Terrain Map Borders

Other then building of a terrain wall of sort does anyone know how to make it so units are force to stay on the terrain model with out running off the edge?

1 - you can use vertical walls where the edges of your terrain is (invisible collides, plane types)
2 - make a system with raytraces in front of your units direction to check for terrain
3 - If your terrain has a fixed size, forbid the units to go to distances > size of your terrain - epsilon (so that they don’t reach the edge).
There are probably other solutions too

Excellent thank you this will help we will research and talk about them all to see what solution works best for us.