OCC mesh

Hello,

I am using both OCC and Netgen mesh for exporting meshed elements coordinates to GDML file regarding to tessellated shapes. The Tessellated shape in GDML is defined by facets and facets are defined by verities. According to GDML, vertices should be “Anti-clockwise/Counter-clockwise” order when looking outside the shape.

I observed that the triangle in Netgen mesh is followed the "counter-clockwise" direction. But the OCC mesh is followed the "clockwise" direction. Note that, I have checked very carefully in our exporting implementation. I assume that perhaps OCC mesh (“BRepMesh”) works as clockwise.

My questions are:
1. How to change the order in triangle (clockwise to counter-clockwise) after/before OCC mesh?
2. How to make point upward or downward in OCC?
3. How to check point direction in OCC for each surface/triangle?

I attached partial outputs both for OCC and Netgen mesh.

Thanks in advance.