Hi again,

didn't thougt my initial question would cause such an informative discussion.

Tested some more.

Poser has "Smoothing Groups" functionality (those groups can be created in the group editor). Documentation says polys that belong to different Smoothing Groups will be shaded indepentend from each other. Means, the smoothing by the phong shading does not cross the borders between those groups. That means one can keep merged edges, have a higher crease angle and still get sharp edges.

I tried it out and come to the conclusion that it works, but it is tricky as the ceometry within each group is relevant too.

I made two versions of the "room" now. One with "triangle like quads" and with "quad like quads". Everthing else (mats, smoothing groups, crease angle) is the same for both.