linear_extrude (height=3)
    import (file="chassis.dxf", layer="chassis", $fn=100);
linear_extrude (height=3)
    import (file="chassis.dxf", layer="chassis", $fn=100);
    
translate ([0,0,2.99])
    linear_extrude (height=25)
        import (file="chassis.dxf", layer="attaches-moteurs", $fn=100);