Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!rpi!batcomputer!eric
From: eric@batcomputer.tn.cornell.edu (Eric Fielding)
Newsgroups: comp.lang.postscript
Subject: Re: Drawing lots of triangles
Message-ID: <9566@batcomputer.tn.cornell.edu>
Date: 18 Jan 90 17:03:06 GMT
Reply-To: eric@geology.tn.cornell.edu
Distribution: na
Organization: Department of Geological Sciences, Cornell University
Lines: 24

In a recent article BatchelderN@hannah.enet.dec.com wrote in response to my
query: 

>> I have a picture that consists almost entirely of 180,000 filled
>>triangles.  (This is the output from a 3D rendering program.)

Thanks for your suggestion to use 'load' instead of 'def'.  I am going see if
I can try that.

>As an aside, for those of us out here who are curious, could you give us
>a short description of what this thing you're drawing is? (I'd like to
>know about the boxes one too!)
>Ned Batchelder, Digital Equipment Corp., BatchelderN@Hannah.enet.DEC.com

The triangles are rendered topography with a light on the surface.  The topo
data is actually a grid of 1200x1200 elevations, but I subsample it to 
300x300 (x 2 triangles per grid cell) before rendering it to make feasible.  If
I was a graphics whiz, I can see that it would be much more efficient to use
a ray-tracing approach, since at the (dithering) resolution of the LaserWriter,
there are fewer pixels than triangles.  A bitmap of the output would be much
faster to print, but I am using a graphics package that does not have that
option.

				++Eric Fielding