I started at a company today. My first ever full-time job. I'm pretty tired (it was boring), I already slept one, I dreamt about green fields and George Bush making a speech, and some other things.
I started to code the unfolding algorithm 2 days ago. It's tough.
I have two view-modes: 3D and 2D. The 2D will be for the unfolded stuff obviously. I don't think I'll have multiple viewports, it will be more like AutoCAD softwares with the "sheet" "3D" or whatever tabs.
So, about 2D: there's a grid, it's very similar to 3d MAX's grid (accidentally...)
So: It's an infinite grid, but it's faked: I calculate the starting and ending line at runtime, so there are always a finite number of lines on the screen. I added a "level of detail effect": if the distance between two lines are smaller than a given value, the grid size will be multiplied by 10.
I did these grids in immediate mode, since the number of lines are controlled, so there will never be too many.
Video (EDIT: I don't know why the aspect ratio is fucked up, it's okay in the application)