. If you are new to blender and that is something annoying to you: "leave 3d modelling" since this will most likely always part of your work, at least to present your models. However, this issue is not "unsolvable" but depends on your hardware and your scene. Each scene is different so general advice is: optimize your scene using collection instances, dupli verts etc. and especially understand the principle: The more unique data you have, the longer it takes to "prepare the scene".

Also make sure you haven't got too many polygons. If you have a subdivision surface modifier bring it down to max 2 or 3. Don't use too big textures. For a close up render for something like a road or car 5k or 6k textures is more than enough (For weak lcomputers and gpus go and take 3k or 4k but if it is powerful then 6k is ok).

If scene preparation takes a very long time, here are a few things to consider/try:
General
Before the actual rendering part starts, a few things need to happen. All the necessary data in your scene needs to be turned into its final form that will be handed off to the renderer / loaded onto the render device.
For every object, all modifiers will be applied and meshes will be triangulated. The resulting geo will be copied to the memory of the render device. Also, a BVH will be created for every object.
Any textures also need to be copied.
(disclaimer: no renderings expert, please correct in the comments if any of this is wrong)
Now, this gives us a few hints to possible optimizations. I'll focus on things concerning preparation times.
I'll start with the simple one:

1. Textures
Every texture needs to be copied, which takes time in the preparation phase. Reduce size and amount if possible. Less data = shorter times to copy.

2. Objects
Count: In general, it will be faster to have fewer objects with more polygons than many objects with fewer polygons (if both have a similar total poly count) as each object is treated separately. So, join as many objects as possible to reduce the number of objects. (You might want to keep a copy in a disabled collection, so you can go back at any time)
Modifiers: Modifiers have to be evaluated before rendering. We can take that time from the preparation stage by applying all modifiers beforehand. (Again, keep backups if you need to go back.)
Then we come to the BVH part. BVH can accelerate raytracing quite a bit and is usually a good thing, when most of the render time is actually spent rendering. But BVH building takes time. Again, fewer objects will make this faster, because a BVH will be created for every object. (please correct me if this is incorrect.) Also, we can accelerate BVH building by turning off "Use Spacial Splits" in the Performance Tab under Acceleration Structure.
This is something you'll need to try and see what the impact on overall render time is.

3. Meshes
Poly count: Again, we have the simple rule: Fewer polygons will be faster to process and to copy. A few things to watch out for are: (1) High poly background objects, that could be simplified a lot without appearing visually different in the final render. (2) Having the Subdivision Surface modifier set too high. See what the lowest setting is without affecting your result.
Instancing: Another way to avoid unnecessary geometry is to use instances rather than copies of meshes. This means that two equal objects use the same mesh data 'under the hood'. Therefore, the mesh will only be copied once to the renderer.
In your example, that could be a building. If the same building appears twice in the scene, you can make sure that only one instance of the mesh data is used for both of them. This happens automatically when you duplicate with Alt + D rather than Shift+D. If you already have made duplicates, you can select all objects, you want to use the same mesh and press Ctrl+L -> Object Data.
In this screenshot you can see that I have two Cube Objects using the same mesh. (The number 2 indicates the number of users of this mesh.)

4. Debugging
Sometimes, for no apparent reason, you can experience a great loss of performance by one single 'thing' that's not working correctly in your scene. So it's good to look for the cause. With more experience you'll be able to judge if a scene takes roughly the time it should take, or if something is actually wrong.
Here are things to try: Turn OFF rendering on all objects and start with one or a few and see how long it takes. If it renders quickly, add some more, and so on. You don't have to go one by one of course, the important thing is to narrow it down and find the problem.

This is by no means supposed to be a complete list, rather than a good starting point to cover the most common cases. Again, feel free to add more information.
And as always: Happy blending! ;)


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Aperture Science portals using OSL
I am wanting to create Aperture Science style portals, And I’m aware of various compositing techniques to do this, but to make it more flexible I am thinking about using Open Shading Language. I do not know much about OSL, but the principle in mind is to basically have the shader take a ray trace that’s coming at it, and send it out of a different object, translating the first object’s local space into the other’s (possibly with a tiny bit of offset so it doesn’t then collide with the second object, but that may not be necessary if we can take normals into account)
In short, is this or a synonymous implementation possible, and how would it be done? I’ll be looking up resources on OSL in the meantime if I can.
This is what it looks like in Portal 2:

As you can see, one portal is connected directly to the other. For clarity, the small swirly blue-and-orange icon in the center of the screen (showing over the bottom of the orange portal) is a crosshair and is unrelated to the effect at hand. A holographic outline of the orange portal also shows through the testing sphere, and that is also unrelated.

Could you illustrate/reference the exact effect you're after?

@RobinBetts I edit added a screenshot of the effect in Portal 2.

You might find this useful: Youtube: How were the portals in Portal created? | Bitwise

@MarkusvonBroady will check this out. Thx. (Third parties: do not consider this as an answer to the question unless later informed otherwise)

I personally don't think OSL has anything to offer here, even if you go the (nutty) route of taking over all the shaders and casting all the secondary rays yourself. If you just diverted rays, you are in the territory of Rich Sedman's refraction methods? AFAIK the only reasonable route to getting one camera's view into another's at frame n is compositing, as here. The interesting problem is then how automatically to coordinate the camera(s) views in separate scenes, with minimum hassle.

@RobinBetts Cool lens thing, which I might use for something else. Yes, flexibility is the problem. Thanks for trying. I do faintly remember something in the old blender internal engine where you could use another object viewpoint as a texture, and thus efficiently fake reflection, but of course that’s probably not in cycles. It seems that light probes do this automatically.

@Zargul .. as always.. hope to be proved wrong :)


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How do I save a frame as an image in Blender 3.0 VSE?
This question has already been answered here, but everything got changed around in Blender 3.0.  F3 now opens up this search menu which has not been very useful in finding what I'm looking for.
I would like to save this individual frame as a PNG.  How do I do it in Blender 3.0?  My Interface -> Editors -> Temporary Editors -> Render In setting is set to "Keep User Interface", and I would like to keep it that way if possible.

The first answer shown under the question you've linked above gives you 4 options. None of them is F3, did you try any of these? Because the F3 answer is about five and a half years old, the one by vklidu just 9 months.

Does this answer your question? How to save render?

I see in the screenshot you show that you pressed F3over the video preview window, you are supposed to render the image with F12 first then press F3 over the rendered image.

@mqbakamqbaka Oh, totally missed that looking at the screenshot. You're right.

Yes, that's why the the command search is displayed.

you can still save it here:

I am using a mac so i don't know your shortcut, but you can see it right beside the menu entry.
EDIT
The default shortcut for it is ALT + S. Shortcuts are Area specific so make sure you hover on the image when pressing this.


