PLANA3R: Zero-shot Metric Planar 3D Reconstruction via Feed-Forward Planar Splatting

TL;DR

PLANA3R is a novel feedforward framework that leverages planar primitives and vision transformers to achieve scalable, zero-shot metric 3D reconstruction of indoor scenes from unposed images without explicit plane supervision.

Contribution

It introduces PLANA3R, a pose-free, planar primitive-based 3D reconstruction method that learns without explicit plane annotations, enabling scalable training and strong generalization.

Findings

Effective 3D reconstruction and depth estimation on indoor datasets

Strong generalization to out-of-domain environments

Ability to perform accurate plane segmentation

Abstract

This paper addresses metric 3D reconstruction of indoor scenes by exploiting their inherent geometric regularities with compact representations. Using planar 3D primitives - a well-suited representation for man-made environments - we introduce PLANA3R, a pose-free framework for metric Planar 3D Reconstruction from unposed two-view images. Our approach employs Vision Transformers to extract a set of sparse planar primitives, estimate relative camera poses, and supervise geometry learning via planar splatting, where gradients are propagated through high-resolution rendered depth and normal maps of primitives. Unlike prior feedforward methods that require 3D plane annotations during training, PLANA3R learns planar 3D structures without explicit plane supervision, enabling scalable training on large-scale stereo datasets using only depth and normal annotations. We validate PLANA3R on multiple indoor-scene datasets with metric supervision and demonstrate strong generalization to out-of-domain indoor environments across diverse tasks under metric evaluation protocols, including 3D surface reconstruction, depth estimation, and relative pose estimation. Furthermore, by formulating with planar 3D representation, our method emerges with the ability for accurate plane segmentation. The project page is available at https://lck666666.github.io/plana3r