Just a thought...
I found this DXF(Autodesk) format as popular, and can be imported in many CAD softwares.
In this link
LINK, it was discussed some CAD file structuring. Maybe someone could explain or interpret this in simpler way.
We need to decide which file format/structure to use for our simple 2D CAD program. Any other ideas or suggestions?
I've found this
PowerCAD CE demo version for Windows PPC. Can be one of our guide.