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How to programmatically add an effect strip
I have some test images. I want import all images into the sequence editor, one image per channel. But I want to add a transform effect strip for each image and tune it. I want to do this all programmatically.
This is my test python script:
import os
import re
import bpy

from bpy import context
scene = context.scene

path = "/path/do/images"
files = os.listdir(path)
files.sort(key=lambda var:[int(x) if x.isdigit() else x for x in re.findall(r'[^0-9]|[0-9]+', var)])

c = 1
scene.sequence_editor_create()
for f in files:
    seq = scene.sequence_editor.sequences.new_image(
        name=f,
        filepath=os.path.join(path, f),
        channel=c,
        frame_start=1)
    seq.use_reverse_frames = False
    seq.blend_type = "OVER_DROP"
    seq.frame_final_duration = 240
    # [INSERT TRANSFORM STRIP HERE]
    c += 2
    if c == 21:
        break

I skip one channel between images. I want to insert the effect strip in between.  I tried effect_strip_add:
bpy.ops.sequencer.effect_strip_add(
    type="TRANSFORM",
    channel=(c+1),
    frame_start=1)

But blender says:

ret = op_call(self.idname_py(), None, kw) RuntimeError: Operator
  bpy.ops.sequencer.effect_strip_add.poll() failed, context is incorrect

How do I programmatically add an effect strip?

Beware of the channel limit (32 IIRC?), unfortunately Blender has an upper limit on available channels for any media. If you add more than the limit, your media will stack at the same location on the top channel. My workaround is to metastrip this last channel of media and break it out into a new 32 channel stack (in the metastrip)

Oh. I found it.
Not need select. Just add new effect strip:
eff = scene.sequence_editor.sequences.new_effect(
    name="Transform",
    type="TRANSFORM",
    channel=(c+1),
    frame_start=1,
    frame_end=240,
    seq1=seq) # this last arg is target channel


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Achieving a feathered transparent effect
I am wondering if a feathered transparent sphere is possible to make in the internal Blender Render.
Currently I have this:
Would it be possible to feather off the edges or make the sphere get more transparent as it gets to the edges? Thanks.

You can do this with a Fresnel node or a Layer Weight node.  Both these nodes give higher values (close to 1.0) at grazing angles and lower values 0.0 straight on, and thus can be used to mix in pure transparency towards the edge of your sphere.

The difference between the two is the interpolation curve.  The Fresnel node uses the Fresnel function, which is technically meant for defining amounts of glossy reflection but still often gives pleasing gradients.  The Layer Weight's Facing output uses a linear gradient from straight on to grazing angles.
Cycles

To use this to control the transparency as you want, mix a pure white transparent shader with your colored transparent shader and plug the Fresnel or Layer Weight into the Mix Shader's Fac input.  The above result used the layer weight node, like the following nodes.

Blender Internal

Though Blender Internal has no specific Layer Weight or Fresnel node, you can make one from scratch with a little bit of vector math.  Just use it to control the alpha of the output node.

This uses a Converter > Vector Math node to take the dot product of the View vector and the Normal vector.  Here I have also added an RGB Curves node to adjust the falloff curve manually.

Thanks for the answer, but is this possible in Blender internal? Even with material nods in the internal render, I don't think I can use Layer Weights or Fresnels.

@Tritofic  I'm not sure, I know nothing about BI.  You may be able to do it with volumetrics though.  (BTW, you should add the [tag:Blender-Internal] tag to your question if you're asking specific about BI.)

Oh, I apologize. I just added the tag now. In the internal, I found a Fresnel option in the transparency settings, but the dark is on the outer part and the light on the inner part.

@Tritofic You can use an Invert node to flip the black and the white if needed. Also, see the accepted answer for this question about how to emulate the Layer Weight node in Blender Internal.

@Tritofic  OK, I updated my answer with a BI solution.


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Un-weighted painted vertices moving with bone
I am trying to rig my model and need to weight paint the bones to the proper body parts. I chose to parent my model to the rig using empty groups, but after adding weight paint to, for example, the leg, this occurs: https://gyazo.com/7a71be9641c3366da4dde5027e725459 .
Could this be because I haven't finished weighting all of the bones? Why is this occurring and how do I fix it? I apologize if this has already been asked.

Try checking to see if any child bones (bones which move when you move the "parent" bone) of the bone you are moving have weight on the problem area.

Thanks, that did the trick. I'm a little embarrassed I didn't think of that.


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Python - how do i access keymap entries from the new tool system in custom keymap?
I can read keymap items from the windows manager. This code retrieves the keys in the 3D View, Object Mode section for example:
    wm = context.window_manager # Blender window manager
    keymaps_3DV = wm.keyconfigs.active.keymaps['Object Mode']

But this reads just the entries from the old tool system. The new tool system for the tool shelf are not to retrieve this way. They are not in the tuple.
What is the way to access this new builtin keys? Is this even possible?

Example script to test. Open the hello world panel to write the tuple content into the console:
import bpy

class PT_PT_PT_HelloWorldPanel(bpy.types.Panel):
    """Creates a Panel in the Object properties window"""
    bl_label = "Hello World Panel"
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'UI'
    bl_category = "View"

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

        row = layout.row()
        row.label(text="Hello world!", icon='WORLD')

        wm = context.window_manager # Blender window manager
        keymaps_3DV = wm.keyconfigs.active.keymaps['Object Mode']

        print(tuple(keymaps_3DV.keymap_items.keys()))

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

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

if __name__ == "__main__":
    register()

EDIT, the trouble in my case seems to be a custom keymap with some modifications. As a bravery test, i created a new keymap from the default blender keymap. And as a result i don't get any entries in the tuple at all with this code:
import bpy

keymap_tuple = bpy.context.window_manager.keyconfigs.active.keymaps.keys()

print(keymap_tuple)

what do you mean by "new tool system"? did you create this on your own?

No. The "new" tool system is the one that is used in the tool shelf. All the entries which are not in a category, but has now a own entry. 3d View Tool: Select Box, 3D View Tool: Select Circle etc.


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How to set custom vertex normals for certain vertices using python?
I am struggling to set custom vertex normal vector just for certain/selected vertices in an object with python. I searched through the documentation and forums but nothing really helps so far.
This question/answer answers only to how to set split normal to a whole object. However, I want to set custom normals to just some parts of the object. See the picture below:

Q: How can I add custom normals just to certain vertices in and object?
Would be helpful if someone could share something simple as possible.

Does this answer your question? There is a way to add custom split normal use Python API?

Nope it doesn't...I still don't know how to set custom split normal only for certain vertex normals in an object

Edit your question, add what's wrong with the linked answer, what you've tried or what you'd like to get to your question in order to re-open it @skywalger

done, It shoud be now more understandable what I want to achieve

Example of assigning custom normals based on vertex selection. It's just a slight modification of the code given in this answer and assigns a custom vector to vertices in selection.

