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From: Kessells_SR@cc.curtin.edu.au
Newsgroups: comp.graphics
Subject: Re: triangulation and contouring
Message-ID: <3124.26cc0245@cc.curtin.edu.au>
Date: 17 Aug 90 06:42:13 GMT
References: <1990Aug15.003127.22609@NCoast.ORG>
Organization: Curtin University of Technology
Lines: 40

In article <1990Aug15.003127.22609@NCoast.ORG>, atul@NCoast.ORG (Atul Parulekar) writes:
> I think there was a discussion some time back about delaunay triangulation of
> random points.  I wrote a program to do this based on a paper by Cavendish JC,
> Field DA, Frey WH in the International Journal for Numerical Methods in 
> Engineering, V21, 1985, but it ran too slowly (I have seen programs which run
> 5-10 times faster).  Is there any fast (fastest ?) algorithm to do this?
> 
> Also, I would like to include breaklines in the data.  (These are lines which
> cannot be intersected by any triangle, i.e., the lines are a part of the
> triangulation.)  Any suggestions?
> 
> Finally, any suggestions on how this triangle network can be used for 
> contouring directly (i.e., without first generating a grid of regularly
> spaced points)?

I have developed a 2D Delaunay-based triangulation system with breaklines etc.
The system has been running with a commercial package (no strings) and been 
hammered quite a bit without failing (as yet!).

On a 12mhz 286 with 287, it can do about 1000 points in 50 sec. 386= got to
about 19 secs. IRIS blinks ... It is based on Lee & Scachter's work, but
bits are from everywhere.

It was written as a 3rd year project and I am currently working with the 3D
problem for honours. So I would like to hear from all who are interested.
Also, I have a friend working in representing the surface to varying
degrees of accuracy for his honours thesis....

The my code plus report is freely available to anybody who asks (no strings 
except for a little recognition).

					Michael

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