# Custom bird rig + hand-keyed clips for powder_gull (Meshy mesh, no Meshy skeleton). # blender -b -P gull_rig.py -- model.glb out.glb [out.blend] import bpy, sys, math, mathutils from mathutils import Vector, Quaternion a = sys.argv[sys.argv.index("--") + 1:] src, dst = a[0], a[1] blend = a[2] if len(a) > 2 else None bpy.ops.wm.read_factory_settings(use_empty=True) bpy.ops.import_scene.gltf(filepath=src) me = [o for o in bpy.context.scene.objects if o.type == "MESH"][0] bpy.context.view_layer.objects.active = me me.select_set(True) bpy.ops.object.transform_apply(location=True, rotation=True, scale=True) # weld UV-seam splits so weights stay continuous import bmesh bm = bmesh.new(); bm.from_mesh(me.data) bmesh.ops.remove_doubles(bm, verts=bm.verts, dist=1e-4) bm.to_mesh(me.data); bm.free() # ---- skeleton (Blender space: Z up, front -Y, character left = +X) ---- B = { "Root": ((0, 0, -0.82), (0, 0, -0.62), None), "Hips": ((0, -0.05, -0.30), (0, -0.05, 0.0), "Root"), "Chest": ((0, -0.05, 0.0), (0, -0.05, 0.22), "Hips"), "Neck": ((0, -0.05, 0.22), (0, -0.05, 0.32), "Chest"), "Head": ((0, -0.05, 0.32), (0, -0.05, 0.78), "Neck"), "Tail": ((-0.05, 0.15, -0.32), (-0.15, 0.45, -0.66), "Hips"), } for s, k in (("L", 1), ("R", -1)): lx = 0.11 if k > 0 else -0.17 B["Thigh." + s] = ((lx, -0.07, -0.30), (lx, -0.06, -0.52), "Hips") B["Shin." + s] = ((lx, -0.06, -0.52), (lx + 0.02 * k, -0.12, -0.71), "Thigh." + s) B["Foot." + s] = ((lx + 0.02 * k, -0.12, -0.71), (lx + 0.06 * k, -0.32, -0.80), "Shin." + s) wy = 0.13 if k > 0 else 0.19 B["Wing." + s] = ((0.27 * k, 0.0, 0.2), (0.6 * k, wy, 0.15), "Chest") B["Hand." + s] = ((0.6 * k, wy, 0.15), (0.95 * k, wy + 0.05, 0.2), "Wing." + s) arm_data = bpy.data.armatures.new("GullRig") arm = bpy.data.objects.new("GullRig", arm_data) bpy.context.scene.collection.objects.link(arm) bpy.context.view_layer.objects.active = arm bpy.ops.object.mode_set(mode="EDIT") for name, (h, t, p) in B.items(): eb = arm_data.edit_bones.new(name); eb.head = h; eb.tail = t for name, (h, t, p) in B.items(): if p: eb = arm_data.edit_bones[name]; eb.parent = arm_data.edit_bones[p] eb.use_connect = (Vector(arm_data.edit_bones[p].tail) - Vector(h)).length < 1e-4 bpy.ops.object.mode_set(mode="OBJECT") # ---- weights by zones ---- def smooth(t, a0, a1): """0 below a0, 1 above a1, smoothstep between.""" u = max(0.0, min(1.0, (t - a0) / (a1 - a0))) return u * u * (3 - 2 * u) groups = {n: me.vertex_groups.new(name=n) for n in B if n != "Root"} for v in me.data.vertices: x, y, z = v.co w = {} ax = abs(x); s = "L" if x > 0 else "R" if z > 0.30: w = {"Head": 1.0} elif y > 0.2 and z < -0.3: w = {"Tail": 1.0} elif ax > 0.27 and z > -0.12: # wing: chest -> wing -> hand, blended at root and elbow r = smooth(ax, 0.27, 0.36); e = smooth(ax, 0.55, 0.66) w = {"Chest": 1 - r, "Wing." + s: r * (1 - e), "Hand." + s: r * e} elif z < -0.30: legside = "L" if x > -0.04 else "R" k = smooth(z, -0.36, -0.28) # blend into hips at the top sh = 1 - smooth(z, -0.56, -0.48); ft = 1 - smooth(z, -0.74, -0.68) w = {"Hips": k, "Thigh." + legside: (1 - k) * (1 - sh), "Shin." + legside: (1 - k) * sh * (1 - ft), "Foot." + legside: (1 - k) * ft} else: c = smooth(z, -0.08, 0.08); hd = smooth(z, 0.22, 0.30) w = {"Hips": 1 - c, "Chest": c * (1 - hd), "Head": c * hd} for n, val in w.items(): if val > 1e-3: groups[n].add([v.index], val, "REPLACE") me.parent = arm mod = me.modifiers.new("Armature", "ARMATURE"); mod.object = arm # ---- animation helpers ---- def rot(axis, deg): return Quaternion(Vector(axis), math.radians(deg)) def bone_axis_rot(bone, world_axis, deg): """Rotation about a world axis expressed in the bone's rest frame.""" m = arm.data.bones[bone].matrix_local.to_3x3().inverted() return Quaternion((m @ Vector(world_axis)).normalized(), math.radians(deg)) FOLD = 55 # wings lowered along the body outside of flight def folded(pose): out = dict(pose) for sd in ("L", "R"): out["Wing." + sd] = flap(-FOLD, sd) + [(Z, 18 if sd == "L" else -18)] + list(pose.get("Wing." + sd, [])) out["Hand." + sd] = flap(-15, sd) + list(pose.get("Hand." + sd, [])) return out def make_action(name, frames, keys, loop=True, fold=True): if fold: keys = {f: folded(p) for f, p in keys.items()} """keys: {frame: {bone: (world_axis, deg) list or 'loc': Vector}}""" act = bpy.data.actions.new(name) arm.animation_data_create(); arm.animation_data.action = act bones = [b.name for b in arm.pose.bones] for f in sorted(keys): pose = keys[f] for pb in arm.pose.bones: q = Quaternion() for axis, deg in pose.get(pb.name, []): q = bone_axis_rot(pb.name, axis, deg) @ q pb.rotation_mode = "QUATERNION"; pb.rotation_quaternion = q pb.location = arm.data.bones[pb.name].matrix_local.to_3x3().inverted() @ pose.get("loc:" + pb.name, Vector()) pb.keyframe_insert("rotation_quaternion", frame=f) pb.keyframe_insert("location", frame=f) act.use_fake_user = True track = arm.animation_data.nla_tracks.new(); track.name = name track.strips.new(name, int(min(keys)), act) arm.animation_data.action = None return act X, Y, Z = (1, 0, 0), (0, 1, 0), (0, 0, 1) UP = Vector((0, 0, 1)) def flap(deg_up, s): # wing raise about the forward axis; L raises with -Y rotation return [(Y, -deg_up if s == "L" else deg_up)] clips = {} # Idle: breathing, head glance, wings settle slightly clips["Idle"] = make_action("Idle", 48, { 1: {"Chest": [(X, 0)], "Head": [(Z, 0)], "Wing.L": flap(0, "L"), "Wing.R": flap(0, "R")}, 13: {"Chest": [(X, 3)], "Head": [(Z, 12)], "Wing.L": flap(-6, "L"), "Wing.R": flap(-6, "R")}, 25: {"Chest": [(X, 0)], "Head": [(Z, 0)], "Wing.L": flap(0, "L"), "Wing.R": flap(0, "R")}, 37: {"Chest": [(X, 3)], "Head": [(Z, -12)], "Wing.L": flap(-6, "L"), "Wing.R": flap(-6, "R")}, 49: {"Chest": [(X, 0)], "Head": [(Z, 0)], "Wing.L": flap(0, "L"), "Wing.R": flap(0, "R")}, }) def walk_pose(ph): sw = math.sin(ph); lift = max(0, math.sin(ph)); liftR = max(0, -math.sin(ph)) return {"Thigh.L": [(X, -28 * sw)], "Thigh.R": [(X, 28 * sw)], "Shin.L": [(X, 25 * lift)], "Shin.R": [(X, 25 * liftR)], "Hips": [(Y, 7 * sw)], "Chest": [(Y, -4 * sw)], "Head": [(X, -6 * abs(math.cos(ph)))], "Wing.L": flap(-8 + 5 * sw, "L"), "Wing.R": flap(-8 - 5 * sw, "R"), "loc:Root": Vector((0, 0, 