Run the script in Object Mode and enable show_split_normal property in Edit Mode:
import bpy

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

me.use_auto_smooth = True

# Normal custom verts on each axis
me.normals_split_custom_set([(0, 0, 0) for l in me.loops])

# Set normal for selected vertices
normals = []
for v in me.vertices:
    if v.select:
    # if v.index in (0, 1, 4): # Alternatively you can ask for certain indices
        normals.append((0, 0, -0.5))
    else:
        normals.append(v.normal)

# make csn's all face up.
me.normals_split_custom_set_from_vertices(normals)

#me.free_normals_split()

Note: As of 2.8x show_split_normal property is part of the Overlays menu:

thank you thank you thank you :), that is exactly what i needed and didn't know how to. I just replace the condition "if v.select" by "if v == me.vertices[n]" and that is it

Better ask for the index of the vertex: if v.index == 1: @skywalger For the sake of completeness, I added how to ask for multiple indices to the answer.

@brockmann How to enable the option show_split_normal you mentioned in your answer? I was unable to find any information about that option.

I think for consistency it's now part of the overlays menu as of 2.8x @vvoovv: https://i.sstatic.net/n6EYh.png

I see... It's the middle icon in the Normals section of the Overlays menu. I overlooked it somehow.


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Glass material is dark on cornea of eye
I've tried to research this, but none of the solutions I found worked for me. I'm really just experimenting with modeling and materials, so this isn't really suppose to be anything.
Here's the link to the .blend file:

I'm trying to create an eye using the cycles nodes. From following tutorials, my understanding is that I should have an inner sphere with the color materials, and an outer sphere with a glass shader on it to give the eye some shininess and reflectivity. Unforturnately, the glass material looks very dark. If I pull the cornea sphere out of the socket, it looks like a perfectly decent glass ball, but when it's in the socked, it's incredibly dark. I'll attach images of the rendered version and of my nodes setup.

If you want to provide files for review, please use exclusively http://blend-exchange.giantcowfilms.com/ and post the link into your question. Files from other file services tend to "vanish" over time which makes your question and possible answers eventually less useful.

You can use the edit link below your post to paste the link into your original question. I fixed it for you.

Try mixing the glass shader with a transparent shader, usually helps a bit. Also change the color of the glass material from the default 'white' to a true pure white

I'm already mixing it with a transparent shader, with 'is shadow ray' and 'is reflection ray' as the factor. I had already changed the color to pure white, but it still looks like it does in the image.

I had accidentally applied the glass material to the inner eye as well as the outer eye. It was dark because there was nothing for the light to bounce off. It looks much better now.


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blender renders nothing
i've made a bus model for my little project, on the earlier version of my model it renders just fine, on this version it just doesn't show up in the renderer, just pitch black,on materials and texture its fine, render just shows nothing, here's a screenshot and my .blend file that might help you to understand my problem

There seem to be no lamps in your scene

Possible duplicate of Object renders black

no its not like that, its a different case, and for lamps there is actually plenty, its just below the cylinder in the items list, and you can see there is visible lights reflecting on top of the bus at the material view so no, its a different one i think

The .blend file link doesn't work.

For future questions please use only the "official" upload service http://blend-exchange.giantcowfilms.com/ . Files on other services tend to "vanish" over time, thus making the question and possible answers eventually less useful.

You turned off the Combined Layer Pass in the scene
Go to the Properties Editor > Render Layers Tab > Passes and activate the Combined layer pass


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How do I create a test room for modeling and simulations?
How do I create a low poly room with one door and one window in clean white style that looks nice.
I want to have a clean testing room to mainly test simulations in and also test materials for models.
The biggest problem I have is to create a node for the texture, I don't want to use a bitmap texture because they create unnecessary problems when rescaling the room for things like planes.
I do want it to at least look like it is a photo when the image is compressed as a jpg
This is kinde of what i whant.

This is what I have.

The two bigest problem I have is that it is grey and the flore feels un-natural.

This is the best I did get by editing the light. I did set the exposuer to 2, sampling to Final and light path to Full Global Illumination.

It is very low in detail in the corners.

What have you got so far, where exactly are you stuck in your workflow? Please focus your question on specific technical problems that you encounter. As it stands this question is too broad and very opinion based, more suited for a forum format like https://blenderartists.org or other online communities

I have fixed both of you'r requests. White clean like the white rooms in Resident Evil is not a broad description if you have seen them. A short god answer now, should not need to be longer than two paragraphs.

It would suggest adding more light to the room since it looks quite dark at the moment. And maybe add a bump map to the floor so it looks a bit less flat.

I'v uploaded the prodject


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Inserting keyframes from node editor is not working
I followed the following post to try keyframing assigned material to an object
blender.stackexchange.com/questions/64986/keyframe-objects-active-material-from-material-slots
I followed the steps mentioned there exactly and got the same results, however when i insert keyframes for any value in any node i get no keyframes in timeline or fcurves, only there are keyframes in dope sheet, and no animation could be run in the viewport. I'm currently in blender render, and i wanna run it only in the viewport, i don't need to render it using blender render.

In the header of the graph editor and dopesheet, there is a button with a cursor on it, curves will only display for a selected node while this is highlighted. How complex are the materials? Is it just a colour change or a texture change?

just a color change, exactly the same as the above link. it turned out that, as you said, curves are displayed after i select a node. however, color changes are only displayed in viewport when i drag the factor slider, as seen in the link, but when i play animation, nothing changes in viewport

after some search, i thought that node changes can't be rendered in viewport using opengl,  however, it does render in viewport with opengl, as i told you, only if i drag the slider in a node, bout doesn't work when playing animation in timeline. i wonder why ??  by the way it only works when i render using blender render

I think it is a limitation of the material nodes and is most likely related to the dependancy graph. Changing the node value updates the viewport but changing the frame doesn't read the keyed values from nodes.

As you only want to change the basic colour, you can key the diffuse colour value instead of using nodes, this is a more reliable way to have the 3Dview updated.

Like other values you can hover the mouse over the colour and press I or right click RMB on it and choose Insert Keyframe. A border is added to the colour swatch to show the keyed status.


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Export UV data on glTF file without splitting geo
When we export a mesh as a glTF file, it seems that the geometry is cut along the edges where there are UV seams. Is there a way to export the geometry with the UV data intact, without resulting in a fragmented mesh? Thanks!


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3.6.4 Tiff files won't open in premiere. Same project with 3.5 works just fine
I encountered a problem in 3.6.4. When the output is set to tiff, premiere won't open the files but same project file rendered with same settings in 3.5 works just fine. Also After Effects seem to open both files without a problem.
Same thing seems to happen to all renders in 3.6.4 making it unusable for my purposes.
Also the file size seems to be different.
Anyone have an idea what's happening here?

Thank you. I reported this now.


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The subdivision modifier destroyed the flat surface

This part of my sub should be flat but after the subdivision modifier, it became strange and far from flat.

hello could you please share your file? https://blend-exchange.com/

You can use edge creasing to keep the border from being affected by subsurf : select the border edges and either hit shift+E & drag, or increase the "crease" property in the sidebar ("transform" tab).

Thanks, Hadriscus!


