That article is pretty interesting. If I was doing a portal based engine in C/C++/DX/OpenGL I would definetly try that one out. I had attempted to do a BSP compiler in blitz, but got lost in the code (ie: lack of design docs ). It would be soooo much easier to do BSP stuff in blitz code if Mark didn't have something agaisnt C style pointers for Blitz. The thing that scared me a bit off the hand from that article is the tolerance bit. IHMO, the whole method in the article is getting to complicated to be feasibly programmed in blitz. AGAIN, that's my "IMHO". Anyhow, it would definetly be interesting if somebody did spent the time and labor to get all of that to work in blitz. But there is no K.I.S.S. in that... in which I am after. :)