#1 - On cod if there was a side of a brush that players would not be seeing you would put the "caulk" texture on it, does HL2 also do this?

#2 - I can make a wall using the block tool, but how could i make different shapes, like hexagons ect.

Thanks

Ok found out how to do #2, anyone know the answer to #1?

Just use the nodraw texture like you used the caulk in cod.

Select the block tool 1st (shift+b)
On the right hand side in hammer look for categories/primitives objects/block were it says block use the drop down bar to select a new shape like cylinder then under that it will say faces just put in how many you want.
Some will open a new window and give you a preview of what they will look like.
Arch tool will do this good to use for a curved road.
If you have a look at this post and go to some of the tutorial links on there they will help you a lot.
http://www.modsonline.com/Forums-top-13362.html

do you use the nodraw texture? does it actually effect fps if you dont? Thanks

Have a look at this site it explains nodraw better than I could a lot of very useful help on there as well.

http://www.student.kun.nl/rvanhoorn/Optimization.htm#chapter2