The coincidence site lattice (CSL) plays a similar role for grain boundaries ( GB) as the crystal lattice plays for free surfaces. The most densely packed CSL is the twin-related CSL, characterized by an inverse density of coincidence sites Sigma = 3. Phase diagrams in coordinates "relative temperature T/T(m)-misorientation angle theta-inclination angle phi" were constructed for the twin GBs in Cu, Al, and Mo having different stacking fault energy gamma. At low gamma the twin GB remains faceted at all phi values and the number of crystallographically different facets increases with decreasing temperature. With increasing gamma asymmetric twin GBs become more and more rough, and fewer facets appear with decreasing temperature. Also, with increasing gamma the facets start to degenerate of into the first order rough-to-rough ridges. The behavior of twin GBs in Cu, Al, and Mo is compared with that of twin GBs in Zn.