Quote - I see now, it's a shadows rendering difference and not a geometry difference. Don't know why it happens, it looks as if the shadows were averaged from the values at some points or vertices, smaller the polygons lesser the error in the average.

It's a problem of Lux and some other renderers that we've been talking about earlier (look for the posts by bagginsbill and rty on page 37, for example). Shading normals can be interpolated, but when the discrepancy between the interpolated normals and the actual polygon normals get too large, the renderer can get confused. That is quite obvious when you have a terminator (boundary between the lit and unlit side of an object), because there it's not just a question of how to shade a certain pixel, but first of all whether it receives any light from a particular light source at all.

PS: If you look closely at the outlines of the shoulders, you'll see that they are a bit smoother, too, in the subdivided version. But that alone would have hardly been worth the effort.

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