  Text-to-3D generation has made remarkable progress recently, particularly
with methods based on Score Distillation Sampling (SDS) that leverages
pre-trained 2D diffusion models. While the usage of classifier-free guidance is
well acknowledged to be crucial for successful optimization, it is considered
an auxiliary trick rather than the most essential component. In this paper, we
re-evaluate the role of classifier-free guidance in score distillation and
discover a surprising finding: the guidance alone is enough for effective
text-to-3D generation tasks. We name this method Classifier Score Distillation
(CSD), which can be interpreted as using an implicit classification model for
generation. This new perspective reveals new insights for understanding
existing techniques. We validate the effectiveness of CSD across a variety of
text-to-3D tasks including shape generation, texture synthesis, and shape
editing, achieving results superior to those of state-of-the-art methods. Our
project page is https://xinyu-andy.github.io/Classifier-Score-Distillation
