Sculpting Holistic 3D Representation in Contrastive Language-Image-3D Pre-training

Abstract

Contrastive learning has emerged as a promising paradigm for 3D open-world understanding i.e. aligning point cloud representation to image and text embedding space individually. In this paper we introduce MixCon3D a simple yet effective method aiming to sculpt holistic 3D representation in contrastive language-image-3D pre-training. In contrast to point cloud only we develop the 3D object-level representation from complementary perspectives e.g. multi-view rendered images with the point cloud. Then MixCon3D performs language-3D contrastive learning comprehensively depicting real-world 3D objects and bolstering text alignment. Additionally we pioneer the first thorough investigation of various training recipes for the 3D contrastive learning paradigm building a solid baseline with improved performance. Extensive experiments conducted on three representative benchmarks reveal that our method significantly improves over the baseline surpassing the previous state-of-the-art performance on the challenging 1156-category Objaverse-LVIS dataset by 5.7%. The versatility of MixCon3D is showcased in applications such as text-to-3D retrieval and point cloud captioning further evidencing its efficacy in diverse scenarios. The code is available at https://github.com/UCSC-VLAA/MixCon3D.