blender-syntax-nodes

Quick Reference

Critical Warnings

NEVER use node_group.inputs.new() or node_group.outputs.new() in Blender 4.0+ — these are removed. ALWAYS use node_group.interface.new_socket().

NEVER access node sockets by index (node.inputs[0]) — indices shift when sockets are added or removed. ALWAYS use node.inputs["Name"].

NEVER use scene.node_tree for compositor access in Blender 5.0+ — it is removed. ALWAYS use scene.compositing_node_group.

NEVER set modifier inputs by socket name (modifier["Width"]) — modifier inputs use auto-generated identifiers (Socket_N). ALWAYS iterate interface.items_tree to find the correct identifier.

NEVER modify node trees during an active render — race conditions with the render thread cause crashes. ALWAYS modify nodes before render starts.

Node Tree Architecture

All node systems in Blender share this architecture: