The Sheen
I've gotten back into portal mapping, and I'm loving it so far. Unfortunately, cubemaps seem to be broken. This might be because my vmf directory is a little different from normal, but I'm wondering if this is a common problem with Portal now.
I have cubemap entities and I've compiled them into the map, but they still don't show up.
What I've had to do to get cubemaps working in Deathmatch is first, open up the .bsp (with PakRat or what have you), remove all texture files from it, load the map up (in-game), set mat_specular to 0, builcubemaps, set the specular back to 1, and reload the map.
Yea I've been mapping for portal 1 as well, and while I haven't tried out cubemaps yet, I have noticed that projected textures are completely nonfunctional. I honestly don't know if portal ever had projected textures working or not, but if it did, knowing how to fix this issue would be great, seeing as how the cubemaps issue seems to have a hacks solution.
Aperture Science: We do our science asbestos we can!
Thanks Ciirulean. I guess I'll compile cubemaps as a final thing.
@Camben, It's really awesome someone else still portal maps!Yeah, env_projectedtexture was never used in portal. It doesn't work for the most part. If you want sharp shadows that are similar, you can lower the lightmap scale, but portal uses soft shadows all around anyway. The lowest I usually go for walls lit by obs rooms is 10, but I would stick with 16 for the most part.
Ok thanks 
I'll also experiment with fake shadows as overlay textures (rotating fans, grate shadows, etc)
Aperture Science: We do our science asbestos we can!