StructureNet: Hierarchical Graph Networks for 3D Shape Generation

TL;DR

StructureNet is a hierarchical graph network that encodes and generates diverse, realistic 3D shapes with complex part structures, advancing shape generation, editing, and discovery through a novel n-ary graph encoding approach.

Contribution

It introduces a novel order-invariant hierarchical graph neural network capable of encoding and generating complex 3D shapes with structured part hierarchies.

Findings

Significant improvements over baseline methods in shape quality.

Effective shape interpolation and editing demonstrated.

Robust shape structure discovery from various data sources.

Abstract

The ability to generate novel, diverse, and realistic 3D shapes along with associated part semantics and structure is central to many applications requiring high-quality 3D assets or large volumes of realistic training data. A key challenge towards this goal is how to accommodate diverse shape variations, including both continuous deformations of parts as well as structural or discrete alterations which add to, remove from, or modify the shape constituents and compositional structure. Such object structure can typically be organized into a hierarchy of constituent object parts and relationships, represented as a hierarchy of n-ary graphs. We introduce StructureNet, a hierarchical graph network which (i) can directly encode shapes represented as such n-ary graphs; (ii) can be robustly trained on large and complex shape families; and (iii) can be used to generate a great diversity of realistic structured shape geometries. Technically, we accomplish this by drawing inspiration from recent advances in graph neural networks to propose an order-invariant encoding of n-ary graphs, considering jointly both part geometry and inter-part relations during network training. We extensively evaluate the quality of the learned latent spaces for various shape families and show significant advantages over baseline and competing methods. The learned latent spaces enable several structure-aware geometry processing applications, including shape generation and interpolation, shape editing, or shape structure discovery directly from un-annotated images, point clouds, or partial scans.