half-impassable grassland

[dalek master]

I wasn't sure to put this but I guessed and put it here

I have no idea how difficult this might be, but I had this idea, and I was thinking if you could have only select units move across grassland (like naval and ground units, but grassland instead of water). Im using grassland as an example.

OK if its to hard or impossible

 

[surt]

What you'd probably want to do is to create a new domain, and assign your grasslands to be in that domain instead of domain land. Then give the appropriate units the ability to move in that new domain. There may be other stuff you have to do, I've not actually tried this.

Update: sorry, bad news is that apparently terraininfo.xml doesn't actually use the domains, it just uses land/water. Maybe firaxis will fix that in a patch.