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Date: Mon, 14 Dec 92 11:57:07 -0800
From: Ken Case <kc@omnigroup.com>
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To: <cfleming@alleg.edu>
Subject: Re: improving wireframe images when using Interactive Renderman
Cc: rman@aero.org

> Is it possible to increase the number of polygons used to display
> shapes generated by functions such as RiSphere() and Ri_Torus()
> when using the Interactive Renderman renderer on the NeXT?  I have
> used patch meshes to get better looking wireframe surfaces with
> Interactive Renderman, but it seems there should be a simpler way
> to do it than using meshes.

You bet!  Call RiGeometricApproximation() setting the tesselation density.   
(This is documented in QRMSpec.rtfd in the 3.0 Release Notes.)

As an example of how to do this, here's a pair of methods we use in a  
subclass of N3DCamera to control the tesselation density from a slider:

    - setGeometricApproximation:(RtFloat)divisions
    {
	RtFloat tesselationParametric[2];

	tesselationParametric[0] = divisions;
	tesselationParametric[1] = divisions;
	RiGeometricApproximation(RI_TESSELATION, RI_PARAMETRIC,
				 tesselationParametric, RI_NULL);
	[self display];
    }

    - takeGeometricApproximationFrom:sender
    {
	return [self setGeometricApproximation:[sender floatValue]];
    }

Have fun!

				Ken Case
				The Omni Group