hello try something like Extrude {{0, 0, 1}, {0, 0, 0}, Pi/2} {Line{1};} to create a surface of revolution from spline 1 in addition Line{9} In Surface{32}; to force the meshing to pass trough the intermediate circle arc of course adjust the numbers -- jean pierre aubry jeanpierre[at]lamachine.fr 33 688 670 795