Gaussian splatting represents a 3D scene as a very large number of small, soft, semi-transparent blobs — 3D Gaussians — instead of a surface made of triangles. Each one has a position, a size and orientation in three directions, an opacity and a colour that can change with the viewing angle. Drawn together, millions of them add up to something that looks like a photograph you can walk around in.
Where does it come from?
The technique was introduced in 2023 in 3D Gaussian Splatting for Real-Time Radiance Field Rendering (Kerbl et al.). It arrived as an answer to NeRFs, which could also turn photographs into explorable scenes but needed a neural network evaluated for every pixel, so they rendered slowly. A splat is explicit data — a list of Gaussians — and that list can be drawn fast on an ordinary graphics card.
How does a splat render?
Each Gaussian is projected onto the screen as a soft ellipse, the ellipses are sorted from back to front, and they are blended together. That is the "splatting": throwing soft marks at the image rather than intersecting rays with surfaces. Because it is rasterisation rather than ray marching, it runs in real time — in a browser, on a phone, in VR.
Why does a splat look so real?
Two reasons. A Gaussian's colour can depend on the direction it is seen from, so reflections and sheen shift as you move the way they do in life. And there is no surface to approximate: fine, fuzzy or semi-transparent things — foliage, hair, fabric, a dusty window — are just more blobs, where a mesh would need geometry and textures for every strand.
What is a splat bad at?
- There is no surface. No polygons, no UV layout, no clean edges. You cannot retopologise, rig or 3D print a splat directly.
- It is lit already. The lighting of the moment it was made is baked into the colours, so relighting it in an engine does not work the way it does for a mesh with materials.
- It is heavy. A large scene can be millions of Gaussians; compressed formats exist precisely because raw files run to hundreds of megabytes.
- Collisions need help. A physics engine needs a mesh to collide with, so walkable splat scenes usually ship with a simple collision mesh beside them.
Splat or mesh?
A splat is the right output when the goal is to look at a place or an object photographically — a walkthrough, a backdrop, a product turntable, a digital-twin view. A mesh is the right output when the asset has to do something — be edited, animated, collided with, printed or relit. The comparison article goes through it case by case: splats versus meshes.
Sources
- 3D Gaussian Splatting for Real-Time Radiance Field Rendering — the original paper.
- Project page — videos and the reference implementation.