Yep, for me it is very usefull, and you explained the stuff very well, very well indeed
As I am doing a SP Mod, and I will do all maps from scratch, but I never built a good map for SP, only Multiplayer ones for fast game (not very detailed).
That "merging polys" thing, I didn't ever noticed that function existed.
The "semisolid" thing, I always hear that semisolid brushes are a pain on the ass, which concerns to BSP Holes and HOMs, and it's better to use solid ones. But if you say that semisolid brushes are better for curved brushes, I will take your advice
Good tutorial there
![goodjob :gj:](./images/smilies/goodjob.gif)