Do we have a way to export map tile geometry?

[Holy_Diver]

I was just wondering how you guys are able to make new map tiles that mesh with the originals, if you are able...

I know for instance Todd made that patch that fits between the outdoor grass walls, and the ice set in DD that looks very similar but with terraces you can walk on.

So I'm wondering if From' provided a tool for that, or if you just eyeball things, or what??