0.045 + 0.025 * abs(math.cos(ph))))} clips["Walk"] = make_action("Walk", 24, {1 + i * 3: walk_pose(i * math.pi / 4) for i in range(9)}) def fly_pose(ph): up = math.sin(ph); lag = math.sin(ph - 0.9) return {"Wing.L": flap(42 * up, "L"), "Wing.R": flap(42 * up, "R"), "Hand.L": flap(28 * lag, "L"), "Hand.R": flap(28 * lag, "R"), "Hips": [(X, -18)], "Thigh.L": [(X, 70)], "Thigh.R": [(X, 70)], "Shin.L": [(X, -40)], "Shin.R": [(X, -40)], "Tail": [(X, -10)], "Head": [(X, 14)], "loc:Root": Vector((0, 0, 0.35 - 0.05 * up))} clips["Fly"] = make_action("Fly", 16, {1 + i * 2: fly_pose(i * math.pi / 4) for i in range(9)}, fold=False) # Attack (dive bomb): wings up, crouch, lunge + peck, recover clips["Attack"] = make_action("Attack", 22, { 1: {}, 6: {"Wing.L": flap(55, "L"), "Wing.R": flap(55, "R"), "Hips": [(X, 10)], "Head": [(X, -15)], "Thigh.L": [(X, -15)], "Thigh.R": [(X, -15)], "loc:Root": Vector((0, 0.05, 0.0))}, 11: {"Wing.L": flap(-35, "L"), "Wing.R": flap(-35, "R"), "Hips": [(X, -35)], "Head": [(X, 35)], "Thigh.L": [(X, 35)], "Thigh.R": [(X, 35)], "loc:Root": Vector((0, -0.28, 0.14))}, 15: {"Wing.L": flap(-20, "L"), "Wing.R": flap(-20, "R"), "Hips": [(X, -25)], "Head": [(X, 20)], "loc:Root": Vector((0, -0.22, 0.06))}, 23: {}, }, loop=False) # Hurt: recoil backwards, wings jolt clips["Hurt"] = make_action("Hurt", 12, { 1: {}, 4: {"Hips": [(X, 18)], "Head": [(X, -25), (Z, 15)], "Wing.L": flap(35, "L"), "Wing.R": flap(25, "R"), "loc:Root": Vector((0, 0.08, 0.07))}, 13: {}, }, loop=False) # Death: topple onto its back, wings drop open clips["Death"] = make_action("Death", 30, { 1: {}, 8: {"Hips": [(X, 25)], "Head": [(X, -30)], "Wing.L": flap(40, "L"), "Wing.R": flap(40, "R"), "loc:Root": Vector((0, 0.05, 0.08))}, 20: {"Root": [(X, 80)], "Head": [(X, -20), (Z, 25)], "Wing.L": flap(-30, "L"), "Wing.R": flap(-30, "R"), "Thigh.L": [(X, 50)], "Thigh.R": [(X, 30)], "loc:Root": Vector((0, 0.1, 0.3))}, 30: {"Root": [(X, 88)], "Head": [(X, -15), (Z, 30)], "Wing.L": flap(-35, "L"), "Wing.R": flap(-35, "R"), "Thigh.L": [(X, 55)], "Thigh.R": [(X, 35)], "Shin.L": [(X, -30)], "loc:Root": Vector((0, 0.12, 0.45))}, }, loop=False) for act in bpy.data.actions: for fc in act.fcurves if hasattr(act, "fcurves") else []: for kp in fc.keyframe_points: kp.interpolation = "BEZIER" # ---- ground check: lowest evaluated vertex per clip at a few frames ---- dg = bpy.context.evaluated_depsgraph_get() for name, act in clips.items(): arm.animation_data.action = act lows = [] for f in (1, 6, 12, 20): bpy.context.scene.frame_set(f) dg = bpy.context.evaluated_depsgraph_get() e = me.evaluated_get(dg); m = e.to_mesh() lows.append(round(min((e.matrix_world @ vv.co).z for vv in m.vertices), 3)); e.to_mesh_clear() print("GROUND", name, lows) arm.animation_data.action = None if blend: bpy.ops.wm.save_as_mainfile(filepath=blend) bpy.ops.object.select_all(action="DESELECT") me.select_set(True); arm.select_set(True) bpy.ops.export_scene.gltf(filepath=dst, export_format="GLB", use_selection=True, export_animations=True, export_animation_mode="ACTIONS") print("EXPORTED", dst, list(clips))