Poser can use strictly convex n-gons; any concave angles will render incorrectly. So, a hexagon (Allen wrench) is OK, but a star of David (Torx wrench) will render as a hexagon with the UVs badly distorted.

I'll throw in another option for architectural modeling: you can add control edges to keep Poser smoothing from making weird shadowing. It can also be used to preserve the shape in case of subdivision.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5