Cutting brushes is relatively cheap, don't worry about polygon totals on your world geometry. Props and details, down the road, will be a much bigger drain on your fps.
So slice and dice all you need to get stuff to fit.
The Following User Says Thank You to xzzy For This Useful Post:
No problem. Just so you know, generally the Mapping Discussion forum is the best place to ask for help, this is more for requesting specific things like models or materials.
Also, it's usually better to build rather than cut. Especially when you're making something like the ground, which is going to be broken up into a zillion pieces anyway.
[Help] "Cutting"