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Mesh from imported sketchup model is not good enough for animations, gives weird reflections
I've imported a model from sketchup, where I filled two curved lines to get a mesh. The problem is that when I want to use it for an animation, the reflections show up weird on the final render.
Is there any way to fix the mesh/ make the material appear smooth?

It will probably take you far less time to model something like that cleanly from scratch, than it will take you to clean that up to an acceptable state

Hello ! Your mesh may suffer from any and all of these : inverted normals, double vertices, Z fighting and inside faces. Also the quad distribution should be as even as possible to avoid shading artifacts, especially on curved surfaces


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I would like to model this shape, but can't figure out how. I've tried booleans, modeling it and even connecting different shapes
As I said, ive tried quite some techniques, but none of them leave me with a clean enough topology to bevel the sides.

Hi. Please use a title that matches the content of the question. It should be descriptive but succinct, unique and identifying, summarizing the issue in such way that anyone searching for a similar problem is likely to find it. Use the [edit] link above, remove anything superfluous, avoid words like "this", "help", "issue with" or "question about". Remember, your title is the first thing potential visitors see, answers you get depend heavily on how insightful it is. See What is the problem of asking “How do I do this?"

Create a cube, remove its top face, scale the top edges except the back that seems to stay vertical:

Extrude up the back:

Bevel the edges:

Bevel the top vertices, create this topology:

AltE to extrude faces along normals, bevel the edges to keep them sharp, give your object a Subdivision Surface modifier:

use the subd workflow you and
add edge control
the bottom face can be grid fill

Hi, thanks for the post. This site is not a regular forum, answers should be substantial, stand on their own, and thoroughly explain the solution and required steps. One liners and short tips rarely make for a good answer. If you can, [edit] your post and provide some more details about the procedure and how it works, perhaps add a few images illustrating some steps and final result. See How to write a good answer?, otherwise it may be converted to a comment.


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Want to model and bend an aluminium facade panel, but can't figure out how. Do I need to use geometry nodes?
I want to model a small metal experimental panel to be used in a static render, but I can't figure out how to model it correctly, or bend it correctly.

This is the shape I'm trying to model correctly, the inner shapes are intended to bend, but when I try that, i fail. (see next pic) The topology is also very bad, but im still very much a noob.

As you can see, the bends are very wonky, and not smooth at all.

create additional edge loops if it doesn't band smoothly, maybe share your file so that we can give a try: https://blend-exchange.com/

https://blender.stackexchange.com/questions/50665/how-to-generate-a-metal-mesh/


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How to Apply alpha/texture to the entire object
I am trying to apply this alpha/texture to my object without manually painting with the brush, as in some areas it comes out with larger dimensions or undesired shapes at the corners. I have attempted to use nodes such as an alpha image and then a color mix, but it did not work. Additionally, I would like only the body, excluding certain parts such as the eyes or limbs.

the problem is most likely because of your unwrapping. You'll  probably need to unwrap the model by hand and after that it should be fine. Applying specific texture only to a part of you model is no problem. just select faces you want and in material tab add a new material and assign

Hello, Qatawneh.. welcome. A shot of your UV map would help us help you, here, I think, we can see  if @JiříHonzák is right.


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Textures are visible in Texture viewport mode, but disappear in Render and Texture Paint
I have a simple box with a texture on it, using a UV map. The texture displays perfectly in Texture viewport mode, like so:

However, when I switch to Rendered mode, it's just a grey box. If I try to use Texture Paint, it says I have missing textures. (Material mode is a grey box, too, but that doesn't trouble me) I don't understand this. I seem to have a texture, or else Texture mode wouldn't display a texture. But Blender seems to think I don't.
How can I force Blender to use this texture in Rendered mode?
My material settings:

My texture settings:

Add a sphere somewhere for ease of recognition.  Please show failed render.  Do you have lights?  Have you pressed 0 (zero) repeatedly on your numeric keypad .... to ensure your Camera View is the same as your User View ....  (If you make a mistake and press regular 0 zero you will need to press 1 (one) to see items .......... sorry for the potential lack of clarity) . Did you UV unwrap your 3D mesh?

Make Sure your 3D Mesh is UV unwrapped.
Your material must have a texture attached.
As a temporary investigation tool you may select  ... Material Shading [Shadeless] or add more lights to the scene.
Here is an example.

We are in the texture pane ... indicated with red and white checkerboard icon.
In the image above you see Object Name, Material Name, Texture Name ... next to the push pin. Reading that line verifies the attributes are linked. These names indicate an active hierarchy. Object with subordinate Material with subordinate texture.  They are linked, attached, bound.
It can be confusing that in 3D View Window you may see an image temporarily on your mesh.  Feature perhaps. During render only the texture pane setting will be rendered in Blender Render mode.
Because I created the object, then created one material while the object was selected, the material is bound to the object.  Next I switched to the texture pane. I created a  new texture immediately after viewing the material.  The check box for the texture is selected.  The texture is bound to the material.
I am simply restating the settings you see here for emphasis.  Type [Image or Movie].  Image source you see a filename from the hard disk. By clicking the button you will see a select file dialog.
More texture settings.

Mapping UV with understood default name. Influence [Color]

How can I "bind" a texture to a material, or a material to an object? There are materials in the material list, but I can't tell if they are truly attached to the object or not.

Select the object. Only add one material to your object at this moment.  Then only add one texture.   Start fresh.   If you have any failed material ... DELETE them to remove any accumulated mistakes.  Show your material and texture setting in your original question if you are allowed to do so.

Edited question. Thanks for your help so far.


text:
Why does Undo only sometimes work?
I can undo most actions, but some (mirror modifiers, some kinds of scaling) cannot be undone. Pressing Ctrl-Z does not reverse them (the actions show up in my undo history, but nothing happens when I press Undo).
I can undo scaling done with the S key, but not scaling done using this menu:

Undo works on most other actions, just not these ones.
I know switching between Object and Edit mode can cause problems for Undo history, but I'm staying in Edit mode the whole time.
What makes these actions "special" in that they cannot be undone by normal means?

O person with greater knowledge, please feel free to correct my deranged ramblings. When one writes a tool (an operator) in Blender, one has to explicitly state that it can be undone. The default behaviour is not to be undoable. That may explain some things. However I think that you are dealing with some bug. I belive that both of the actions you describe should be undoable. Does this happen all the time or only with a (set of) .blend(s)? If so, is it repeatable?

Adding modifier won't be undone from Edit mode because this is action with object, not with mesh (and when you are in Edit mode you're editing mesh). Could you clarify what is "Scaling using the Object menu" ? If you mean Object menu in the bottom 3D View, it won't appear in Edit mode.

Edited. I'm not sure what to call that menu.

Editing values from that menu is the same as editing them from Object mode; that data isn't applied to mesh rather than only stored as a property of the whole object, read the dfiference between that. So overall you face differences between what you can undo in Object mode and what - in Edit mode.

