Hi , it there anyone knowing how to use Birails tools proper (1,2+3). Every time I model I do get "black spot" in some corners. Even when I add more span or rebuild curve/surface (same amount) I do get the black spots . Sorry for my english. So my question is how to model proper (In My case head) with Birails tools and how to get the "tansion" off the corners. Please need help here. It is hard to model with Biralis since it is so nervous, even to turn direction (surface) one way or another make the normals normals does not help. thx