Without true 3D-solid modeling, laser cutting a sheetmetal-fabricated part starts with a 2D wireframe from a hardcopy blueprint. Engineering designers must calculate for bends and other part features and then, relying on experience, mentally/manually unfold the design into a flattened 2D version for laser cutting. The drawback is that only after the part is actually manufactured do they find out whether or not their calculations were correct. If they weren't, the whole process is repeated using new dimensions.
Thankfully, today's 3D-design software with sheetmetal modul