- 1 · Source
- 2 · Rebuilt
- 3 · New angle
- 4 · Ghost trail
- 5 · Spacetime
- 6 · Capture report
Clips of 4D reconstruction are everywhere right now: a video turned into 3D frame by frame, each frame left where and when it happened, so moving things leave trails through space. We built our own pipeline from open parts and ran it on a screen recording of our factory showcase. The still hall became a Gaussian splat; every robot and worker that moves was rebuilt in 3D for each of 155 frames. In the browser you can scrub time, run it backwards, freeze a moment and walk round it, or leave ghost trails. A capture report runs underneath: how much of each frame moves, how fast the camera turns, a plan view of where it went, events to jump to, and a build-up of every moving point in the order it was captured.
What we measured
| Measure | Still world only | Plus rebuilt moving points | Note |
|---|---|---|---|
| Match to the video in moving regions | 14.8 dB | 17.3 dB | PSNR from the original camera, mean of 5 frames |
| Match over the whole picture | 23.7 dB | 23.9 dB | |
| Camera solved | n/a | 165 of 165 frames | 0.7 px reprojection error |
| Depth error on held-out points | n/a | 2.4% | Median; 3.3% at the 90th percentile |
| Busiest moment | n/a | 1.6 s | 1.6% of the frame moving there; 0.8% on average |
| Fastest camera turn | n/a | 81°/s | At 1.7 s; the camera turns 38° over the clip and never holds still |
| Download | n/a | 13 MB | Splat 9.0 MB, moving points 3.5 MB, video 0.3 MB |
| Processing, 5.5 s clip | n/a | about 11 min | Camera solve 5.5 min (CPU), depth 43 s, motion 49 s, splat 2 min 50 s |
What happens next
- Our own phone footage of people moving, closer than a drone.
- Tracking each moving thing as one object across frames, so it can be seen from more sides and trails stop shimmering.
- Several videos placed into one scene, so different moments and seasons share a place.
- Stereo and WebXR, to stand inside the moment in a headset.
Get the book today: learn Gaussian splatting and apply it to real projects.
People keep asking how we build what you see here. The book walks students, educators and practitioners from a drone clip to a measured 3D in the browser, with hands-on labs and the code.
Launch price until 3 December.
Teaching a course (Level 5, Level 6 and up)? Email junaid.malik@simamdigital.com about a class discount.