Hey, thanks for this - you led me to examine, and thereby inadvertently shed light on the cause of one of my custom shortcuts not being undo-able. I have M+MMB set to merge verts at center, M+LMB merge verts at first, and M+RMB merge verts at last - so M is the modifier key in this case... however I also have M set as a shortcut to Mark Seams. From a performance standpoint there is no conflict, however when it comes to undo functionality it seems to be confusing the Undo History, so any time I merge verts using this keyboard shortcut I can't undo it. I may need to rethink this key mapping. thx


text:
Is there a way to do this "splitscreen" partially-rendered effect?

In this example (not my animation), the right half is rendered, while the left half is unrendered (like what you would see in the Viewport when set to Solid mode). As objects cross the center of the screen, they become rendered/unrendered.
This is done to show viewers what's going on behind the scenes, so they can see how the shot was constructed.
How could such an effect be created in Blender? I am particularly interested in doing the left half (the unrendered bit).

I'd use a render border to render only one half of the shot, then overlay that onto an OpenGL render.

If using nodes isn't needed (they won't be taken into account while in viewport) you can define a render border; then while in camera view Shift+Z toggle will make render just like on refernce image.

How's this look?  (That's a frame from an animation which is too big to upload and I'm having trouble compressing it.)

You may easily achieve this effect using Compositing Nodes. I'll show you how to do it both for a still image and animation.

STILL IMAGE

First select the Slot 1 in the UV Editor window and render your scene using a Full render (F12).

Then change the slot to Slot 2, but this time render the active viewport using the Open GL render. Remove all the materials from your model. Check the Only Render checkbox, located in a Display panel of the Properties Shelf (N) and click the camera icon located at the bottom bar of the 3D window.

Save both images to your computer.

Now go to the Node Editor, press the Compositing nodes button and check the Use Nodes and Backdrop checkboxes. Then set up the nodes as pictured below. First add two Image nodes (Shift+A-->Input-->Image) and open both images you've rendered. Next create a simple b&w texture in gimp (with the same resolution as rendered images).

Use it as a Factor for mixing two renders (add a Color node [Shift+A-->Color-->Mix] and plug the image to its Fac socket. Add a Viewer node (Shift+A-->Output-->Viewer) to see the compositing result.

ANIMATION

You may do it in similar way. Go to Render header and set up things as you like in Dimensions panel. In the Output panel choose the path to the folder you want your rendered frames to be saved (in my case I created a new folder and named it 'full render'). Change the file format to JPEG.

Now choose the Render Animation (Ctrl+F12).

When finished with rendering, change the path to another folder (I created a second one and called it 'openGL').

Press the OpenGL render animation button (the one next to OpenGL render button).

You have now two rendered image sequences in two folders. Set up the nodes as pictured below. Instead of adding Image nodes, add two Image Sequence ones (Shift+A-->Input-->Image Sequence). Load the rendered pictures for each of them.

With setup like this go once again to the Output panel, click on the file directory browser and create a new folder for the final animation. Change the file format to for example AVI Raw. Render your scene once again using F12 button.

This has the disadvantage that you must render the entire image, only to crop off half of it, thus doubling rendertimes.

I would not say it's doubling the rendertimes, since OpenGL rendering is super fast (especially for scenes with no materials/textures). However you're right- that isn't a perfect method. I'm still thinking about doing it in a better/faster way. Maybe'll post another answer soon :).

You're right, it won't double the OpenGL rendertime, but it will for the normal render (almost).  I'm working on a way to do it with render borders, should be done in a few minutes.

Good point. A trick with overlaying half of the full render over the OpenGL one (as you said in your comment) will surely reduce the rendertime. Waiting for your answer.

I would do this by using a render border to render only half the image, then overlaying it onto an OpenGL render.
[
First set the render border to render only one half of the camera under Outliner (set to Datablocks) > Scenes > [Scene Name] > Render Data.  To render just the right half I set the Border Minimum X to 0.5.

Then name your output file to something like ..._render_ and render out the image sequence as .PNGs.
Next rename your output file to something like ..._OpenGL_.  Then (making sure you are in the camera view with Numpad 0) render as an OpenGL animation from the 3D view footer or Info Header > Render > OpenGL Render Animation.

Now go the the Video Sequence Editor (VSE) and use Add > Image to import the two image sequences (one sequence at a time).  Place the ..._render_... one above the ..._OpenGL_... one.

Lastly, set the Blend on the top strip to Alpha Over under N toolbar > Edit Strip.

Now you're ready to change the output filename to something like ..._split_ and render normally with F12.

Working on compressing the final render gif...


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Boolean modifiers are not working correctly on this mesh
I have two meshes, labeled A and B:

I want to subtract B from A, so that there is a "dent" in A where it intersects B.
This should be easy, but I've tried every Boolean modifier and none of them work. There are no other modifier on A or B.  I know Booleans work because I made the hole in A by subtracting a torus from it.
But I can't figure out how to subtract B. Everything I've tried has failed.
When I add a Difference modifier to A and target it on B, all of A disappears, except for the tube.
What am I missing?

A image containing different viewpoints would clarify.  I suggest quad view.  Try to show the open closed topology of your mesh.  Would both the owner of the modifier and the target hold fluid as a closed container?  A = owner. B = target.

Make sure you are inspecting your results correctly to know if the modifier worked correctly.  Use multiple colors to inspect.  All gray may create more work for you.  In the outliner window turn off and on the eye icon.  The eye icon affects 3D Viewport visibility for inspection.

Image above shows placement of unclosed hemisphere and modified cube. Corners have red balls for visibility discussion below.

In the image above the hemisphere is not really closed yet we played nicely and got the results we wanted as per the OP question.

In the image above we moved the blue hemisphere into a [exotic] position and we see [exotic] case where the boolean modified cube and hemisphere have coincident surfaces. The term [exotic] is yet to be defined.  Difficult to see resulting Cube. Most of the Cube has disappeared.  You can witness this interactively by moving the hemisphere left and right.

In the image above we see the surface remaining of the cube because the visibility of the hemisphere in blue has been set to false with the outliner window eye icon.  You may or may not want this type of result. Yes it is a feature.
If your hemisphere is not closed it can cause the disappearing act.  Use a fresh full sphere to compare. A closed sphere can be shaped into a well modeled closed nice hemisphere without deleting any vertices.  The open hemisphere can cause a thin surface to be in the same location as the hemisphere and visually hidden if we are too casual in inspection effort.  The boolean modifier may even try to make logically close a surface for you, but it is not wise to count on those intricacies. The boolean modifier may have complex behavior so you may find life easier if you do not create exotic cases.
Make sure both objects are closed volumes. Water Tight in loose terms.
Make your objects are temporarily closed if necessary. Perhaps the requirement of closed volume can be relaxed yet I problems occur close the meshes water tight.
Try 2 closed objects such as sphere and a cube.  They are closed already when unedited.  Water Tight in loose terms.  Try the Boolean Subtract Modifier.  This is to compare successful operations to unsuccessful ones.
Apply the modifier.  Move the modified object to a new location to inspect or hide the target of the modifier.
Superstitious.  I recently had to select the wrong type of Boolean to achieve the results I wanted.  I had to select [intersect] but logically I would choose [union].  Troubling.  I hope you do not have to do the same.

