> I'm trying to hunt down the origin of an unexpected black box in a scene.
>
> Is there something like Trace() that I can use to find out where the
> object in question is defined?  I don't care if there are 7 different
> objects overlapping, at least I'd know which 7 to look into...
>

You may have a box, or any object, that don't have any pigment. To check 
for that case, near the begining of your scene, add:

#default{pigment{rgb<1,1,0>}finish{ambient 1}}

If you now have a bright magenta box, you know that you have an object 
that don't have any pigment.


It may be caused by overlaping transparent objects. Try adding:

max_trace_level 200

to your global_settings section.


Do you have any iso_surface?
If max_gradiant is to low, you can get some dark or black blocks.
In that case, slightly moving the camera can yeld to large differences 
in the result. Move the camera lateraly or verticaly by 1 unit. If the 
black box change location/shape, it may be your problem.


If all else fails, put your objects, on at the time, into temporary 
unions. That union will contain some marker, like a green sphere set to 
ambient 1 or a text object showing some specific text. Make sure that 
this added object have a high ambient value.

During debugging, make use of the +qn options to accelerate the 
rendering. +q0 will only use pigments with full ambient lighting, 
ignoring all lights and finish items. Other values will progressively 
enable more features, starting with lights ignoring the area_light 
feature. The default for that switch is +q9.



Alain

Post a reply to this message