[Brlcad-tracker] [ brlcad-Bugs-1204586 ] rcc joint boolean produces visual artifacts

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Bugs item #1204586, was opened at 2005-05-18 18:19
Message generated for change (Comment added) made by lbutler
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Category: Raytrace
Group: unexpected behavior
Status: Open
Resolution: None
Priority: 5
Submitted By: Sean Morrison (brlcad)
Assigned to: Nobody/Anonymous (nobody)
Summary: rcc joint boolean produces visual artifacts

Initial Comment:
If two cylinders are joined at a right angle and unioned togeter with 
exactly their overlapping portions subtracted with boxes, you end up 
with visual artifacts in the rendering.  There are two primary 
artifacts evident, the first being that the boolean evaluation of both 
cylinder ends appears to slice a very small portion out of the 
cylinder edge where the other cylinder numerically matches it.  That 
is, where the flat cylinder top is tangent to the other cylinder's 
curved side surface.  The second artifact appears to be a speckling 
rim where the cylinder surfaces meet along a curved survace line.  
This results in a dark speckled line that is probably due to incorrect 
normals.

Both problems are probably due to floating point errors in the 
boolean segment calculations.  Attached should be an example 
geometry database and a saved view that easily exhibits the 
problem.


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>Comment By: Lee Butler (lbutler)
Date: 2005-06-14 17:00

Message:
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What platform (CPU and OS) are you using?  It would be nice to be able to 
reproduce this.

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