Cab: point of origin
To have the cab wall correctly positioned its 0,0,0 point has to be matched with the 0,0,0 point of the truck chassis that will accept the cab wall.
Chassis: point of originAny (local) truck chassis designed to carry a body construction and destined to visialize a cab wall should have its 0,0,0 point at the intersection of the chassis centre line, the front axle centre line on the level (outer edge) of the lower flange of the chassis main longitudinal profile.
See Figure 2.
Check any of the 2D-DXF chassis layout drawing for visual reference to the chassis origin point or the chassis position test file.
The air intake pipe is positioned the same way as the cab wall.