3D rendering question

• To: mathgroup at yoda.physics.unc.edu
• Subject: 3D rendering question
• From: jdock%iplab5 at yoda.physics.unc.edu (Jerry Dougherty)
• Date: Mon, 16 Nov 92 15:00:56 EST

```Question: Is there anyone out there who is working on 3D rendering?

I have a series of X-Y plots which correspond to X-Y planes along the Z-axis.

I would very much like to connect these plots together to form a region.

I have used the StackGraphics[ ] command from the Graphics`Graphics3D` package

to give myself an idea of what this region might look like, but would REALLY

like to render it in polygons.

I have been trying to use the TriangularSurfacePlot[ ] command from the

DiscreteMath`ComputationalGeometry`  package but have been unsucessful to date.

Essentially what I've done with TriangularSurfacePlot[ ] is the following:

1. For each X-Y plot I grabbed the 2D list of points from the InputForm of
the graphics object.ie.{{xi,yi},{xj,yj},...}

2. I then appended the corresponding z value to the end of each point in the
list, there by creating a list of 3D points.ie.{{xi,yi,z1},{xj,yj,z1},...}

3. I combined all the lists together to give me the desired list of points to
be connected.
ie. list = {{xi1,yi1,z1},{xj1,yj1,z1},...{xi2,yi2,z2},{xj2,yj2,z2},...}

4. I proceeded to try TriangularSurfacePlot[list] ,but my SPARC IPX goes nuts
and the process usually core dumps, not to mention all the error messages!!

5. So I reduced the problem down to two circles one with radius 1 and one with
radius 2. I assume these are X-Y planes placed at z = 3,and z = 5 resply.
Well this didn`t work either. I finally tried two triangles and had some
success but the problem is reduced to not being useful anymore.

6. I've also played around with the vertex adjacency list option but it seems
in order for the list to work properly you have to practically specify
every connection making sure to form triangles along the way,  yuck!!

Anyway  if you get anything I've said and have any suggestions what-so-ever
it would be Greatly appreciated......