This tip comes from Frédéric Louguet (aka Render Fred) and draws on his experience running the RANCH renderfarm.
Here is something I have added to the RANCH Renderfarm User Guide (as we had seen this problem with several customers), but I think it might be helpful to everyone. The purpose of this tip is to detect scenes which require incredibly long render times... before it is too late.
Before sending us a still image to render, ALWAYS do the following test: render your scene on your system with all the final parameters, but in 16 pixels wide (for landscape images) or 16 pixels high (for portrait images). For example if your image has a 4:3 ratio, render it in 16 x 12 pixels, Render to Screen mode.
It seems like a joke, but really it is not. For a "normal" scene, even in ultra mode, the render time should be very fast (a few seconds to a minute for complex scenes). Note: count only the render time, not the preparation time which will be the same, even in high resolution.
BUT IF THE RENDER TIME IS > 1 MINUTE, YOU ARE IN TROUBLE!
(on a Core 2 Duo @ 2 GHz for instance)
It means it could take a VERY long time on the farm in high resolution and that it would cost you a lot of money. Typical symptom for these “nightmare scenes” : Vue quickly displays 100%, but the "finished!" message appears only after several minutes.
