Matryoshka Networks: Predicting 3D Geometry via Nested Shape Layers

TL;DR

This paper introduces Matryoshka networks, a novel approach for high-resolution 3D shape reconstruction from a single image using nested shape layers, outperforming previous voxel and octree-based methods.

Contribution

It proposes a memory-efficient nested shape encoding and a simple baseline network that achieves state-of-the-art 3D reconstruction results from 2D predictions.

Findings

Outperforms voxel-based approaches in 3D shape reconstruction.

Enables detailed shapes with complex topology.

Supports shape sampling and shape ID-based reconstruction.

Abstract

In this paper, we develop novel, efficient 2D encodings for 3D geometry, which enable reconstructing full 3D shapes from a single image at high resolution. The key idea is to pose 3D shape reconstruction as a 2D prediction problem. To that end, we first develop a simple baseline network that predicts entire voxel tubes at each pixel of a reference view. By leveraging well-proven architectures for 2D pixel-prediction tasks, we attain state-of-the-art results, clearly outperforming purely voxel-based approaches. We scale this baseline to higher resolutions by proposing a memory-efficient shape encoding, which recursively decomposes a 3D shape into nested shape layers, similar to the pieces of a Matryoshka doll. This allows reconstructing highly detailed shapes with complex topology, as demonstrated in extensive experiments; we clearly outperform previous octree-based approaches despite having a much simpler architecture using standard network components. Our Matryoshka networks further enable reconstructing shapes from IDs or shape similarity, as well as shape sampling.