All; I created what I thought was a closed volume, but GMSH doesn't agree. I've attached the offending file, does anyone know why it's not working? Regards, ...Dan -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: gun1.geo URL: <http://www.geuz.org/pipermail/gmsh/attachments/20090608/0ccb7b65/attachment.geo>