Well, I have a similar problem and I did not actually get it. I have a vehicle and a terrain with hills and slopes. I want to make this vehicle always stay perpendicular to the surface. I tried to use c_trace and vec_to_angle and normal but the vehicle looks with its x axis to the surface instead of z axis. So how can I make the vehicle be always perpendicular to the surface at an angle or slope of the terrain?
Thanks.