<html>Dear colleagues,<br /><br />I could not easily describe the problem.<br /><br />A rectangular slab step file that I have generated, attached CG1.step, shows the top and bottom surfaces inward normal.<br />I am not able to reverse this.<br />But the surface is there, see Pic1.png. When I create an STL mesh with GMSH gmsh-4.5.6-Linux64/bin/gmsh<br />these 2 surfaces are not meshed. Can you please help me understand and solve this problem?<br />Many thanks for reading.<br />Kind regards,<br />Zuheyr</html>