[jtolmar]

Gaussian splatting models the scene as a bunch of normal distributions (fuzzy squished spheres) instead of triangles, then renders those with billboarded triangles. It has advantages (simpler representation, easy to automatically capture from a scan) and disadvantages (not what the hardware is designed for, not watertight). The biggest disadvantage is that most graphics techniques need to be reinvented for it, and it's not clear what the full list of advantages and disadvantages will be until people have done all of those. But that big disadvantage is also a great reason to make tons of papers.

[marcellus23]

what does "not watertight" mean?

[lambdaone]

They don't create contiguous surfaces, and GPUs are optimized to deal with sets of triangles that share vertices (a vertex typically being shared by four to six triangles), rather than not shared at all as with this.

"Watertight" is a actially a stronger criterion, which requires not only a contigous surface, but one which encloses a volume without any gaps, but "not watertight" suffices for this.