Why Would Subregion do This?

[artitech]

I created a subregion of asphalt and for some reason my "grass" surface is creeping in on it, see attached image, showing the boundary I have used for the subregion, although the asphalt isn't actually adhering to it?

Why would this be occurring?

[Max Lloyd]

I've had this one as well. Have you got 2 subregions overlapping? (possibly where the yellow path intersects?) This tends to throw it out. If you want the yellow path to be broken by your new surface, divide the path in 2 first. To test this, finish your surface allowing it to appear incorrectly, then temporarily delete the subregion for the path. I suspect your new surface will now appear correctly.

If not, try doing the sub-region in 2 parts. Sometimes when they are too big and complex they run into problems.