NumberWan

Typing "levelshot" in the Console could also make the trick, it automatically removes HUD and others things, but "notarget" and 1st person view are required as well. Mught not work properly with new resolutions though.

In case of this method you're more likely to make a more pristine levelshot for your map 

An intersting thing, I've never tried it. Even though I would always follow most of the rules, like making portals, adding misc_model_breakables, using detail brushes instead of structure ones where possible, dividing the map into separate areas, etc.

As I understand – you suggest adding Caulk brushes outside your visible/playable area and thus fill in the voids outside your map in order to make the whole space (used in Radiant) to look like a cube.

On 2/2/2021 at 4:24 PM, SephFF said:

Wish I could remember where I learned that. @mjt was it you? What i do remember was looking at vis and I noticed no vis cubes where caulk was....So i got the idea to just fill things with caulk and it really does speed things up.

Maybe you could make some screeshots of your progress?
Even though AngelModder posted pictures, it would be nice to see how this method worked for you.  

On 2/4/2021 at 4:59 PM, SephFF said:

This work?

That looks great! Still I'm surprised, game tools didn't take so many things into account.
I know they never planned the game to live up so long and never intended to create anything too complicated.