https://community.intel.com/t5/Intel-Embree-Ray-Tracing-Kernels/Backface-culling-determination/m-p/1015079#M365 <P>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.&nbsp;<SPAN style="font-size: 1em; line-height: 1.5;">In case of your cylinder only the front facing triangles would get hit by the ray.</SPAN></P> Tue, 26 May 2015 05:10:40 GMT SvenW_Intel 2015-05-26T05:10:40Z https://community.intel.com/t5/Intel-Embree-Ray-Tracing-Kernels/Backface-culling-determination/m-p/1015078#M364 <P>Wondering how Embree determines which faces are 'backfacing' when this option is enabled upon compilation or set for a geometry.&nbsp;</P> <P>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?</P> <P>A simple example being a ray passing through the barrel of a cylinder with some triangle normals facing the ray and others not.</P> <P>&nbsp;</P> <P>&nbsp;</P> Mon, 25 May 2015 18:08:49 GMT https://community.intel.com/t5/Intel-Embree-Ray-Tracing-Kernels/Backface-culling-determination/m-p/1015078#M364 Patrick_S_4 2015-05-25T18:08:49Z https://community.intel.com/t5/Intel-Embree-Ray-Tracing-Kernels/Backface-culling-determination/m-p/1015079#M365 <P>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.&nbsp;<SPAN style="font-size: 1em; line-height: 1.5;">In case of your cylinder only the front facing triangles would get hit by the ray.</SPAN></P> Tue, 26 May 2015 05:10:40 GMT https://community.intel.com/t5/Intel-Embree-Ray-Tracing-Kernels/Backface-culling-determination/m-p/1015079#M365 SvenW_Intel 2015-05-26T05:10:40Z