Portal Mapping Tips Megathread
- 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.
Gonna DL HL2DM and replace things like ya said 
I'd love for them just to release it as an SDK thou, make our lives easier.
added the portal FDG and started up.
Also i have decomplied a portal bsp to see how everything works, if ya'll need help with any workings, tell me! 
If you DL them agree not to plagurize, just use them as examples :p
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Anyway, thinking about making a small map with the friendly turret, is there a place to upload maps for this site? Or should i make one that is actualy just not a single thingy.
I can actually think of a full side story experment and an alternate ending but meh 
btw, companion cube = 2nd skin on props\metal_box