Add timeline animation for entity

[theamusing]

New feature: Added animation for splat entity

Timeline keyframes can now record position, rotation and scales of entities and interpolate to get animations.
Also serialized animation data into document.

2025-09-26.7.54.47.mov

Making it easier to create camera orbit animation.

Bug Fix: drag keyframes in camera poses

The original version of drag keyframe has a bug: The pose list may be changed if removed first:

const movePose = (index: number, frame: number) => {
        // remove target frame pose
        const toIndex = poses.findIndex(p => p.frame === frame);
        if (toIndex !== -1) {
            removePose(toIndex);// List may be changed!!!
        }

        // move pose
        poses[index].frame = frame;
        rebuildSpline();
        events.fire('timeline.setKey', index, frame);
    };

So the pose on index should be assigned new value before removing.

[theamusing]

#591

[slimbuck]

Hi @theamusing,

This is very interesting! I am wondering what the use-case is for animated models?

TBH I'd love to implement a full-on animation system, but I'm not really sure how many users needs that...

Is there any change you could submit the bugfix as a separate PR? 🙏🏻 I think that needs merging asap.

[theamusing]

Hi @slimbuck,
Thanks for your interest. Here are the two main reasons I want model animation:

• I used Supersplat to display 3DGS models and compare their differences from various view directions by rotating them. With model animation, this can be easily done and rendered into a single video. Otherwise, I would need to render multiple videos and then merge them.

• I want to create a camera orbiting animation (in a circle). Using the original method of interpolating camera positions with a cubic spline requires many keyframes to approximate a circle. However, with scene animation (interpolating the quaternion), it can be done much more easily.

Really appreciate your time and consideration! Supersplat is such a great project and I'm willing to contribute to it.

[theamusing]

#593 A seperate PR for bug fix. @slimbuck

[connornishijima]

I could absolutely benefit from model animation ❤️ Thanks for your hard work