An overhang constraint adaptable to a proper building orientation

In additive manufacturing processes, the critical overhang angle of downward facing surfaces limits printability of parts. To consider this limitation of the process in topology optimization, several approaches have been proposed in the literature. Most of them operate with a user-defined building direction, thus, if the orientation is not appropriate, structural performance could be drastically compromised. This work aims to reduce the dependence of the user on the definition of the building direction. We make use of a gradient-based constraint due to the low computation cost it demands in comparison to layer-by-layer approaches. The method is demonstrated on 2D and 3D examples.