If you use the sandbox tools to make the terrain, SU will automatically place the terrain within a group. However, the script requires the terrain to be active - not in a subgroup. So you must either explode the group or open the group and then create the path geometry.
If you use the sandbox tools to make the terrain, SU will automatically place the terrain within a group. However, the script requires the terrain to be active - not in a subgroup. So you must either explode the group or open the group and then create the path geometry.