Yeah, reminds me of the time I had to write a BSP tree builder as a course assignment, and ending up spending 2 months writing an OpenGL renderer + an importer for the Apple QuickDraw 3D API instead (hint: don't try to do that, it's almost a full object-oriented programming language in itself if you want to support even a moderately complex model).
All just because I found some nice architecture models that were only available in QD3D format, and I was convinced it would only take me a few hours to read them... I only got the brilliant idea of just converting them to something simpler like .3DS after I already finished the assignment >_<
That is a very important lesson.