There are THREE main categories of developments that a Boilermaker needs to know, they are Parallel line, Radial line and Triangulation line developments. We begin our course with video tutorials using Parallel line development to obtain the true shape of a joints seam. This method is often used for rounded shapes such as steel cylinders and lobster back bends with or without branch segments extending off from the main cylinder in another direction such as an offset unequal diameter T piece.