primorge posted at 3:39 PM Sat, 18 December 2021 - #4432074

Most programs calculate normals on load. I don't think I've ever encountered an instance where deleting the vn lines from OBJ had any effect upon importing to various environments. It's my understanding there are certain instances where Poser recalculates normals on the fly during certain processes, or so I've heard. Can't remember the particulars but I think it involved solving some scene bug, and it was a workaround, perhaps discussed by Bagginsbill.

All I know is that when RDNA adapted Antonia, they removed the normal data from the OBJ because supposedly Poser does not use it and always recomputes the normals on load. I've never checked that myself, but I guess it can't hurt to leave the normals out and save about 30% of disk space for storing the file.

But Blender definitely uses what's in the file unless one recomputes the normals explicitly. That can be useful when one does elaborate mesh surgery and wants the normals to stay consistent, so it makes sense for a program like Blender to use them. For Poser, it's probably much less useful.

If you're really keen on seeing the effect, I can send you a demo file. :smile:

-- I'm not mad at you, just Westphalian.