surface of a convex 3d data
in [Matlab]
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From: John D'Errico on 30 Mar 2010 07:25 "adel " <adel.tekari(a)gmail.com> wrote in message <hoqfbk$3ko$1(a)fred.mathworks.com>... > > You don't want to use gridfit, griddata, etc. They are > > not designed to solve your problem. > > > > You don't even need to use the tools designed to solve > > for a general surface from scattered points that Luigi > > provides. > > > > To generate the surface of a convex set of points, you > > use a convex hull. (Seems logical to me.) Find that in > > matlab already. Depending upon the dimension of > > your problem, > > > > help convhull > > help convhulln > > > > You can display the surface using trisurf. > > > > help trisurf > > > > HTH, > > John > > Hi John and thank you for your reply > > I tried the convhulln and the output is not what I want to have > http://www.postimage.org/image.php?v=gxIFUei > (http://www.postimage.org/image.php?v=gxIFUei&code=2) > > I need a regular 3d grid and not a triangulation. > > Any help? Help? Maybe. My response is that you don't NEED a regular grid. You already know how to work with a regular grid, so you think that you need it. You don't know how to use a triangulation, so you fail to understand that it can be as useful, or even more so. Learn to use the tools available, allowing yourself to solve a larger variety of problems. Or, don't learn, and find yourself trying to drive in a screw with a hammer. John
From: adel on 6 Apr 2010 07:47
"John D'Errico" <woodchips(a)rochester.rr.com> wrote in message <hosn31$2b5$1(a)fred.mathworks.com>... > "adel " <adel.tekari(a)gmail.com> wrote in message <hoqfbk$3ko$1(a)fred.mathworks.com>... > > > You don't want to use gridfit, griddata, etc. They are > > > not designed to solve your problem. > > > > > > You don't even need to use the tools designed to solve > > > for a general surface from scattered points that Luigi > > > provides. > > > > > > To generate the surface of a convex set of points, you > > > use a convex hull. (Seems logical to me.) Find that in > > > matlab already. Depending upon the dimension of > > > your problem, > > > > > > help convhull > > > help convhulln > > > > > > You can display the surface using trisurf. > > > > > > help trisurf > > > > > > HTH, > > > John > > > > Hi John and thank you for your reply > > > > I tried the convhulln and the output is not what I want to have > > http://www.postimage.org/image.php?v=gxIFUei > > (http://www.postimage.org/image.php?v=gxIFUei&code=2) > > > > I need a regular 3d grid and not a triangulation. > > > > Any help? > > Help? Maybe. > > My response is that you don't NEED a regular grid. > > You already know how to work with a regular grid, > so you think that you need it. You don't know how > to use a triangulation, so you fail to understand > that it can be as useful, or even more so. > > Learn to use the tools available, allowing yourself to > solve a larger variety of problems. Or, don't learn, > and find yourself trying to drive in a screw with a > hammer. > > John I was finally able to make a regular mesh for my shape http://www.postimage.org/image.php?v=gxdvxSJ&code=2 http://www.postimage.org/image.php?v=gxdvxSJ |