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ptc-31745051-Visitor
1-Visitor
January 24, 2015
Question

plotting an abitrary polyhedron

  • January 24, 2015
  • 2 replies
  • 3473 views

I have MathCad 14.0 and would like to plot a 3-D polyhedral surface from a set of (x,y,z) vertices. I could not find any plotting option/function to this - am I missing something? Does MathCad 15 have this functionality?

2 replies

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RichardJ19-Tanzanite
19-Tanzanite
January 24, 2015

There is nothing built-in, but if you download and install this e-book you will have more functions for plotting polyhedra than you know what to do with

http://communities.ptc.com/community/mathcad/mathcad-usage/blog/2010/05/27/creating-amazing-images-with-mathcad-14

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Werner_E25-Diamond I
25-Diamond I
January 25, 2015

chris jekeli wrote:

I have MathCad 14.0 and would like to plot a 3-D polyhedral surface from a set of (x,y,z) vertices. I could not find any plotting option/function to this - am I missing something? Does MathCad 15 have this functionality?

I can't have that functionality because a set of vertices does not describe a surface! You would have to provide the information which vertices form an edge and which a tile. Being no 3D CAD software Mathcad's posibilities are limited and a surface is built by quadrilateralso only. But the "Amazing Images" E-Book Richard pointed you to does more most of us where aware that could be done.

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RichardJ19-Tanzanite
19-Tanzanite
January 25, 2015

a set of vertices does not describe a surface!

In general that is of course true, but are you sure it's true when the surface is specified to be a polyhedron? If the surface is a polyhedron then I think the vertices must be on a 3D convex hull, and that is enough to determine the edges. I may well be wrong about that though, because I certainly do not have any proof

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Werner_E25-Diamond I
25-Diamond I
January 25, 2015

Richard Jackson wrote:

a set of vertices does not describe a surface!

In general that is of course true, but are you sure it's true when the surface is specified to be a polyhedron? If the surface is a polyhedron then I think the vertices must be on a 3D convex hull, and that is enough to determine the edges. I may well be wrong about that though, because I certainly do not have any proof

I am not sure, either, but I guess you are assuming that the polyhedron is simply connected and convex, which was not stated by the OP. This does not mean, though, that I would know of a simple way to create the necessary data structure in MC for a convex polyhedron.

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