Hi there,
I think my “problem” is quite particular. Currently I’m also doing concept sketches and I’d like to visualize some imaginary buildings. Also probably from extreme viewpoints not easily to do with real objects.
Also I don’t really fancy to use my rulers and build the whole perspective on my desk by hand.
I discovered a technique that is used in anime production: Rendering a model in the computer and then use it for tracing, adding other elements directly by hand for the beautiful backgrounds.
Also I like the idea of building my world with virtual brick and mortar and then going on a virtual sketchcrawl. Well, I’ve done 3d graphics over a decade ago and am completely out of business.
So, does anybody anything similar, I’m open for suggestions.

This is something I did around 2006. I used it as a quick illustration to see whether the concept works and how the shadows would look. Later I built a part of the cityscape in a different program and had it rendered in 3d.