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pythonsocketsnodesblender

Custom node sockets and CustomSocketInterface in Blender Addon

I'm using Blender 2.79 but Blender 2.8+ likely operates the same

Example for custom nodes

Initially, I was using NodeSocket subclasses as custom sockets, but eventually I got this error AttributeError: 'NodeSocketInterface' object has no attribute 'draw_color'. Others also had issues with default_value not being present in NodeSocketInterface.

How do I use this NodeSocketInterface class?

Solution

  • This is due to not registering a NodeSocketInterface. When registering the NodeSocket subclass, a dummy NodeSocketInterface without the required methods/properties is automatically created.

    I wrote the following code based on understanding the Blender source code, and it works for registering a CustomSocketInterface associated to a CustomSocket:

    # Blender 2.79
# (bl_idname defaults to class names if not set)

class CustomSocketInterface(bpy.types.NodeSocketInterface):
    bl_socket_idname = 'CustomSocket' # required, Blender will complain if it is missing
    # those are (at least) used under Interface in N-menu in
    # node editor when viewing a node group, for input and output sockets
    def draw(self, context, layout):
        pass
    def draw_color(self, context):
        return (0,1,1,1)

class CustomSocket(bpy.types.NodeSocket):
    def draw(self, context, layout, node, text):
        pass
    def draw_color(self, context, node):
        return (0,1,1,1)
...
# register (didn't try but order should matter)
    bpy.utils.register_class(CustomSocketInterface)
    bpy.utils.register_class(CustomSocket)