- GCFscape, use this to extract files from GCF files. Very handy tool. Link: http://nemesis.thewavelength.net/index.php?p=26
- Portal FGD. Link: Removed, look in the Download Database
- Version 7.3 to 7.2 VTF converter. Link: Removed, look in the Download Database
Thanks to Snakez over at HL2World.com for these files!
I use HL2DM for mapping just about everything, but you could make a new folder and a new game config and everything if you wanted to keep stuff seperate (no reason to, just more work).
- Extract source 2007 models and materials to your hl2mp folder (not sure if this is necessary, but was for TF2 mapping).
- Extract Portal models and materials (in content gcf) to your hl2mp folder.
- Run fixvtf on the materials folder.
- Start hammer, go to config, add portal.fgd
- Think with portals!
Note: Right now I have not tested this, but this is the exact same method I used to map in TF2.