This worked; object B (the hemisphere) had a tiny hole in it I didn't notice before. I fixed the hole, and now the modifier works correctly (I used Difference).


text:
Can ultra-low-res textures cause problems while rendering?
This is a strange question, so comment if it's unclear.
I'm making a low-poly piece of art, where many of my objects will have only a single flat color (a cube that's all green, for example).
It seems that I should be able to use a very small texture for each object (the green cube could use just a single green pixel as its texture, for example).
I want to know if this will cause any problems. Should I use 16x16 or 32x32 textures, even though they provide more resolution than I actually need?
I am using the Blender internal render engine, though I also plan to export to Unity for a game project.

What render engine are you using?  I don't see any way it could cause problems for Cycles.  But if you have something that is all one color why do you even need a texture for it?

A lot of the objects are made by merging several single-color objects together into one, multi-color object. Can I do that without textures?

Sure, you can have multiple materials on one object.

Possible duplicate of How can I keep low resolution textures pixelated?

@HATMAN I don't see how that's a duplicate.  That's talking about color interpolation on scaled up low res textures, this is asking if there are problems with using very small textures.

Yes, having a low res texture can cause issues, but they can be prevented. Here is an example:
This is the texture I will be using in the example, which is 16x16 pixels:

If we import this into Blender we notice that the pixels are all smoothed and the detail is completely lost. This is because the interpolation is set to Linear, which will fade from the color of one vertex to the next using a linear gradient:

Switching this to Closest brings back all the detail and makes the image remain sharp:

In your particular example, as long as this is enabled, you can go down to a 1 pixel size without any issues.

I don't think you experience this effect if the texture is a solid color.

@PGmath I was under the impression they wanted to use 1 texture to define all the colors


text:
Why the displacement option in the material panel is missing?
I have seen this option (in displacement - bump only) in a youtube video but I can't find it under my settings panel:

Specific title, preferably a question please. Also consider to accept Robert's answer. How this site works: https://blender.stackexchange.com/tour

The Settings panel from your first screenshot is from the Cycles render engine. The second screenshot shows a project where Eevee is the current render engine.
The render engine can be changed in the Render Properties tab.


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Node Wrangler -- 'ShaderNodeBsdfPrincipled' AttributeError
I ran into a problem while using Node Wrangler.When I try to use the 'Add Principled Setup' option in the Node Wrangler menu and select the desired texture/PBR material files blender gives an error:
Traceback (most recent call last):
  File "C:\Program Files\Blender Foundation\Blender 2.81\2.81\scripts\addons\node_wrangler.py", line 2689, in execute
    if not active_node.bl_idname == 'ShaderNodeBsdfPrincipled':
AttributeError: 'NoneType' object has no attribute 'bl_idname'

location: <unknown location>:-1

Can anyone help me with this?

I had the same problem. Try selecting the Principled BSDF node before trying to import your materials, that fixed it for me

If that's still in 2.82a, please file a bug report (Help > Report a Bug).


text:
How to add edge between two vertices?
How do I add edge and one vertex between two vertices in Blender 2.8?   I put a red dot where I'd like to have the new vertex:

To make an edge between two vertices press F. If the vertices are on opposite sides of a face you can instead use J (for join).
To add a vertex, select the edge. Use Subdivide from the Edge menu.
To slide the vertex along the edge double press G.


text:
Menu list keeps on growing every time I debug my Operator script
This is a question about the process of developing an addon rather than a specific error in the script.
I'm creating an Operator that I want to show up in the UV Unwrap menu.  I'm editing the script in the Scripting tab and every time I want to try the latest version of my code, I press the little arrow button to run my script. Unfortunately, every time I do a new entry is added to my menu list, so over a programming session my menu quickly fills up with lots of identical entries to run my operator.  I just want a single menu entry.  I thought my operators unregister() method would take care of this, but it does not seem to.
What would be a better workflow to develop my addon?
import bpy
from bpy.props import FloatProperty

class UnwrapWorldUvOperator(bpy.types.Operator):
    bl_idname = "uv.unwrap_world_space"
    bl_label = "Unwrap World Space Operator"
    bl_options = {'REGISTER', 'UNDO'}

    scale: FloatProperty()

    @classmethod
    def poll(cls, context):
        obj = context.active_object
        return obj and obj.type == 'MESH' and obj.mode == 'EDIT'

    def execute(self, context):
        print (self.bl_idname)
        return {'FINISHED'}

def menu_func(self, context):
    self.layout.operator("uv.unwrap_world_space")

def register():
    bpy.utils.register_class(UnwrapWorldUvOperator)
    bpy.types.VIEW3D_MT_uv_map.prepend(menu_func)

def unregister():
    bpy.utils.unregister_class(UnwrapWorldUvOperator)
    bpy.types.VIEW3D_MT_uv_map.remove(menu_func)

if __name__ == "__main__":
    register()

unregister doesn't get called automatically in the scripting editor

Does this answer your question? Adding Custom Menu "Run Script" Button Causes Duplicate

You can test whether menu_func is already part of _draw_funcs list and if so, do not prepend:
def register():
    bpy.utils.register_class(CUSTOM_OT_operator)

    if hasattr(bpy.types.VIEW3D_MT_uv_map.draw, '_draw_funcs'):
        if menu_func.__name__ not in (f.__name__ for f in bpy.types.VIEW3D_MT_uv_map.draw._draw_funcs):
            bpy.types.VIEW3D_MT_uv_map.prepend(menu_func)
    else:
        bpy.types.VIEW3D_MT_uv_map.prepend(menu_func)

def unregister():
    bpy.utils.unregister_class(CUSTOM_OT_operator)
    bpy.types.VIEW3D_MT_uv_map.remove(menu_func)

if __name__ == "__main__":
    register()

You can some how "try" to unregister it before register in main function.
And also keep track of the last registered object, a quick way is set an attribute in bpy:
if __name__ == "__main__":
    if not getattr(bpy,'temp_addons', None):
        setattr(bpy,'temp_addons',[])
    try:
        add_list = getattr(bpy,'temp_addons', [])
        while add_list:
            old_addon = add_list.pop()
            bpy.types.VIEW3D_MT_mesh_add.remove(old_addon)  # Your addon
        unregister()
    except:
        pass
    register()
    getattr(bpy,'temp_addons', []).append(add_object_button)  #Your addon
    print(bpy.temp_addons)

Another better way might be define register() and unregister() more carefully, return object used inside that addon when using main function.

That is not doing anything when I run it.  Also, 'catch' should be 'except' in Python.

