NeRF-VAE: A Geometry Aware 3D Scene Generative Model
Adam R. Kosiorek, Heiko Strathmann, Daniel Zoran, Pol Moreno, Rosalia Schneider, Soňa Mokrá, Danilo J. Rezende
TL;DR
NeRF-VAE addresses 3D scene generation by embedding a geometry-aware NeRF-based decoder within a variational framework. It introduces a view-invariant latent z and a conditional scene function to capture shared scene priors, enabling rapid amortized inference for novel scenes and view-consistent rendering via differentiable volume rendering. The approach demonstrates improved generalization to out-of-distribution cameras and the ability to model uncertainty from limited context, with an attention-based conditioning mechanism enhancing performance. The work highlights the benefits and limitations of combining explicit geometry with learned priors and points toward future work on dynamic scenes and richer latent representations.
Abstract
We propose NeRF-VAE, a 3D scene generative model that incorporates geometric structure via NeRF and differentiable volume rendering. In contrast to NeRF, our model takes into account shared structure across scenes, and is able to infer the structure of a novel scene -- without the need to re-train -- using amortized inference. NeRF-VAE's explicit 3D rendering process further contrasts previous generative models with convolution-based rendering which lacks geometric structure. Our model is a VAE that learns a distribution over radiance fields by conditioning them on a latent scene representation. We show that, once trained, NeRF-VAE is able to infer and render geometrically-consistent scenes from previously unseen 3D environments using very few input images. We further demonstrate that NeRF-VAE generalizes well to out-of-distribution cameras, while convolutional models do not. Finally, we introduce and study an attention-based conditioning mechanism of NeRF-VAE's decoder, which improves model performance.
