You're probably thinking of 3D Gaussian Splatting (3DGS), another fantastic approach to real-time novel view synthesis. There's tons of fantastic work being built on 3DGS right now, and the dust has yet to settle with respect to which method is "better". Right now, I can say that SMERF has slightly higher quality on than 3DGS on small scenes and visibly higher quality on big scenes and runs on a wider variety of devices, but takes much longer than 3DGS to train.
but perhaps that was biased?