LL3DA: Visual Interactive Instruction Tuning for Omni-3D Understanding, Reasoning, and Planning.

Recent advances in Large Multimodal Models (LMM) have made it possible for various applications in human-machine interactions. However, developing LMMs that can comprehend, reason, and plan in complex and diverse 3D environments remains a challenging topic, especially considering the demand for understanding permutation-invariant point cloud 3D representations of the 3D scene. Existing works seek help from multi-view images, and project 2D features to 3D space as 3D scene representations. This, however, leads to huge computational overhead and performance degradation. In this paper, we present LL3DA, a Large Language 3D Assistant that takes point cloud as direct input and respond to both textual-instructions and visual-prompts. This help LMMs better comprehend human interactions and further help to remove the ambiguities in cluttered 3D scenes. Experiments show that LL3DA achieves remarkable results, and surpasses various 3D vision-language models on both 3D Dense Captioning and 3D Question Answering.

Overview of the Proposed Approach. (a) The overall pipeline of our proposed LL3DA first extracts interaction-aware 3D scene embeddings, which are later projected to the prefix of textual instructions as the input of a frozen LLM. (b) The detailed design of the Interactor3D, which aggregates visual prompts, textual instructions, and 3D scene embeddings into a fixed length querying tokens. (c) The prompt encoder encodes the user clicks and box coordinates with the positional embeddings and ROI features, respectively.