Florian Brucker wrote:
> Nevertheless it's annoying that a degenerate cylinder causes a parse 
> time error and not a warning. Degenerate triangles, spheres and boxes do 
> not trigger errors (in fact they're not even triggering warnings), 
> whereas an empty mesh throws an error, too. Is that really necessary? 

Not really, but it certainly was a deliberate choice at the time. Not one I 
personally think was the best, but things like this happen.

> What's the problem with ignoring those objects at parse time?

The errors are for some (did not check all) of these cases due to POV-Ray 
precomputing some values to increase speed of intersection tests right after 
parsing the object. It then detects the object is degenerate and instead of 
deleting the invalid object plus issuing a warning, it generates an error 
because rendering would most certainly fail if the object would be left in 
the scene.

Some of these annoyances have already been addressed in POV-Ray 3.7 betas, 
some more are marked on the POV-Team's internal (well, source code comments, 
not more so far) todo list for 3.7 and others won't make it for 3.7 to get 
improved. Eventually, I suppose all errors should be detected at parse time 
(there are even some detected at render-time!) and issue warnings or 
possible errors (which are non-fatal) and delete the offending object from 
the scene and continue by default,. Of course, other options making this 
still a fatal error might be useful, too, such that nobody wastes days 
rendering a scene just to discover an object is missing due to a typo that 
made in degenerate, and the final image is useless.

	Thorsten

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