You're right, I forgot that menu is using object rather than bl_idname, then you might need to manually keep track of your menu object in some global place


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Python Scripting Help - Add-on to auto swap materials working but with one flaw! Unrecognized materials given blank material slot
I need some help. I do not know how to code, though I’m starting to learn a bit. I have been using chat gpt to assist me in creating a custom tool as an add-on. I have gotten it to work most of the way but hit a wall.
We have made a digital library of products, all with many materials assigned to many many objects to use as assets. They were created at real to world scale using mostly procedural materials. We want to get back to standard blender scale, but the materials do not properly scale. So we created new materials of the same name at the proper scale. As we have hundreds of these I wanted to automate the swapping of the materials on these files. I’m almost there.
So far I have gotten it to

successfully read materials from a specified .blend file as the new material library
check the material names that match the names of the selected objects, while ignoring any suffixes like .001, .002, etc which happen when we add the same material to the scene more than once.
Successfully swap the materials in the scene with the materials from the material path specified.

The problem comes when there is a material NOT in the specified material library. I want those to be ignored and left in place on the objects and only swap the materials recognized from the library file. However it is currently changing unrecognized materials into a blank slot.
I just want unrecognized materials to be ignored and left in place and the rest of the script to work as is. The robots couldn’t help. Can any one read the script and see what is going wrong? I appreciate your help!!!
Here is the script….
bl_info = {
  "name": "Swap Material Add-on",
  "author": "Dave Schwalbach",
  "version": (1, 0),
  "blender": (3, 0, 0),
  "description": "Swaps materials of selected objects from a library",
  "category": "Object",
}

class SwapMaterialFromFile(bpy.types.Operator):
  bl_idname = "object.swap_material_from_file"
  bl_label = "Swap Material from File"

  # Specific file path to the Blender file containing materials
  filepath: bpy.props.StringProperty(
    name="Swap Material File Path",
    description="Path to the Blender file containing materials",
    default="",
    maxlen=1024
  )

  @classmethod
  def poll(cls, context):
    return any(obj.type == 'MESH' for obj in context.view_layer.objects.selected)

  def execute(self, context):
    # Store the current scene
    current_scene = context.scene

    # Iterate through selected objects
    for obj in context.view_layer.objects.selected:
      for slot in obj.material_slots:
        # Check if the material is not None and not "Silver Label"
        if slot.material and slot.material.name != "Silver Label":
          try:
            # Check if the material name exists in the loaded file
            material_name = slot.material.name.split('.')[0] # Ignore suffixes

            # Load the material file
            with bpy.data.libraries.load(self.filepath) as (data_from, data_to):
              data_to.materials = [material_name]

            # Check if the material was recognized
            if data_to.materials:
              # Assign the material from the loaded file
              slot.material = data_to.materials[0]
              print(f"Swapped material: {material_name} in object: {obj.name}")
            else:
              # Print a warning if the material was not found
              print(f"Material not found in the loaded file: {material_name} in object: {obj.name}")

          except (IndexError, AttributeError) as e:
            print(f"Error: {e}")
            # Handle IndexError (no materials in the loaded file) and AttributeError (material_name not found)
          except Exception as e:
            print(f"Unexpected error: {e}")
            # Handle unexpected errors

    # Set the active scene back to the original scene
    context.window.scene = current_scene

    return {'FINISHED'}

# Panel definition with argument passing
class SwapMaterialPanel(bpy.types.Panel):
  bl_idname = "PANEL_PT_swap_material"
  bl_label = "Swap Material"
  bl_space_type = 'VIEW_3D'
  bl_region_type = 'UI'
  bl_category = "Tool"

  # Define the filepath property within the class
  swap_material_from_file_filepath: bpy.props.StringProperty(
    name="Swap Material File Path",
    description="Path to the Blender file containing materials",
    default="X:\\AdvEng\\Industrial Design Documents\\Design Assets\\Blender Design Assets\\Asset Library\\Scaled Material Trial\\Materials Scaled Down Trial.blend",
    maxlen=1024
  )

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

    # Use the filepath value in the label
    layout.label(text="Swap Material File: " + context.scene.swap_material_from_file_filepath, icon='INFO')

    # Add the "Execute" button
    layout.operator(SwapMaterialFromFile.bl_idname, text="Execute")

# Register add-on classes
def register():
  bpy.utils.register_class(SwapMaterialFromFile)
  bpy.utils.register_class(SwapMaterialPanel)

  # Register the property for the panel
  bpy.types.Scene.swap_material_from_file_filepath = bpy.props.StringProperty(
    name="Swap Material File Path",
    description="Temporary storage for file path during use.",
    default="",
    maxlen=1024
  )

def unregister():
  bpy.utils.unregister_class(SwapMaterialPanel)
  bpy.utils.unregister_class(SwapMaterialFromFile)

  # Unregister the property
  del bpy.types.Scene.swap_material_from_file_filepath

if __name__ == "__main__":
  register()

Please note, I have omitted the file path for privacy but is there in the script I am using.
Thank you in advance!!!

When there is no material with the name material_name data_to.materials contains [None] which is a truthy value such as bool([None]) == True
When you use slot.material = [None][0] which is slot.material = None you remove the material from the slot.

Hey, thanks for taking the time to answer. I will look into that this evening! Thank you!


text:
How set the default scaling factor for importing and exporting to be equivalent to real world scale? How to change the defaults?
Ok, this doesn't seem to be a new problem, but I am looking for a new solution. I use blender for both printing in the real world and visualizing and simulating. For a long time I did like everyone else and set the units to Millimeters and then scene scale to .001. This works to get things in and out at the right scale, however it screws up everything else blender does. Physics don't work, camera properties are wrong, lighting doesn't work as expecting and so on.
So, I want to work to Blender scale...1 unit = 1 millimeter. I don't want to change the scale factor so all the systems in blender work as normal, but when getting objects in and out of blender I want them to be the correct scale. I would like to set the default scale factor to export at 1000 and import at .001, so when it gets inside blender or outside of blender it is correct. Many people are working on this so I don't want everyone to have to remember when to scale what by what, and instead just have these values be the default.
I have tried to use chatgpt to help me code an add on to do this but blender's default scaling of 1.0 on import or export persists. How can I fix this?? Thanks in advance!

Hello, what format are you importing from / exporting to ?

