Inconsistent orientation of render meshes

Hello everybody,

I apologize in advance if the question is stupid, but I could not find the answer either on the forums or in the documentation.
I am using the latest openNURBS library to load 3DM files. I just extract render meshes for visualization purposes. The problem is that for BRep geometries, the meshes are not oriented consistently, as shown in the attached image (black areas correspond to meshes with flipped normals). I tried to use the m_bRev flag of BRep’s face to flip reversed meshes manually, but it does not lead to the correct result. Could you please clarify, how the orientation of individual render meshes can be handled correctly? Thanks in advance.

I’d venture a guess here that your original.surfaces already are flipped. You can check that easiest by creating a copy of say the Shaded mode (Tools » Options » View » Display Modes), rename the copy to say ShadedBF. Then change Backface under the display mode settings shading section to a single color. I use a red or pink shade.

Now change your viewport to your newly created ShadedBF. Do the black parts match the backface shading?