// This call says I am a child to region zero in a mega-region. 'pScene' is that
// of region zero, 'offset' is my offset from regions zero's origin, and
// 'extents' is the largest XY that is handled in my region.
public override void Combine(PhysicsScene pScene, Vector3 offset, Vector3 extents)
{
TerrainManager.Combine(pScene, offset, extents);
}