Smooth Polygons.
You enabled "Smooth Polygons" in the render settings.

This works in combination witht the crease angle that you can set in each group in the groups properties.

Disable Smooth Polygons in the renders ettings.

Or uncheck the option "Smooth polygons" in the groups that you do not want smoothed.

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
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