Hi, I am currently working on a NURBS ray tracer and I use Rhino to export STEP, IGES and other files to OBJ, which I have chosen for model import, because it is very easy to parse, unlike STEP or IGES.
The problem is that certain surfaces seem to look different when I render them with my ray tracer or even when I use NURBS package in Octave to visualize it.
This is what I see in Rhino (a sphere):
This is what I render with my ray tracer:
This is what Octave outputs:
surface.pdf (344.0 KB)
The OBJ file and Octave .m file:
rhino.zip (1.0 KB)