def compute_minimal_distance_between_cubes():
    """ compute the minimal distance between 2 cubes

    the line between the 2 points is rendered in cyan

    """
    b1 = BRepPrimAPI_MakeBox(gp_Pnt(100, 0, 0), 10., 10., 10.).Shape()
    b2 = BRepPrimAPI_MakeBox(gp_Pnt(45, 45, 45), 10., 10., 10.).Shape()
    display.DisplayShape([b1, b2])

    dss = BRepExtrema_DistShapeShape()
    dss.LoadS1(b1)
    dss.LoadS2(b2)
    dss.Perform()

    assert dss.IsDone()

    edg = make_edge(dss.PointOnShape1(1), dss.PointOnShape2(1))
    display.DisplayColoredShape([edg], color="CYAN")
def minimum_distance(shp1, shp2):
    '''
    compute minimum distance between 2 BREP's
    @param shp1:    any TopoDS_*
    @param shp2:    any TopoDS_*

    @return: minimum distance,
             minimum distance points on shp1
             minimum distance points on shp2
    '''
    from OCCT.BRepExtrema import BRepExtrema_DistShapeShape
    bdss = BRepExtrema_DistShapeShape(shp1, shp2)
    bdss.Perform()
    with assert_isdone(bdss, 'failed computing minimum distances'):
        min_dist = bdss.Value()
        min_dist_shp1, min_dist_shp2 = [], []
        for i in range(1, bdss.NbSolution()+1):
            min_dist_shp1.append(bdss.PointOnShape1(i))
            min_dist_shp2.append(bdss.PointOnShape2(i))
    return min_dist, min_dist_shp1, min_dist_shp2