Re: Volume rendering of Irregular3DSet

• To: visad-list@xxxxxxxxxxxxx
• Subject: Re: Volume rendering of Irregular3DSet
• From: gunnar.sletta@xxxxxxxxxxx
• Date: Mon, 19 Mar 2001 14:51:31 +0100

I thought that there was some general getValue(x,y,z) function in Field,
that allowed the renderer to render volume transparent of the actuall grid.
This makes it of course a bit more complex.

Why are there 6 texture plane sets, and not only 3. It was my impression
that the texture planes would look the same from both sides. Is it to
bypass the depth sorting problem in Java 3D or something?

Resampling works, but takes away much of the resolution since most of the
elements are concetrated around one area. What about boundry extraction? Is
the easiest way to simply locate all triangles on the boundry and put them
in a Irregular2DSet?

Gunnar



                                                                                
                                       
                    Bill Hibbard                                                
                                       
                    <hibbard@facstaff        To:     gunnar.sletta@xxxxxxxxxxx  
                                       
                    .wisc.edu>               cc:     visad-list@xxxxxxxxxxxxx   
                                       
                    Sent by:                 Subject:     Re: Volume rendering 
of Irregular3DSet                       
                    billh@xxxxxxxxxxx                                           
                                       
                    sc.edu                                                      
                                       
                                                                                
                                       
                                                                                
                                       
                    19/03/2001 11:56                                            
                                       
                                                                                
                                       
                                                                                
                                       




Hi Gunnar,

> I've constructed a Irregular 3D set and I want to view it, and I used the
> same approach as for Linear3DSet, where I simply enabled textures, and it
> produced the slice planes automatically. I couldn't make this work for
> irregular sets.
>
> Do I have extract each triangle/tetrahedra and make sets out of them as
> done in Delaunay.main or is there some simpler way of doing this?

Actually, VisAD volume rendering is more complex than the
Delaunay.main() logic. Volume rendering from Linear3DSets
creates six different sets of transparent faces and switches
between them as the volume rotates. There is no good way to
do this with Irregular3DSets or even Gridded3DSets.

Your best bet is to resample your Field to a Linear3DSet
that covers the same volume as your Irregular3DSet.

Good luck,
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: Volume rendering of Irregular3DSet
    • From: Bill Hibbard