DensiCrafter: Physically-Constrained Generation and Fabrication of Self-Supporting Hollow Structures

TL;DR

DensiCrafter is a novel framework that generates lightweight, self-supporting hollow 3D structures by optimizing density fields with physical constraints, enabling manufacturable designs from pretrained models.

Contribution

It introduces a physically-constrained, differentiable optimization method for generating self-supporting hollow structures integrated with existing 3D generative models.

Findings

Achieves up to 43% reduction in material mass.

Improves stability and geometric fidelity over baselines.

Designs are reliably fabricated and self-supporting in real-world printing.

Abstract

The rise of 3D generative models has enabled automatic 3D geometry and texture synthesis from multimodal inputs (e.g., text or images). However, these methods often ignore physical constraints and manufacturability considerations. In this work, we address the challenge of producing 3D designs that are both lightweight and self-supporting. We present DensiCrafter, a framework for generating lightweight, self-supporting 3D hollow structures by optimizing the density field. Starting from coarse voxel grids produced by Trellis, we interpret these as continuous density fields to optimize and introduce three differentiable, physically constrained, and simulation-free loss terms. Additionally, a mass regularization penalizes unnecessary material, while a restricted optimization domain preserves the outer surface. Our method seamlessly integrates with pretrained Trellis-based models (e.g., Trellis, DSO) without any architectural changes. In extensive evaluations, we achieve up to 43% reduction in material mass on the text-to-3D task. Compared to state-of-the-art baselines, our method could improve the stability and maintain high geometric fidelity. Real-world 3D-printing experiments confirm that our hollow designs can be reliably fabricated and could be self-supporting.