This sounds like a really interesting restoration project @voiceoff. Was this part of a university/government funded project? I think you did a great job stepping through the process of creating a 3D CAD model for those who don't know how it works. I know they can throw up challenges for the model builders. I've worked in a school of Architecture before and know it's not a quick or particularly easy process. I look forward to part 2 tomorrow to see what came out of it.