bl_info = { "name": "Action Start Cleaner", "version": (1, 0, 0), "blender": (4, 0, 0), "location": "View3D > Sidebar > Animation > Action Start Cleaner", "description": "Shift Actions so their first keyframe starts at the chosen frame.", "category": "Animation", } import bpy from bpy.props import BoolProperty, EnumProperty, FloatProperty, PointerProperty def iter_action_fcurves(action): if not action: return seen = set() if hasattr(action, "fcurves"): for fcurve in action.fcurves: pointer = fcurve.as_pointer() seen.add(pointer) yield fcurve for layer in getattr(action, "layers", []): for strip in getattr(layer, "strips", []): for channelbag in getattr(strip, "channelbags", []): for fcurve in getattr(channelbag, "fcurves", []): pointer = fcurve.as_pointer() if pointer not in seen: seen.add(pointer) yield fcurve def active_action_for_armature(armature): if not armature or armature.type != "ARMATURE": return None if not armature.animation_data: return None return armature.animation_data.action def action_first_keyframe(action): first = None for fcurve in iter_action_fcurves(action): for point in fcurve.keyframe_points: frame = float(point.co.x) if first is None or frame < first: first = frame return first def shift_fcurve_frames(fcurve, delta): for point in fcurve.keyframe_points: point.co.x += delta point.handle_left.x += delta point.handle_right.x += delta fcurve.update() def shift_action_to_start(action, target_start): first = action_first_keyframe(action) if first is None: return None, 0.0 delta = float(target_start) - first if abs(delta) < 0.000001: return first, 0.0 for fcurve in iter_action_fcurves(action): shift_fcurve_frames(fcurve, delta) return first, delta class ACTIONSTARTCLEANER_Settings(bpy.types.PropertyGroup): armature: PointerProperty( name="Armature", description="Armature whose active Action should be shifted when Scope is Active Action", type=bpy.types.Object, poll=lambda self, obj: obj.type == "ARMATURE", ) scope: EnumProperty( name="Scope", description="Choose whether to shift the active Action or all Actions", items=( ("ACTIVE", "Active Action", "Shift only the Action currently assigned to the chosen armature"), ("ALL", "All Actions", "Shift every Action in the file"), ), default="ALL", ) start_mode: EnumProperty( name="Start", description="Target start frame", items=( ("FRAME_1", "Frame 1", "Move first keyframe to frame 1"), ("SCENE_START", "Scene Start", "Move first keyframe to the scene start frame"), ("CUSTOM", "Custom", "Move first keyframe to a custom frame"), ), default="FRAME_1", ) custom_start_frame: FloatProperty( name="Custom Frame", description="Custom target frame used when Start is Custom", default=1.0, ) dry_run: BoolProperty( name="Dry Run", description="Only report what would be shifted", default=True, ) print_details: BoolProperty( name="Print Details", description="Print old first keyframe and shift amount to the console", default=True, ) class ACTIONSTARTCLEANER_OT_clean(bpy.types.Operator): bl_idname = "object.action_start_cleaner_clean" bl_label = "Move First Keyframe To Start" bl_description = "Shift selected Actions so their first keyframe starts at the chosen frame" bl_options = {"REGISTER", "UNDO"} def execute(self, context): settings = context.scene.action_start_cleaner armature = settings.armature or context.object if settings.start_mode == "SCENE_START": target_start = float(context.scene.frame_start) elif settings.start_mode == "CUSTOM": target_start = settings.custom_start_frame else: target_start = 1.0 if settings.scope == "ACTIVE": if not armature or armature.type != "ARMATURE": self.report({"ERROR"}, "Choose an armature or select one") return {"CANCELLED"} action = active_action_for_armature(armature) if not action: self.report({"ERROR"}, "Chosen armature has no active Action") return {"CANCELLED"} actions = [action] else: actions = list(bpy.data.actions) shifted = 0 unchanged = 0 empty = 0 for action in actions: first = action_first_keyframe(action) if first is None: empty += 1 if settings.print_details: print(f"Action Start Cleaner: empty Action {action.name!r}") continue delta = target_start - first if abs(delta) < 0.000001: unchanged += 1 if settings.print_details: print(f"Action Start Cleaner: unchanged {action.name!r}, first={first:g}") continue shifted += 1 if settings.print_details: verb = "Would shift" if settings.dry_run else "Shifting" print( f"Action Start Cleaner: {verb} {action.name!r}, " f"first={first:g}, target={target_start:g}, delta={delta:g}" ) if not settings.dry_run: shift_action_to_start(action, target_start) verb = "Would shift" if settings.dry_run else "Shifted" self.report({"INFO"}, f"{verb} {shifted} Action(s). Unchanged {unchanged}. Empty {empty}.") return {"FINISHED"} class ACTIONSTARTCLEANER_PT_panel(bpy.types.Panel): bl_label = "Action Start Cleaner" bl_idname = "ACTIONSTARTCLEANER_PT_panel" bl_space_type = "VIEW_3D" bl_region_type = "UI" bl_category = "Animation" def draw(self, context): layout = self.layout settings = context.scene.action_start_cleaner layout.prop(settings, "scope") if settings.scope == "ACTIVE": layout.prop(settings, "armature") layout.prop(settings, "start_mode") if settings.start_mode == "CUSTOM": layout.prop(settings, "custom_start_frame") layout.prop(settings, "dry_run") layout.prop(settings, "print_details") layout.operator(ACTIONSTARTCLEANER_OT_clean.bl_idname) classes = ( ACTIONSTARTCLEANER_Settings, ACTIONSTARTCLEANER_OT_clean, ACTIONSTARTCLEANER_PT_panel, ) def register(): for cls in classes: bpy.utils.register_class(cls) bpy.types.Scene.action_start_cleaner = PointerProperty(type=ACTIONSTARTCLEANER_Settings) def unregister(): if hasattr(bpy.types.Scene, "action_start_cleaner"): del bpy.types.Scene.action_start_cleaner for cls in reversed(classes): try: bpy.utils.unregister_class(cls) except RuntimeError: pass if __name__ == "__main__": register()