I have been working in the structural steel industry and the most common transitions we were asked to manufacture were: square to round, square to square. cones, hoppers and shoots, I know that Inventor doesn't like square to rounds but square to square can be made using surfaces. It is important for me to be able to develop and flatten half patterns so that they can be manufactured. I am missing an important step with creating surfaces, I cannot join the corners of the two surfaces, does anyone know of an example how to create transition using surfaces anywhere on the net?