Re: Delaunay and Java3D

• To: Bill Hibbard <hibbard@xxxxxxxxxxxxxxxxx>
• Subject: Re: Delaunay and Java3D
• From: Desiree Hilbring <hilbring@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
• Date: Wed, 23 Aug 2000 12:00:33 +0200 (MET DST)

Hi thanks for your help, VisAd is working now, and I tried to implement
your hints.
So after the Triangulation I get an object terrain (class FlatField), how
does the geometry of this object looks like? 
For implementing some Java3D-Objects for my application, I guess I need
some information about triangles, so that I know these coordinates go
together to build a triangle for building a 3D-object.
Sorry I am not experienced with Triangulations, am I wrong?
How would I got to build my 3D-obejcts?

Thanks Desiree



o------------------------------------------------------------------------o
| Desiree Hilbring      Institut fuer Photogrammetrie und Fernerkundung  | 
|                       Universitaet Karlsruhe, Germany                  |
|                                                                        |
|                       email: hilbring@xxxxxxxxxxxxxxxxxxxx             |
|                       # 0721 6083676                                   |
o------------------------------------------------------------------------o

On Tue, 22 Aug 2000, Bill Hibbard wrote:

> Hi Desiree,
> 
> > I am developing an Java3D Application, where I want to create a
> > terrain-surface from discrete Points. I have seen that the API from VisAD
> > includes some classes about Delaunay-Triangulation, but I do not have a
> > clue, how to use them, or if they can be helpful for me. Where can I find
> > more documentation, as in the API or even some examples?
> > Thanks for any help in advance.
> 
> Assume that the locations of your points are defined in two
> arrays:
> 
>   float[] x_locations, y_locations;
> 
> and the terrain heights at these points are defined in the
> array:
> 
>   float[] heights;
> 
> Then you can create a terrain as a FlatField like this:
> 
>   RealType x = RealType.getRealType("x");
>   RealType y = RealType.getRealType("y");
>   RealType height = RealType.getRealType("height");
>   RealTupleType xy = new RealTupleType(x, y);
>   FunctionType terrain_type = new FunctionType(xy, height);
> 
>   Irregular2DSet set
>     new Irregular2DSet(xy, new float[][] {x_locations, y_locations});
>   FlatField terrain = new FlatField(terrain_type, set);
>   terrain.setSamples(new float[][] {heights});
> 
> Note that the 'new Irregular2DSet' constructor will implicitly
> invoke one of the Delaunay constructors to compute a topology
> for your x and y locations.  You generally only need to invoke
> a Delaunay constructor explicitly when you are constructing a
> DealaunayCustom from a known topology.
> 
> Please let me know if you have questions about this.
> 
> Cheers,
> Bill
> ----------------------------------------------------------
> Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI  53706
> hibbard@xxxxxxxxxxxxxxxxx  608-263-4427  fax: 608-263-6738
> http://www.ssec.wisc.edu/~billh/vis.html
> 

• Follow-Ups:
  • Re: Delaunay and Java3D
    • From: Bill Hibbard

• References:
  • Re: Delaunay and Java3D
    • From: Bill Hibbard