Advanced fuselage options: In the options window for fuselage pieces, there will be a button that says Advanced. If you click it, it will bring up the advanced options, which are Shape: can choose between normal, triangle, pentagon, hexagon, rhombus (normal but on 45° angle), Etc. In the menu, you can change the length of individual lines, and each one will be a different color that matches a color square before the line number. If you want a triangle, the lines will be named Line 1-Line 3, and each will have a different color. Example: [(Green)] [Line 1] [Edit]. And there will be a symmetry button that makes the fuselage semetrical. Example: you have a triangle, and Side 1 is the left side, Side 2 is the right side, Side 3 is the bottom. If symmetry is active, if you change Side 1, Side 2 will mirror it, but Side 3 will stay the same.