Animation¶

The Animation class drives three.js animation tracks on the objects you previously sent to the viewer with show.

from ocp_viewer_core.viewer import show, Animation

Workflow¶

1. show(...) the assembly you want to animate.
2. Construct Animation() — this reads the paths of all objects from the last show call. It prints the available paths so you know what's addressable.
3. Add one or more tracks via add_track(path, action, times, values).
4. Call animate(speed) to play the animation in the viewer.

Animation paths are only valid for the most recent show call. Don't change the objects between show and constructing the Animation.

Adding animation tracks¶

add_track(path, action, times, values, animate_joints=False)

Adds a three.js keyframe track for one CAD object.

Raises ValueError if times and values differ in length, or if path is not in the registered paths.

Examples¶

Rotate around z by varying angles:

animation.add_track(
    '/bottom/left_middle/lower',
    'rz',
    [0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0],
    [-15.0, -15.0, -15.0, 9.7, 20.0, 9.7, -15.0, -15.0, -15.0],
)

Translate along a 3-D path:

animation.add_track(
    'base/link_4_6',
    't',
    [0.0, 1.0, 2.0, 3.0, 4.0],
    [
        [0.0, 0.0, 0.0],
        [0.0, 1.9509, 3.9049],
        [0.0, -3.2974, -16.7545],
        [0.0, 0.05894, -32.0217],
        [0.0, -3.2212, -13.3424],
    ],
)

See also: three.js NumberKeyframeTrack, three.js QuaternionKeyframeTrack.

Animate¶

animate(speed)

Plays the registered tracks in the viewer. speed is the playback multiplier (1.0 = real-time). Raises RuntimeError if no tracks have been added.

Set relative time¶

set_relative_time(fraction, port=None)

Jump the animation timeline to a fractional position between 0 (start) and 1 (end). Useful for scrubbing or for rendering specific frames.

Save as gif¶

save_as_gif(output, fps=25, loops=0, endpoint=False, bg_color="white", pause=0.02)

Renders the animation to a GIF by stepping set_relative_time and capturing screenshots.