アクティブスプラインの制御点を概ね等間隔にする Blender Addon (とりあえず実装)

__init__.py

import bpy


bl_info = {
    'name': 'Relax Curve Control Point',
    'category': '3D View',
    'author': 'Taremin',
    'location': 'View 3D > Curve > EditMode > Context Menu',
    'description': 'カーブの制御点を整列します',
    'version': (0, 0, 2),
    'blender': (2, 80, 0),
    'wiki_url': '',
    'tracker_url': '',
    'warning': '',
}

modifier_name = '__For_CurveMapping_Workaround_By_RCCP__'

class RCCP_OT_Relax(bpy.types.Operator):
    bl_idname = "rccp.relax"
    bl_label = "Relax Curve Control Point"
    bl_options = {'REGISTER', 'UNDO'}

    cuts: bpy.props.IntProperty(name="細分化数", default=100)
    div: bpy.props.IntProperty(name="セグメント数", default=20, min=2)

    @classmethod
    def poll(cls, context):
        obj = context.active_object
        curve = obj.data.splines.active

        if curve is None:
            return True 

        return len(curve.bezier_points) >= 2

    def draw(self, context):
        layout = self.layout
        row = layout.row()
        row.prop(self, "cuts")
        row.prop(self, "div")
        
        obj = context.active_object
        layout.template_curve_mapping(obj.modifiers[modifier_name], 'falloff_curve')


    def relax_control_point(self, bp, step):
        current_length = 0
        idxs = []
        i = 0

        for idx in range(len(bp) - 1):
            p1 = bp[idx]
            p2 = bp[idx+1]
            length = (p2.co - p1.co).length

            if idx == 0:
                current_length += length
                continue

            watermark = step[i]
            if (current_length <= watermark) and (watermark < current_length + length):
                if abs(current_length - watermark) < abs(current_length + length - watermark):
                    idxs.append(idx)
                else:
                    idxs.append(idx + 1)

            if current_length > watermark and current_length + length > watermark:
                i += 1
                if i >= len(step):
                    break

            current_length += length

        return idxs

    def relax_control_point_curve(self, context, bp, total_length):
        obj = context.active_object
        modifier = obj.modifiers[modifier_name]
        curve_profile = modifier.falloff_curve

        s = 1.0 / self.div
        step = [
            curve_profile.evaluate(curve_profile.curves[0], s * (r + 1)) * total_length
                for r in range(self.div - 1)
        ]

        return self.relax_control_point(bp, step)

    def execute(self, context):
        obj = context.active_object
        curve = obj.data.splines.active
        bp = curve.bezier_points

        if obj.modifiers.find(modifier_name) < 0:
            bpy.ops.object.modifier_add(type='WARP')
            warp = obj.modifiers[-1]
            warp.name = modifier_name
            warp.show_in_editmode = False
            warp.show_viewport = False
            warp.show_render = False
            warp.show_expanded = False
            warp.falloff_type = 'CURVE'
            warp.falloff_curve.use_clip = True


        bpy.ops.curve.select_all(action='DESELECT')

        if len(curve.bezier_points) == 0:
            return {'FINISHED'}

        point = bp[0]
        point.select_control_point = True
        bpy.ops.curve.select_linked()

        bpy.ops.curve.subdivide(number_cuts=self.cuts)

        total_length = 0
        r = range(len(bp) - 1)
        for idx in r:
            p1 = bp[idx]
            p2 = bp[idx+1]
            total_length += (p2.co - p1.co).length

        idxs = [0] + self.relax_control_point_curve(context, bp, total_length) + [len(curve.bezier_points) - 1]

        bpy.ops.curve.select_all(action='DESELECT')
        point = bp[0]
        point.select_control_point = True
        bpy.ops.curve.select_linked()

        for idx in idxs:
            bp[idx].select_control_point = False
            bp[idx].select_left_handle = False
            bp[idx].select_right_handle = False
        bpy.ops.curve.dissolve_verts()

        bpy.ops.curve.select_all(action='SELECT')

        return {'FINISHED'}


def relax_control_point_button(self, context):
    self.layout.operator(
        RCCP_OT_Relax.bl_idname,
        text="Relax Curve"
    )


def register():
    bpy.utils.register_class(RCCP_OT_Relax)
    bpy.types.VIEW3D_MT_edit_curve_context_menu.append(
        relax_control_point_button)


def unregister():
    bpy.utils.unregister_class(RCCP_OT_Relax)
    bpy.types.VIEW3D_MT_edit_curve_context_menu.remove(
        relax_control_point_button)


if __name__ == "__main__":
    register()

• 2022/01/10: v0.0.2
  • 整列する際の制御点の密度をカーブで指定可能に機能追加
  • 上記変更のため、カーブには何もしないワープモディファイア __For_CurveMapping_Workaround_By_RCCP__ が追加されるようになります(Blenderの仕様上必要: https://devtalk.blender.org/t/how-do-you-add-custom-profile-prop-to-operator-like-in-bevel-operator/11521/6)