Hey!
Since the project idea originally comes from me, I thought I'd chime in give a little perspective. We've been talking about completely moving to Cairo for quite a long time, and yet we've made just first steps towards that goal. This project could be an interesting playground for our expansion into the world of GPU accelerated rendering *and* it would help those of us who do technical drawing and deal with all sorts of 3D data.
Using a 2D graphics library to do the outsourced 3D preview seems a bit unusual to me, but why not - sounds interesting - The only consideration would be that while Cairo-gl will do the rendering very fast, the task of getting from 3- to 2D (aka transformation stuff & perspective projection) would be left to me and consequently be done without hw-acceleration. That's terribly expensive, so I doubt it will result in a fluently movable preview for meshes with more than a few ten-thousand polygons. But I have no numbers yet. I'll try it and report back.
It would be absolutely great if somebody wanted to be a potential mentor for this project idea ;-)
Bye, Alex
Side note: Assimp/Open Asset Import Library (for those who don't like the first name) is steering towards another stable release in late April.