Blender addon: Use Simplify F-Curves on any action visible in the graph editor.

action_simplify.py

import bpy
import curve_simplify

bl_info = {
    'name': 'Simplify Action',
    'author': 'Tamas Kemenczy',
    'version': (0, 1),
    'blender': (2, 91, 0),
    'description': 'Use Simplify F-Curves on any action visible in the graph editor.',
    'category': 'Add Curve',
}


def get_action(context=None):
    if not context:
        context = bpy.context
    for area in context.screen.areas:
        if area.type == 'GRAPH_EDITOR':
            for space in area.spaces:
                if space.type == 'DOPESHEET_EDITOR':
                    return space.action


class GRAPH_OT_simplify_action(bpy.types.Operator):
    bl_idname = 'graph.simplify_action'
    bl_label = 'Simplify Action'
    bl_description = ("Simplify selected Curves\n"
                      "Does not operate on short Splines (less than 3 points)")
    bl_options = {'REGISTER', 'UNDO'}

    error: bpy.props.FloatProperty(
        name="Error",
        description="Maximum allowed distance error in Blender Units",
        min=0, soft_min=0,
        default=0.0, precision=5,
        step = 0.001)

    @classmethod
    def poll(cls, context):
        return get_action(context) is not None

    def execute(self, context):
        action = get_action(context)
        options = ['DISTANCE', 'DISTANCE', 0, 5, self.error, 5, 0]

        fcurves = []
        for fc in action.fcurves:
            if fc.select:
                verts = [v.co.to_3d() for v in fc.keyframe_points.values()]
                fcurves.append(verts)

        fcurves_sel = []
        for i, fc in enumerate(action.fcurves):
            if fc.select:
                fcurves_sel.append(fc)

        for fcurve_i, fcurve in enumerate(fcurves):
            if len(fcurve) >= 3:
                new_verts = curve_simplify.simplify_RDP(fcurve, options)
                new_points = []
                for v in new_verts:
                    new_points.append(fcurve[v])
                for i in range(len(fcurve) - 1, 0, -1):
                    fcurves_sel[fcurve_i].keyframe_points.remove(fcurves_sel[fcurve_i].keyframe_points[i])
                for v in new_points:
                    fcurves_sel[fcurve_i].keyframe_points.insert(frame=v[0], value=v[1])

        return {'FINISHED'}


__REGISTER_CLASSES__ = (
    GRAPH_OT_simplify_action,
)


def register():
    for cls in __REGISTER_CLASSES__:
        bpy.utils.register_class(cls)


def unregister():
    for cls in __REGISTER_CLASSES__:
        bpy.utils.unregister_class(cls)