Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2008

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: reconstruction of 3D grid with connectivity

  • To: mathgroup at smc.vnet.net
  • Subject: [mg91411] Re: reconstruction of 3D grid with connectivity
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Wed, 20 Aug 2008 06:23:23 -0400 (EDT)
  • Organization: Uni Leipzig
  • References: <g8gj4j$etq$1@smc.vnet.net>
  • Reply-to: kuska at informatik.uni-leipzig.de

Hi,

a) your assumption "when u and v  are each incremented by given ustep 
and vstep" because ParametricPlot3D[] make a irregular triangle mesh
you can see the mesh with

plt=ParametricPlot3D[{Cos[phi]*Sin[th], Sin[phi]*Sin[th], Cos[th]},
  {th, 0, Pi}, {phi, 0, 2 Pi}, Mesh -> All]

b) the connectivity can be shown with

GraphPlot[
  Union[Flatten[(Rule @@@ Partition[#, 2, 1, {-1}]) & /@
      Cases[plt, _Polygon, Infinity][[1, 1]] /. (a_ -> b_) /;
       a > b :> (b -> a)]
   ]]

Regards
   Jens

Narasimham wrote:
> For surface ParametricPlot3D[{x = f(u,v), y = g(u,v), z = h(u,v)},
> {u,umin,umax,ustep},{v,vmin,vmax,vstep}]
> 
> how to obtain the connectivity matrix (when u and v  are each
> incremented by given ustep and vstep), using Delaunay or Voronoi
> triangulations? In this case there would be curved or skewed
> quadrilaterals instead of triangles that discretizes the surface.When
> connectivity matrix and coordinate matrix are given with each  point
> ID reference number, the surface should be  reconstructed, i.e.,
> plotted, and/or Shown without again giving out the above command.
> 
> Thanks in advance,
> 
> Narasimham
> 
> 


  • Prev by Date: Re: Mathematica and Jaws
  • Next by Date: Re: Re: Solving nonlinear inequality constraints
  • Previous by thread: reconstruction of 3D grid with connectivity
  • Next by thread: Re: reconstruction of 3D grid with connectivity