Note
Go to the end to download the full example code.
Skinning Animation
This example demonstrates how to animate a skinned mesh using a glTF animation clip.
Note
To run this example, you need a model from the source repo’s example folder. If you are running this example from a local copy of the code (dev install) no further actions are needed. Otherwise, you may have to replace the path below to point to the location of the model.
import os
from pathlib import Path
try:
# modify this line if your model is located elsewhere
model_dir = Path(__file__).parents[1] / "data"
except NameError:
# compatibility with sphinx-gallery
model_dir = Path(os.getcwd()).parent / "data"
Once the path is set correctly, you can use the model as follows:
import time
import numpy as np
import pygfx as gfx
from scipy import interpolate
from wgpu.gui.auto import WgpuCanvas, run
gltf_path = model_dir / "Michelle.glb"
canvas = WgpuCanvas(size=(640, 480), max_fps=-1, title="Skinnedmesh", vsync=False)
renderer = gfx.WgpuRenderer(canvas)
camera = gfx.PerspectiveCamera(75, 640 / 480, depth_range=(0.1, 1000))
camera.local.position = (0, 100, 200)
camera.look_at((0, 100, 0))
scene = gfx.Scene()
scene.add(gfx.AmbientLight(), gfx.DirectionalLight())
gltf = gfx.load_gltf(gltf_path, quiet=True)
# gfx.print_tree(gltf.scene) # Uncomment to see the tree structure
# Group[Scene]
# - WorldObject[Character]
# - - SkinnedMesh[Ch03]
# - - Bone[mixamorig:Hips]
# - - - ...
model_obj = gltf.scene.children[0]
model_obj.local.scale = (1, 1, 1)
action_clip = gltf.animations[0]
skeleton_helper = gfx.SkeletonHelper(model_obj)
scene.add(skeleton_helper)
scene.add(model_obj)
gfx.OrbitController(camera, register_events=renderer)
def update_track(track, time):
target = track["target"]
property = track["property"]
values = track["values"]
times = track["times"]
interpolation = track["interpolation"]
if time < times[0]:
time = times[0]
# TODO: Use scipy to interpolate now, will use our own implementation later
if interpolation == "LINEAR":
if property == "rotation":
# TODO: should use spherical linear interpolation instead
cs = interpolate.interp1d(times, values, kind="linear", axis=0)
value = cs(time)
value = value / np.linalg.norm(value) # normalize quaternion
else:
cs = interpolate.interp1d(times, values, kind="linear", axis=0)
value = cs(time)
elif interpolation == "CUBICSPLINE":
cs = interpolate.interp1d(times, values, kind="cubic", axis=0)
value = cs(time)
elif interpolation == "STEP":
cs = interpolate.interp1d(times, values, kind="previous", axis=0)
value = cs(time)
else:
print("unknown interpolation", interpolation)
if property == "scale":
target.local.scale = value
elif property == "translation":
target.local.position = value
elif property == "rotation":
target.local.rotation = value
else:
print("unknown property", property)
tracks = action_clip["tracks"]
gloabl_time = 0
last_time = time.perf_counter()
stats = gfx.Stats(viewport=renderer)
def animate():
global gloabl_time, last_time
now = time.perf_counter()
dt = now - last_time
last_time = now
gloabl_time += dt
if gloabl_time > action_clip["duration"]:
gloabl_time = 0
for track in tracks:
update_track(track, gloabl_time)
model_obj.children[0].skeleton.update()
skeleton_helper.update()
with stats:
renderer.render(scene, camera, flush=False)
stats.render()
canvas.request_draw()
if __name__ == "__main__":
renderer.request_draw(animate)
run()
Total running time of the script: (0 minutes 16.721 seconds)