topic Embree 2 uses clock-wise in Intel® Embree Ray Tracing Kernels

Vertices order for normal computation

klimov__kirill — Mon, 27 Jan 2020 10:30:29 GMT

Hello!

I want to ask: which vertex order in triangle embree uses for normal computation?

As far as i can see embree uses clock-wise order. So triangle with vertices ((0, 0, 0), (1, 0, 0), (0, 1, 0)) has (0, 0, -1) normal. Also it matches with https://software.intel.com/en-us/forums/embree-photo-realistic-ray-tracing-kernels/topic/541981#comment-1814636. But i cannot find any information about it inside documentation, so i want to justify my thoughts.

Thanks in advance!

Embree 2 uses clock-wise

SvenW_Intel — Tue, 28 Jan 2020 06:15:48 GMT

Embree 2 uses clock-wise order, but in Embree 3 we changed this to counter clockwise as this is more widely used. See the figure for the description of RTC_GEOMETRY_TYPE_TRIANGLE.

Thank you!

klimov__kirill — Tue, 28 Jan 2020 07:13:11 GMT

Thank you!