Hi Ashish, Does it help if you change the sign of every line entry number in the Plane Surface definition that is a problem?
Best regards, Mark. On Thu, May 03, 2012 at 06:23:34AM +0000, Negi, Ashish wrote: > Hi Ashish, > > > > Thanks for replying. > > > > Let me explain my problem again. I have attached 3 pictures below. First, > shows > a Tetrahedral mesh of square duct. So, all surface elements are Triangle. > Second, shows normal vectors computed using cross product if Triangle vertices > are saved in clockwise sense (in the picture). Third, shows normal vector > computed if Triangle vertices are saved in anti-clockwise sense. So, second > picture gives me outward normal which I need. > > > > I found that all Triangles do not give me outward normals if I assume > clockwise > sense (in following picture). So, I wanted to know if GMSH has some other way > to provide me outward normal for each surface Triangle. > > [cid] [cid] > > > > Thanks, > > Ashish > > > > From: Ashish Garg [mailto:[email protected]] > Sent: Wednesday, May 02, 2012 1:09 PM > To: Negi, Ashish > Cc: [email protected] > Subject: Re: [Gmsh] outward normal of surface triangles > > > > Hi Ashish > > give the condition that the cross product should be greater than zero. I guess > it will resolve the problem. > > Ashish Garg > > On Wed, May 2, 2012 at 12:38 PM, Negi, Ashish <[email protected]> > wrote: > > Hello Everyone, > > > > I?ve been using GMSH library to open Nastran BDF file and extract mesh data > for > my software. I generally load a mesh consisting of only Tetrahedra. Hence, > surface of model have only Triangle elements. > > > > I want to find outward normal at each Triangle. I get coordinates of each > Triangle and then take cross product to get normal to the element. But, I?m > not > sure if it will always be outward. Can someone suggest a solution to this > problem? > > > > Thanks, > > Ashish > > > > > > > _______________________________________________ > gmsh mailing list > [email protected] > http://www.geuz.org/mailman/listinfo/gmsh > > > > _______________________________________________ > gmsh mailing list > [email protected] > http://www.geuz.org/mailman/listinfo/gmsh -- Dr. Mark Starnes Principal Physicist FT Technologies Church Lane Teddington TW11 8PA web: www.fttech.co.uk DDI: 0208 614 2730 _______________________________________________ gmsh mailing list [email protected] http://www.geuz.org/mailman/listinfo/gmsh
