Taming Mode Collapse in Score Distillation for Text-to-3D Generation

TL;DR

This paper identifies mode collapse as the cause of view inconsistency in text-to-3D generation and proposes Entropic Score Distillation (ESD) to enhance diversity and reduce artifacts by reintroducing an entropy term.

Contribution

It introduces ESD, a novel method that re-establishes the entropy term in score distillation, effectively mitigating Janus artifacts in text-to-3D generation.

Findings

ESD effectively reduces Janus artifacts in experiments.

Maximizing entropy encourages view diversity.

The method is simple to implement using classifier-free guidance.

Abstract

Despite the remarkable performance of score distillation in text-to-3D generation, such techniques notoriously suffer from view inconsistency issues, also known as "Janus" artifact, where the generated objects fake each view with multiple front faces. Although empirically effective methods have approached this problem via score debiasing or prompt engineering, a more rigorous perspective to explain and tackle this problem remains elusive. In this paper, we reveal that the existing score distillation-based text-to-3D generation frameworks degenerate to maximal likelihood seeking on each view independently and thus suffer from the mode collapse problem, manifesting as the Janus artifact in practice. To tame mode collapse, we improve score distillation by re-establishing the entropy term in the corresponding variational objective, which is applied to the distribution of rendered images. Maximizing the entropy encourages diversity among different views in generated 3D assets, thereby mitigating the Janus problem. Based on this new objective, we derive a new update rule for 3D score distillation, dubbed Entropic Score Distillation (ESD). We theoretically reveal that ESD can be simplified and implemented by just adopting the classifier-free guidance trick upon variational score distillation. Although embarrassingly straightforward, our extensive experiments successfully demonstrate that ESD can be an effective treatment for Janus artifacts in score distillation.