Questions tagged [development]

For coding questions about Blender development, including addon or script development with the Python API. Does not include general programming questions, non blender specific tasks or errors, nor compilation of Blender binaries.

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UV Map editing with python

I have been trying to figure out the best way to make a material for Minecraft blocks inside of my addon. Excluding special cases, a Minecraft block is a 1-meter cube that has an image texture of ...
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1 answer
22 views

Changing order of props in input dialog (addon development)

I'm creating addon that adds couple of objects to the scene and I need to control input arguments. Figured out that the best way for me (with almost zero experience with python but 25+ years in other ...
1 vote
1 answer
51 views

Who owns Blender? [closed]

Blender is an program that has been growing over the past few years through the work of the community. The development of the program is to my understanding largely community based. Although some of ...
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0 answers
29 views

bpy not valid Win32 application error

I've built Blender as a python module on my windows 10 64X bit pc. I've then uploaded the 3.2 folder, bpy.pyd, and all .dll files to a github repo. After I download these files onto my remote windows ...
1 vote
0 answers
119 views

How to convert Blender as a Python module into an easily downloadable package?

I have successfully converted Blender 3.2 into a python module on Windows 10 and can import it into my Python 3.10 scripts and run bpy commands. As described in Building Blender as Python Module on ...
3 votes
3 answers
294 views

How do you work with a GitHub repo inside Blender.app/.exe? [duplicate]

What is a good method to update a GitHub repository without manually copy/pasting the entire repo into the Blender addons folder when developing Blender add-ons?
0 votes
0 answers
93 views

Group Custom Node Tree

I am using the built-in python script template 'Custom Nodes' to create a custom node tree, and when I have finished most of the works and try to group my nodes, I find the menu item 'Group' is ...
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32 views

Can a new Node for Compositor be implemented as an add-on? (vs. modifying Blender code)

My goal is to add a new Node to Compositor. Currently it does nothing but I can already add it from the Shift+A menu... wowewow, great success! Is it be possible to deliver the new Node as an add-on, ...
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60 views

Blender Install crashes at end and window pops up The specified path K:\Users\...\AppData\Roaming\Micosoft|' is unavailable

When trying to install the program it crashes at the end with a popup message blender Setup The specified path 'K:\Users...\AppData\Roaming\Microsoft' is unavailable.
1 vote
1 answer
64 views

Different result between applying matrix to mesh and applying matrix to object

...
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0 answers
131 views

Override context (selected objects) of bpy.ops.view3d.localview

I want to move parent along with children to local view. Some children have hide_select=True. I tried doing something like this to no avail: ...
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1 vote
0 answers
40 views

Custom Nodes: How to make something happen when node is added

I'm creating a custom node tree and custom nodes following the blender script templates - https://github.com/blender/blender/blob/master/release/scripts/templates_py/custom_nodes.py The template does ...
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0 votes
1 answer
69 views

MixRGB vs math performance for single/greyscale values

I would like to know if MixRGB still calculates the three color channels if the input is a number or grayscale value. I am aware the result is the same either way but, this matters for simplifying and ...
1 vote
1 answer
96 views

Dynamic Paint displacement use wrong normals if placed after deforming modifiers

I've been trying to use the displacement option from the Dynamic Paint physics modifier after an Armature modifier, but it seems that the normals used for the displacement direction are from the raw ...
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4 votes
2 answers
127 views

How can the linear-time cost of Blender's .children Python property be avoided in scenes with many objects?

While working on optimizing an add-on that creates/manages a large number of objects, I noticed that invocations of bpy_types.Object.children accounted for an ...
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1 vote
1 answer
270 views

How can I change the size of a modal operator popup dialog box?

I have a modal operator that invokes itself and is called from an AddonPreferences PT. I have been trying to scale_x without success. A row.scale_x works within the size of the entire modal, it is 3....
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1 vote
1 answer
106 views

Remove "Preferences:" label from AddonPreferences, no bl_label to " "?

I see no "bl_label" in "AddonPreferences" in the Blender API. One of the buttons in my AddonPreferences is "Preferences" and it would be nice to remove the default "...
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34 views

What areas of mathematics will help me in creating this add-on?

I want to create an add-on like this. It edits the selected edge, adds vertices to it ( as much as you need - the parameter will be adjusted ), creates the curvature we want. I want to make this add-...
1 vote
0 answers
322 views

Cannot import nested Python module when writing an add-on

I am working on my first add-on, though I am pretty experienced with Python having written multiple apps using Django. My project structure looks like this: ...
1 vote
0 answers
20 views

Info Node Eevee Integration [closed]

I am currently working on an integration for a length socket in the Hair Info node and got it working in cycles allready, but am currently struggling to find out where in the code the shader values ...
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3 votes
2 answers
157 views

Camera solving - what algorithm is used?

Note: this question is about how Blender is implemented, not how it's used. IIUC, Blender uses 8 points (or more) at two keyframes to calculate the position in space of the camera. What is the ...
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1 answer
143 views

Blender addon development [closed]

I have a hard modelling addon idea for blender. I have no coding experience and have no idea where to even start with learning coding or what I need to learn. It's an add on building on an existing ...
1 vote
0 answers
101 views

Blender Dev. Custom properties set hide or non editable

I was wondering if is a way to hide or set as non editable a custom property. In Phyton i can use: object[ label_property ] = value_property I need to said... ...
0 votes
2 answers
114 views

Menu list keeps on growing every time I debug my Operator script [duplicate]

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 ...
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2 votes
0 answers
75 views

Help me understand the viewport render pipeline with cycles

I am trying to understand the pipeline that creates a rendered image in the viewport with cycles from start to finish in the blender/cycles source code. A little bit of context (Skip if not interested)...
0 votes
1 answer
82 views

Git Flow when coding for blender

I am sry if this is the wrong place to ask this or if this has already been answered elsewhere but I couldn't find it. I am confused about the git workflow when coding for blender: When I clone the ...
1 vote
1 answer
256 views

Extending Sverchok - Development of new nodes in a separate addon

TL;DR: Is Sverchok designed to have their node list extended by third-party addons? If so, are there any formal templates to follow? I would like to play with the idea of developing new nodes for ...
2 votes
0 answers
68 views

Is there a way to insert an operator into a menu?

