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In article <1992Oct29.151010.7244@Princeton.EDU>, bdavis@phoenix.Princeton.EDU (William Davis) writes:
|> From: bdavis@phoenix.Princeton.EDU (William Davis)
|> Newsgroups: comp.graphics.explorer
|> Subject: Isosurfaces of data points scattered in space?
|> Date: Thu, 29 Oct 92 07:10:10 PDT
|> Organization: Princeton University
|> Lines: 36
|> Originator: news@nimaster
|> Nntp-Posting-Host: phoenix.princeton.edu
|> 
|> I have a file with data points scattered in 3-D space (ground water
|> polution values from wells).
|> 
|> For example:
|> 
|> 7
|>       X            Y            Z            F
|>    9.0000       49.750       57.000       95.000
|>    8.0000       49.000       56.500       2500.0
|>    6.5000       54.250       62.250       5.0000
|>    10.000       47.500       42.000       290.00
|>    9.7500       47.500       54.500       1400.0
|>    9.0000       48.750       32.500       4.0000
|>    9.2500       49.000       53.500       170.00
|> 
|> (My case actually has 71 points)  I was able to use a routine
|> (ReadXYZData, downloaded from swedishchef.lerc.nasa.gov) to convert
|> this file to a 1-D  curvilinear lattice.  I want to make isosurfaces,
|> etc. Is there a way to do this?  I can use LatToGeom and Render to see
|> the points floating in space, or connected with lines.
|> 

Try ReadXYZData -> Triangulate3D -> IsosurfacePyr -> Render

Triangulate3D is on the ftp site and will generate a pyramid of tetras 
using a 3D voronoi method. 

|> I tried to use "Interpolate", with the "Interpolation Pts" lattice
|> from GenLat.  Even though I scaled my input data coordinates to fall
|> between 0 and 63, and selected a "Coord Range" in GenLat to vary
|> between 0 and 32, "Interpolate" tells me all the points are outside
|> the range.
|> 
|> Thanks in advance.
|> 
|> ---------------------------------------------------------------------
|> Bill Davis                  | INTERnet:  bdavis@pppl.gov
|> PPPL; P.O. Box 451          | BITnet:    bdavis%pppl.gov@cunyvm
|> Princeton University        | else,      bdavis@phoenix.princeton.edu
|> Princeton, NJ 08543         | Phone: (609)-243-2546     FTS: 340-2546
|> ---------------------------------------------------------------------
|>  

-- 

Gary Griffin			I just hope I'm still dreamin'
gary@sgi.com			'cause if this is for real
				I'm gonna get very depressed
Think WORLDWIDE		
						Howard T Duck

In article <1cphg1INN73e@fido.asd.sgi.com> gary@sgi.com writes:
>In article <1992Oct29.151010.7244@Princeton.EDU>, bdavis@phoenix.Princeton.EDU (William Davis) writes:
>|> I have a file with data points scattered in 3-D space (ground water
>|> polution values from wells).
>|> 
>|> For example:
[example deleted]

I am also trying to get an isosurface of points scattered in 3-space.  Mine is
data from a body of water.

>Try ReadXYZData -> Triangulate3D -> IsosurfacePyr -> Render
>
>Triangulate3D is on the ftp site and will generate a pyramid of tetras 
>using a 3D voronoi method. 

I have tried using Triangulate3D but it always exits and prints:
Triangulate3D: connect_tetra failed!

What data would cause it to print this message?  Has anyone else encountered
this problem?

Thanks,
Harry

-- 
          hcp@csx.cciw.ca           | This message    | It takes all kinds,
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------------------------------------| PUBLIC DOMAIN.  | This thought in mind,
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In article <1992Nov3.200044.3833@csx.cciw.ca>, hcp@csx.cciw.ca (H.C. Pulley) writes:
|> In article <1cphg1INN73e@fido.asd.sgi.com> gary@sgi.com writes:
|> >In article <1992Oct29.151010.7244@Princeton.EDU>, bdavis@phoenix.Princeton.EDU (William Davis) writes:
|> >|> I have a file with data points scattered in 3-D space (ground water
|> >|> polution values from wells).
|> >|> 
|> >|> For example:
|> [example deleted]
|> 
|> I am also trying to get an isosurface of points scattered in 3-space.  Mine is
|> data from a body of water.
|> 
|> >Try ReadXYZData -> Triangulate3D -> IsosurfacePyr -> Render
|> >
|> >Triangulate3D is on the ftp site and will generate a pyramid of tetras 
|> >using a 3D voronoi method. 
|> 
|> I have tried using Triangulate3D but it always exits and prints:
|> Triangulate3D: connect_tetra failed!
|> 
|> What data would cause it to print this message?  Has anyone else encountered
|> this problem?
|> 

The Known Problems says :
     KNOWN PROBLEMS
          The program  may  fail  if  four  sites  in  the  input  are
          coplanar, or if five sites are on a common sphere.

Did you try selecting the Jitter option to jitter the points to avoid the 
coplanar issues? It may or may not help. 


-- 

Gary Griffin			I just hope I'm still dreamin'
gary@sgi.com			'cause if this is for real
				I'm gonna get very depressed
Think WORLDWIDE		
						Howard T Duck