What is the Python script to create nodes?

Question

Is there a way to convert nodes (or nodes group) into Python script automatically?

If not what is the python script to:

create a node and set his position
attach a node to another and choose the input and output (and found the name of the input/output script)
create a group
choose if we want to create the node in the compositor or for a cycles shader
mute a node

related: http://blender.stackexchange.com/questions/5668/add-nodes-to-material-with-python — TLousky, Jun 16 '16 at 15:30
I would say that each of those bullet points should be separate questions, some of which have already been answered on the site. — Ray Mairlot, Jun 16 '16 at 15:31
All the answers are here: http://blender.stackexchange.com/questions/23436/control-cycles-material-nodes-and-material-properties-in-python/23446 (for Cycles nodes) and here: http://blender.stackexchange.com/questions/19500/controling-compositor-by-python/19501 (for Compositor nodes). You mute a node by toggling it's node.mute property. Please read the python API documentation. — Jaroslav Jerryno Novotny, Jun 17 '16 at 05:42
Shader node group is just enother node type of ShaderNodeGroup and you access it's nodes like this: node.node_tree.nodes (through it's own node_tree property). Here is the documentation: https://www.blender.org/api/blender_python_api_2_77_1/bpy.types.ShaderNodeGroup.html#bpy.types.ShaderNodeGroup — Jaroslav Jerryno Novotny, Jun 17 '16 at 05:47
You can also use Python nodes as in here: https://blender.stackexchange.com/questions/67487/cycles-materials-math-node-with-more-than-two-inputs/99003/ — Secrop, Nov 05 '18 at 10:33

BrendanParmer · Answer 1 · 2023-08-03T02:50:22.373

There's not an out-of-the-box, native way to do this, at least as of the current version (Blender 3.6). However, you can write a script using the Python API.

Creating a node: https://docs.blender.org/api/current/bpy.types.NodeTree.html#bpy.types.NodeTree.nodes
- ex. my_node = my_node_tree.nodes.new('ShaderNodeSeparateXYZ')
Setting a node's position: https://docs.blender.org/api/current/bpy.types.Node.html#bpy.types.Node.location
- ex. my_node.location = (100, 200)
Attaching nodes: https://docs.blender.org/api/current/bpy.types.NodeTree.html#bpy.types.NodeTree.links
- ex. my_node_tree.links.new(my_node.outputs[1], my_node_2.inputs[3])
- To get the sockets, you can also reference the inputs/outputs by name (my_node.outputs["X"]), but I've found you sometimes run into name conflicts with this approach, so I don't recommend it. Using the socket's index guarantees you don't get any collisions, but these often need to be found programmatically. The sockets can be hidden either by a node group creator or by a node setting changing the visible inputs and outputs, so the first visible output socket doesn't necessarily correspond to my_node.outputs[0].
Creating a group: For this, you want to create a new node of the appropriate type ('GeometryNodeGroup', 'ShaderNodeGroup', or 'CompositorNodeGroup'), and then set its node_tree attribute with the one you want. You'll likely want to set up inputs and outputs for the group, as well, which you can find some documentation here https://docs.blender.org/api/current/bpy.types.NodeTree.html#bpy.types.NodeTree.inputs.
- ex.
```
my_group_node = my_node_tree.nodes.new("ShaderNodeGroup")
my_group_node.node_tree = bpy.data.node_groups.new(type="ShaderNodeTree", name="Shader Node Tree 2")
my_group_node.node_tree.inputs.new("NodeSocketInt", "An Integer Input")
my_group_node.node_tree.outputs.new("NodeSocketColor", "A Color Output")
```
Muting: https://docs.blender.org/api/current/bpy.types.Node.html#bpy.types.Node.mute
- ex. my_node.mute = True

As for a solution that does all this automatically, I've created an open source add-on that does all this for Geometry Nodes and Shader Nodes for Blender 3.0-3.6, with work in progress for Compositing Nodes.

https://github.com/BrendanParmer/NodeToPython

You're right, I was trying to futureproof the response in case something were to change after v3.6. As far as I'm aware this hasn't ever been a feature that comes with Blender — BrendanParmer, Aug 03 '23 at 02:44
Alright, all good then. Thank you for the answer and the addon. Congrats for the 100 stars ! ;) — Gorgious, Aug 03 '23 at 09:52

score -1 · Answer 2 · answered Nov 05 '18 at 08:35

Here is a repo that does exactly what you want. It has a ready-to-run python script that can be run from the command line in the background without opening the blender GUI. It creates a water material on a surface mesh for a convecting bubble - this is done with 2 different shaders and mixing them using a mixer shader. The script loops through the different files and renders the images as jpeg. The images are also there in the repo. Just clone the repo and run the command given in the README file in the terminal. This scripting was done with Blender v2.78.

https://github.com/nataraj2/BlenderScripting

What is the Python script to create nodes?

2 Answers2