1 - Mental Ray's Final gathering method versus the Arnold renderer.

YES indeed, Mental Ray�s Final Gathering method used alone can achieve exactly the same result as the Arnold Renderer.

Above : On the left, an Arnold rendering of the Audi TT. On the right, an XSI rendering of a Bugatti that mimics the same coloured diffuse lighting.

Original rendering : 147,000 polygons ; 900 x 676 ; 1h20' (dual-PIII 733) ; FG Accuracy = 200 / Max rad = 0.04 Min rad = 0.01

When I saw some Arnold images at the first time, I was too dazzled to see something evident : most of these images show always the same circumstances, the same simple and particular lighting situation, that is geometry in the middle of nowhere (under a perfect diffuse lighting "sky") and no direct light casting shadows.

What fooled me were two other examples (two movies) closer to pure interior situations. Therefore, I assume that Arnold was able to handle with the same quality and speed performance any lighting situation, even including Interior and artificial lighting (perhaps it can, I'm not so sure now!). The first movie is indeed the one Luc-Eric mentioned, "OnlyOneLight", and the second one is this "Pepe" character with the Droid in a sky lighted workshop which is really interesting anyway.

See them at https://www.3dluvr.com/pepeland/

Above : snapshots of 2 Arnold little movies, showing more "complex" lighting situation.

In the first case, I should have asked myself why it is so small and so noisy ? Luc-Eric wrote : " it looks like it was rendered in a different way it shows the result of a very standard GI rendering." Luc-Eric is right, under these circumstances (artificial lighting or sunlight entering through a small window), Arnold is perhaps also condemned to use other algorhytms and spend very long rendering times to achieve realistic lighting effects.

In the second case, this sky lighted workshop can more or less be compared to the AudiTT rendering situation. That is, the walls of the workshop become the sides of a box with no top, a constant diffuse sky above and a regular infinite light casting shadows inside to fulfill the illusion. Not really something more than objects in the middle of nowhere.