hi. i've the same problem... i could'n t find any good source of info on hl bsp. so i started hacking and reverse engineering a map thinking that it shouldn't be so different from q1 bsp. i also looked in the hl sdk for code and that can help. i've loaded vertexes, and others stuff, (lumps are in different orders than in q1 bsp). if someone is working on the same problem feel free to contact me to change ideas and hints.