4D and 2D Gaussian Splatting Explained
Guide · 2026-06-08 · 6 min read · by SplatMart Team
Beyond standard 3D splats there's 4D (splats that move over time) and 2D (flat disc primitives for sharper surfaces). Here's what each means and when it matters.
Standard Gaussian splatting captures a static 3D scene. But you'll also see the terms 4D Gaussian splatting and 2D Gaussian splatting. They are not typos: 4D adds time (splats that move and change), and 2D swaps the 3D blobs for flat discs to get cleaner surfaces. Here's what each one actually means and when you'd want it.
What is 4D Gaussian splatting?
4D Gaussian splatting extends a splat with a fourth dimension — time — so the scene can move. Instead of a frozen moment, you capture a dynamic scene (a person waving, water flowing, a flag in the wind) and the Gaussians shift, deform, and change colour over time. The "4D" is the usual 3D space plus time.
What it's used for
- Volumetric video — recording a real performance you can replay from any angle.
- Dynamic scenes for VR/AR and virtual production.
- Research into real-time dynamic scene rendering.
The trade-off is cost: 4D captures are heavier to record, far larger to store, and harder to process than static splats, because every moment in time needs its own description. The field is moving fast, but static 3D splats remain the practical default for most projects.
What is 2D Gaussian splatting?
2D Gaussian splatting replaces the 3D ellipsoid blobs with flat, oriented 2D discs (sometimes called surfels). Because real-world surfaces are essentially thin, aligning flat discs to them produces more accurate geometry and cleaner surface reconstruction — which is especially useful if your goal is to extract a mesh from the splat.
Why use 2D instead of 3D splats
- Sharper, more accurate surfaces — less "fuzz" on walls, floors, and objects.
- Better mesh extraction — the discs hug the true surface, so converting to a traditional 3D mesh is cleaner.
- Good for scanning and reconstruction workflows where geometry accuracy matters more than raw speed.
Which one do you need?
- Most people want standard 3D Gaussian splatting — the best balance of realism and real-time speed. See our guide to what Gaussian splatting is.
- Choose 4D if your subject moves and you need to capture motion over time.
- Choose 2D if you care most about accurate surfaces or want to turn the capture into a clean mesh.
Whatever variant you explore, you can start from ready-made 3D splats. Browse SplatMart to see high-quality static splats across categories.
Frequently asked questions
What is 4D Gaussian splatting?
It is Gaussian splatting with time added, so the scene can move and change. It is used for volumetric video and dynamic scenes, at the cost of much larger data and heavier processing than static 3D splats.
What is 2D Gaussian splatting?
It uses flat oriented discs instead of 3D blobs. Because surfaces are thin, the discs align to them better, giving more accurate geometry and cleaner mesh extraction.
Is 4D splatting just a video?
No. A video is fixed to one camera path. A 4D splat is a moving 3D scene you can replay from any angle and position, like volumetric video.
Should beginners use 2D or 4D splatting?
Neither to start. Begin with standard 3D Gaussian splatting; reach for 2D when you need accurate surfaces or meshes, and 4D when you need to capture motion.