- to enable mass collaboration, it is important to understand basic CAD-BOM-Build considerations that facilitate module-based design. Front left foundation level is the origin. Everything follows from there. 2x6 design with headboard with bath tub size with utility wall determines location of any component from SEH Plumbing and SEH Electrical. SEH Digital Design Rules. Design Rules apply with CAD-BOM -Build Degeneracy development phase, while Design Guidelines can be interpreted to produce various versions.
