Support-Free Hollowing

Abstract

Offsetting-based hollowing is a solid modeling operation widely used in 3D printing, which can change the model's physical properties and reduce the weight by generating voids inside a model. However, a hollowing operation can lead to additional supporting structures for fabrication in interior voids, which cannot be removed. As a consequence, the result of a hollowing operation is affected by these additional supporting structures when applying the operation to optimize physical properties of different models. This paper proposes a support-free hollowing framework to overcome the difficulty of fabricating voids inside a solid. The challenge of computing a support-free hollowing is decomposed into a sequence of shape optimization steps, which are repeatedly applied to interior mesh surfaces. The optimization of physical properties in different applications can be easily integrated into our framework. Comparing to prior approaches that can generate support-free inner structures, our hollowing operation can reduce more volume of material and thus provide a larger solution space for physical optimization. Experimental tests are taken on a number of 3D models to demonstrate the effectiveness of this framework.

Ribbed Support Vaults for 3D Printing of Hollowed Objects

“…Printing the Yoda model. Left: Hollowed by support‐free hollowing [WLW*18]. Right: Printed with our method and cut open with a blade (hence the raw outline).…”

“…The method of Wang et al . [WLW*18] also considers nested self‐supported cavities. It segments the object interior space into simpler volumes, within which cavities are grown under self‐support constraints.…”

Variable-width contouring for additive manufacturing

“…Solidification inside the volume of an object is one of the main driving factors of fabrication time [Livesu et al 2017]. Thus, a line of research explores how to make insides print faster, for instance with sparse patterns [McMains et al 2000], thicker layers [Sabourin et al 1997], or by maximally emptying the part while still ensuring fabricability under overhang and support constraints Lee and Lee 2016;Tricard et al 2019;Wang et al 2017b]. Under the same constraints, other approaches seek to optimize the internal properties to achieve specific mechanical objectives, such as balance [Prévost et al 2013;Wu et al 2016], rigidity [Li et al 2015;Wang et al 2017a], density [Kuipers et al 2019] or elastic response orientation [Martínez et al 2018].…”

Structural Design Using Laplacian Shells

“…Other design approaches has been explored to generate models that do not require internal support structures to fabricate them. Topology optimization methods [Lan16; ADE*17], slice‐based hollowing methods [WLW*18] and specialized infill structures [WWZW16; LFC*18] are investigated. Although these methods are well‐suited for FDM or SLA printing processes, resulting complex structures with large number of disconnected cavities are not desirable for processes such as SLS or polyjet where excess material is typically unavoidable.…”