Opening PTG files in a different version of ArtRage
Yes. All versions of ArtRage, including the iPad and the Demo, create PTG files and can open and edit these. So any paintings you create in one version (e.g. the Demo) can be continued with another version (e.g. the iPad or ArtRage 4).
Note: If you import an extremely large painting to the iPad, then you may run out of memory.