I've written an add-on for saving files, and I want to insert it into the file>save menu. But if I use ...
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1 vote
0 answers
43 views

Viewport with external application?

Is it possible to display/draw the viewport of Blender in an another application? eg. Run blender in the background to display the wireframe view of a Blender file within another app? (Sorry if this ...
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3 votes
0 answers
59 views

How to add my own SECOND splash screen

I want to add a second splash screen that will appear when I start blender and in which I can add my own text. This is necessary for my addon.
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1 vote
0 answers
1k views

How the Blender 3D 2.8x Graphical User Interface is Made?

I want to know all the processes, functioning, involved languages, examples of code, and URLs to official sites with updated information if possible. NOTE: I'm not a programmer. I just want to know ...
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0 votes
3 answers
632 views

Looking for Blender source code of version 2.79.7

Where can I find the source code, corresponding to this exact build 2.79.7 blender-2.79 e045fe53f1b0 ? - https://download.blender.org/release/Blender2.79/latest/
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1 vote
1 answer
429 views

Accessing Blender's DNA Mesh struct via as_pointer()

How can I access the actual structure of a Mesh datablock in memory using the value returned from bpy.types.Mesh.as_pointer() In 2.79 Blender there used to be a possibility to do that by just passing ...
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0 votes
0 answers
126 views

Connecting A Node Group Between Principled and Output Shaders With Python

I am aware I could do ...
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1 vote
1 answer
219 views

context.material.node_tree - context has no attribute to material?

I am trying to write an addon, I am making a node group that will be created with a single button however I have run into issues with these final lines: ...
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2 votes
1 answer
308 views

Query if modifier exists on listed objects [duplicate]

I'm new to Blender and the way it works with Python, so I still don't understand quite well the way the different commands work. But I wanna create a small tool where i can assign a modifier to a ...
2 votes
1 answer
48 views

How to remove the upper tabs from the UI?(i.e Layout, Modeling, Sculpting etc.)

I want to streamline the UI of Blender from the source, so I was wondering where I could find the code concerning those tabs because all of them are very overwhelming and I would prefer to either ...
1 vote
2 answers
320 views

How do I add an .obj file from a relative file location?

I need help adding an .obj file via scripting. I've tried using this line of code, but I'm having issues importing the obj file: ...
1 vote
0 answers
54 views

How do you go about solving a bug in Blender: language selector in python console

For example, based on: Purpose of the languages selector in the Python Console I am familiar with git and reporting a bug. But my question is: How do you go about solving such a bug? Blender uses C/...
1 vote
0 answers
52 views

Where is the core code that makes up Blender's ShapeKey? [closed]

I'm looking for the core C / C ++ code that makes up Blender's ShapeKey. I'm looking for Blender standard features, not add-ons. I know Blender is open source, but I'm an amateur about Blender. ...
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1 vote
0 answers
164 views

Equivalent of mesh.tessfaces.add, foreach_set in 2.8

I have the following code in an addon: ...
0 votes
0 answers
48 views

Why do Blender objects have one ShapeKey each?

I am using Maya and Maya has BlendShape. Maya's BlendShape is almost the same as Blender's ShapeKey. And, Maya's BlendShape can transform multiple objects with one node. However, Blender's ShapeKey ...
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0 votes
1 answer
72 views

Add-On Dev: Open external file with default program

I was planning to create some simple help-like text or HTML documents in a local folder of my add-on, and provide "help" buttons on the panels to allow the user to access them from each section that ...
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1 vote
0 answers
19 views

Add-on Dev: Label Tool-tips?

I have a list of 12 'elements', where several check-boxes will relate to each element. The best way I can think of to handle this type of situation is to draw the check-boxes without labels, then ...
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1 vote
0 answers
204 views

Blender Python: Fixed size list of elements?

I need 4 instances of a property group sub-class in my primary class, and I want to access them (main.sub[*].x) based on an enum or index. Here's a fictitious (and ...
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0 votes
0 answers
627 views

How can I detect when the active or selected object changes using Python?

Is it possible to detect changes in object and collection selections or activations (bpy.context.object/collection)? I'm most interested in detecting changes in the ...
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4 votes
0 answers
276 views

How to check if mouse is in View3D Window from modal operator (2.80)

In the context of a modal operator, I would like to perform an operation when the left mouse button is clicked in the VIEW_3D area, ...
2 votes
1 answer
1k views

Blender Python: Declare Property Group (on the stack?)

The questions keep coming, I know. I cannot find this simple answer anywhere. It may be because I'm not sure exactly how to phrase it in searches. Is it possible to declare a variable of a custom ...
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0 votes
1 answer
213 views

Blender Python: Property Description String Limit?

Is there a string length limit for the descriptions of properties? I assume there is. Does anyone know what that length is, and is there a safety mechanism to catch strings that are too long? ...
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3 votes
0 answers
161 views

Blender Python: Access Selected Collections?

How would I go about accessing the list of selected collections? It seems as though the selection state of collections is something specific to the Outliner? But I can't seem to find anything in the ...
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