A Simple Method for Correcting Facet Orientations in Polygon Meshes Based on Ray Casting

We present a method for fixing incorrect orientations of facets in an input polygon mesh, a problem often seen in popular 3D model repositories, such that the front side of facets is visible from viewpoints outside of a solid shape represented or implied by the mesh. As opposed to previously proposed methods which are rather complex and hard to reproduce, our method is very simple, only requiring sampling visibilities by shooting many rays. We also propose a simple heuristic to handle interior facets that are invisible from exterior viewpoints. Our method is evaluated extensively with the SHREC'10 Generic 3D Warehouse dataset containing manually designed meshes, and is demonstrated to be very effective.

Kenshi Takayama, Alec Jacobson, Ladislav Kavan, Olga Sorkine-Hornung. A Simple Method for Correcting Facet Orientations in Polygon Meshes Based on Ray Casting. Journal of Computer Graphics Techniques 3(4), 2014.  

We are grateful to Peter Kaufmann, Wenzel Jakob, Nobuyuki Umetani, Melina Skouras, Ilya Baran, and Ryan Schmidt for their advice and feedback. This work was supported in part by the ERC grant iModel (StG-2012-306877), by an SNF award 200021_137879, by a NSF grant IIS-1350330, and by a gift from Adobe Research. Kenshi Takayama’s work was funded in part by JSPS Postdoctoral Fellowships for Research Abroad. Alec Jacobson’s work was supported in part by an Intel Doctoral Fellowship.