As with any software, when working on a lengthy project, it is always a good idea to save several versions of your work as you go.
Originally Posted by gzairborne
Work for a while, save <project>001.ptg, work for a while longer, save as <project>002.ptg, work for a while longer, save as <project>003.ptg
All software has bugs, and there is nothing quite as soul-destroying as losing hours of your best creativity.
Having said that, we do endeavour to have as few bugs as possible!
AndyRage's mantra for graphics engine code:
"Sure - how hard can it be?"