Intel® Embree Ray Tracing Kernels
Discussion forum on the open source ray tracing kernels for fast photo-realistic rendering on Intel® CPUs.

Backface culling determination

Patrick_S_4
Beginner
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Wondering how Embree determines which faces are 'backfacing' when this option is enabled upon compilation or set for a geometry. 

Do all triangles in the surface need to be backfacing for the surface to be ignored by the ray? Or only the ones which would typically be hit by the ray?

A simple example being a ray passing through the barrel of a cylinder with some triangle normals facing the ray and others not.

 

 

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SvenW_Intel
Moderator
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Triangles whose geometry normal are pointing towards the ray are font faceing, the others backfacing. Backfacing triangle hits are ignored per ray if the RTC_BACKFACE_CULLING feature is enabled. In case of your cylinder only the front facing triangles would get hit by the ray.

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