Help:Workflow
From WireCAD Online Help
There are a number of different ways to approach system design. Probably as many as those engaged in the effort. None of these are wrong if they produce the desired output. That said, we must have an idea of what the desired output is and where we want to start.
For some engineers it starts with the functional block diagrams. Truth be told, that is the approach of the author. Others choose to design rack layouts first then create the functional block diagrams to support. In either case WireCAD can accommodate.