Mostly exporting to STL but also OBJ, FBX for export. For import all those same file types, and very often STEP. We use Stepper add-on for importing STEP files.


text:
Crash when setting a vertex position using Python
I am a developer of a physics simulation engine, and I want to connect it to Blender, so I can render simulations in Blender. The physics engine simulates soft bodies. Deformation of meshes occurs, usually at each time step.
I use Blender 3.6.4 on Windows.
The approach I took is the following:

Just after the first time step of the simulation, I create a new collection, with a new object, with a new mesh using the data I just computed from the simulation:

new_mesh = bpy.data.meshes.new(object_name)
new_mesh.clear_geometry()

new_mesh.from_pydata(object_data["position"], {}, object_data["faces"])
new_mesh.update()

new_object = bpy.data.objects.new(object_name, new_mesh)
collection.objects.link(new_object)

After the following time steps, I update the vertices and insert a keyframe on them:

obj = collection.objects[object_name]

pos_id = 0
for v in object_data["position"]:
    if len(obj.data.vertices) > pos_id:
        obj.data.vertices[pos_id].co = v
        obj.data.vertices[pos_id].keyframe_insert("co", frame=iteration)
        pos_id = pos_id + 1

What do you think about the approach? Can you suggest a more appropriate strategy?
In the meantime, the current approach makes Blender crash randomly: not always the same time step, not always the same stack trace. However, I often have the crash happening on obj.data.vertices[pos_id].co = v, leading (sometimes) to the following stack trace:
blender.exe         :0x00007FF648F1C600  blender::deg::`anonymous namespace'::deg_graph_node_tag_zero
blender.exe         :0x00007FF648F1CC20  blender::deg::graph_id_tag_update
blender.exe         :0x00007FF648F1D700  DEG_id_tag_update
blender.exe         :0x00007FF6491C1280  rna_Mesh_update_positions_tag
blender.exe         :0x00007FF6490FBC40  rna_property_update
blender.exe         :0x00007FF649107340  RNA_property_update

Any idea how to solve this crash?
Thanks

Hello ! AFAIK obj.data.vertices[pos_id].co is readonly so I'm not surprised you have a crash when you try to assign it. The most straightforward and fast way to set a mesh is to use from_pydata. Instead of trying to change the mesh directly and iteratively, make the change to the input data and run from_pydata once at the end

@Gorgious I must be missing something, I have no doubt you've set a coordinate of a vertex many times in the past, both in bmesh and normal mesh data, so how would the co be read-only? As in, you can't replace the vector with another?

@MarkusvonBroady you're right, I didn't remember it well. Sorry :) Found this while looking it up https://blender.stackexchange.com/questions/121292/how-can-i-reassign-or-move-vertexes-of-a-vertex-group My next best guess is that there is a discrepancy between the input list and the vertex size

Thanks for the suggestion. I tried with from_pydata, but I still have the crash. I tried to reduce the problem by removing the keyframe management, by removing the faces, by removing the collection hierarchy. Still the random crash. I also verified the validity of the data

My script was also crashing after hundreds of frames, never investigated why… Maybe there's a bug in Blender, or it was some racing condition…


text:
Light bending or custom rendering engine?
I want to create a short animation of the sun/moon rising and setting.
However I want to include some custom parameters to allow for the bending of light.
To elaborate, I am not talking about refraction here - instead I am talking about a competely new capability of light to bend in an arc that starts horizontal near the ground and gradually ascends into the sky (like an exponential curve). So basically I want to be able to describe how light should travel - not in a straight line but in an arc.
Is there a way that this can be done in blender or do I need custom work done?
If custom work is needed, who should I get in touch with for it?
Thanks

Can you include an image of something similar to your artistic vision?  Is there some measure of physical correctness?

Atomic, I do not have something to show you. As for physical correctness, we are taught that light travels in straight lines. Physical tests done recently show that light does not travel in straight lines but in actuality bends towards the vertical/upwards (noticable around the kilometer mark). I was just wandering if current engines support this and if not how we can get an engine to support this.

@conanDrum I would like to know where in the world is taught that light travels in straight lines.. Even in elementary kids know about gravity and what it does to light.

lol... Actully we are taught that it is affected by gravity but we can neglect it. Alll physics in school disregards this bending in our atmosphere. That's what I mean... I need an engine that allows for light manipulation, just like the one used for interstellar as mentioned below by Jerryno. (If I need to simulate a black hole for example)

Nope Cycles cannot bend light in arc nor Blender Internal. Only the renderer Interstellar was rendered in is capable of it as far as I know.
You can bend light with multiple planes with refraction shaders though.
Or you can code your own renderer.

The renderer for interstellar.... is it a rendering engine that can be used with blender? I want to bend light not to refract it because refracting white light will separate into a rainbow. The bending I want will only affect the perceived position of objects when viewed... not their colours.

@conanDrum no, refracting cannot separate single white beam into rainbow in Cycles. Cycles does not support dispersion. Interstellar renderer is not compatible with Blender.

Thanks Jerryno. So my only options are Cycles or a customization on the blender engine?

@conanDrum Yes, I would fake the effect with multiple invisible refraction planes - that would be the most simple approach to get the visual. You can also customize blender but that's a lot of coding to do.


text:
How do i create a Doodle art animation in Blender?
I would like to create a Doodle art using blender and to give animations to the individual doodles. i want to a have Individual Doodle character to be animated...just like in relative manner.Please help me with this..

For doodle art see this: http://blender.stackexchange.com/questions/35591/how-could-i-create-a-3-dimensional-scribble-or-doodle

Thanks,But i want to a have Individual Doodle character to  be animated...just like in relative manner......

For animating see this http://blender.stackexchange.com/questions/3171/how-to-animate-multiple-lines

Let me try it.....keep up the good work Sir


text:
cycle units measurement through hotkey is it possible?
i find imperial is much easy or convenient to setup with camera distance from
object a to b and eye level height
i want to set a hotkey that cycle through units ( metric , imperial )
hitting same hotkey instead of manually going to tab and click the desired units button
i tried to use wm.context_toggle_enum and type the following attributes but gives error
context.scene.system , scene.system , UnitSettings.system , data.scene , data.scene.system
or do i need a custom .py script in order to achieve the cycling of metric and imperial units
thank you for answer

Can't you just right-click on the measurement setting in the Properties panel and assign a hotkey?

The path to use for the context Attribute is
scene.unit_settings.system

Where you find a class name of UnitSettings is shown with it's name in CamelCase, you will often find a corresponding property that represents it will use the form unit_settings with all lowercase and underscore separating words.


text:
automatically detects 3D view by selecting one face mesh

hi instead of using numpad ( front / back /left / right / bottom / top
  ) to locate the desired view , is there a operation in blender that
  automatically detects/change the view by just selecting a face of a mesh object

reason im looking for this command

less hotkeys ( 1 only )
Quickly locate the view
Avoid confusion ( sometimes i tend be confuse whether if its left/right or front back of the mesh which leads to slowdown of workflow )

thank you for answers

You can open one more 3D View editor, make it really small and look at it just to navigate your mesh. Also to save  time for navigation it's useful to look at the mini-axes located in the bottom left corner. And probably new script should be written to make the view behave like you ask when selecting a face.

see this http://blender.stackexchange.com/questions/15045/how-do-i-align-the-viewport-to-a-face-normal

hi thank you for quick reply about http://blender.stackexchange.com/questions/15045/how-do-i-align-the-viewport-to-a-face-normal but it gives me this result http://imgur.com/gxxABKN .. is there a way it will not rotate the view ?

to add ..  i want it to remain at default view like in quad view box ( frontal view + ortho ) where there is no rotation ..thank you

in the quad view mode the view can be aligned only in the upper right view (perspective)... the other views are fixed by definition...  I don't know anymore what you want...