nodebpy 520.5.2

Build nodes trees in Blender more elegantly with code

nodebpy

Build node trees in Blender more elegantly with Python code. Geometry Nodes, Shader Nodes and Compositor nodes are all fully supported, with type hints and IDE auto-completion throughout.

pip install nodebpy

A text-based version of nodes should bring the convenience of writing code with IDE auto-completion, type hinting, with overall compactness and readability, while staying as close as possible to what building a node tree via the GUI feels like.

from nodebpy import geometry as g

with g.tree("AnotherTree", collapse=True) as tree:
    rotation = (
        g.RandomValue.vector(min=-1, seed=2)
        >> g.AlignRotationToVector()
        >> g.RotateRotation(rotate_by=g.AxisAngleToRotation(angle=0.3))
    )

    _ = (
        tree.inputs.integer("Count", 10)
        >> g.Points(position=g.RandomValue.vector(min=-1))
        >> g.InstanceOnPoints(instance=g.Cube(), rotation=rotation)
        >> g.SetPosition(
            position=g.Position() * 2.0 + (0, 0.2, 0.3),
            offset=(0, 0, 0.1),
        )
        >> g.RealizeInstances()
        >> g.InstanceOnPoints(g.Cube(), instance=...)
        >> tree.outputs.geometry("Instances")
    )

• Every node is a typed class named after the node it creates — 'Random Value' becomes g.RandomValue() — and node subtypes are class methods: g.RandomValue.vector().
• Trees are built inside a with g.tree(...): context; instantiating a node class adds it to the current tree, and the tree's interface is declared with tree.inputs.* / tree.outputs.*.
• Nodes are linked with the >> operator, which picks the most compatible socket pair automatically (much like Node Wrangler's Alt + Right Click drag) — or address sockets explicitly through the .i.* / .o.* accessors.
• Python's arithmetic, comparison and boolean operators create the matching Math / VectorMath / Compare / BooleanMath nodes: g.Value(1.0) * 2 + (0, 0, 1).
• Existing node trees — including ones wired up by hand in the GUI — can be exported back to nodebpy source with to_python().

Documentation

Guides and the full node reference live at bradyajohnston.github.io/nodebpy:

• Writing node trees — adding, linking and organising nodes
• Math operators — arithmetic, comparison and boolean expressions as nodes
• Node API design — sockets, accessors, enum options and class methods
• Custom node groups and asset node groups — reusable groups as Python classes
• Nodes to code — turn existing trees back into nodebpy code
• Using nodebpy in your add-on — installation, bundling and the Blender-tracking versioning scheme
• Comparisons — how the API relates to geometry-script, geonodes, NodeToPython and TreeClipper

Like databpy, this project started as an internal tool inside molecularnodes before being broken out into its own robustly typed and tested package.

Contributing

Development setup, running the tests and regenerating the node classes (most of src/nodebpy/nodes/ is auto-generated by the gen/ package) are covered in CONTRIBUTING.md.