Sometimes the no_image flag prevents the trace() function
from detecting an object, and sometimes it does not.
The behavior is very inconsistent, and must be a bug.
The minimal scene below demonstrates the problem.


// single sphere with no_image is detected by trace
//#declare Object = sphere {0, 1.0 no_image}

// sphere with no_image inside union is not!
#declare Object = union {sphere {0, 1.0 no_image} sphere {0, 0.5}}

#declare N = <0,0,0>;
#declare P = trace(Object,5*y,-y,N);
#debug concat("\n\nP: <",vstr(3,P,",",4,2),">   N:
<",vstr(3,N,",",4,2),">\n\n")


Tested on the following:

POV-Ray for Windows, Win98, AthlonXP 1700+, 256 MB RAM

POV-Ray for Windows, Win2000, AthlonXP 2.400+, 768 MB RAM

Rune
--
3D images and anims, include files, tutorials and more:
rune|vision:  http://runevision.com **updated Jul 25**
POV-Ray Ring: http://webring.povray.co.uk

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