BrianKitts

I've been using V-ray for about a year and I am getting to the point where I know the settings well enough to crank down what i need for optimal time vs. quality. But the one thing that has eluded me is the benefits of doing a single prepass versus multiple prepasses. I normally don't have that much of a breakdown with shadows, or splotchyness (new word for webster) that I can't control with adjusting subdivisions.

So the question is, what is the benefit of multiple passes.... is there something I'm overlooking or not seeing, I've been pretty happy with the renderings I've been getting on one pass.

attached is my latest single pass rendrering - C&C also welcomed

thx in advance for your opionions -bk

Attached Images

PICU_01.jpg (99.6 KB, 280 views)

STRAT

i usually render in a single pass too. i find a layered pass is usefull for ammending shadows or gi or reflection properties for example.

i too would be interested to hear other people's experiences why they multi pass. it certainly isn't for speed. large render houses like ILM and Weta do it as standard.

nice image btw. i'd just lessen the gi bounces slightly.

ihabkal

single pass here too. With animations I think multi pass helps more becasue rerendering the animation becasue you want darker or lighter shadows would make you miss the deadline. if you can do it for renderings why not? but I really haven't seen the necessity for that except on 1% of the projects.

Victor Erthal

I thought the muli-passes were used to get the best quality versus speed. Since it would only pass with a higher resolution where needded, instead of doing it on the whole image. But i guess i'm wrong. Dit it really render faster that way?

ihabkal

some plugin renderers re render the whole scene and extract from it reflections, then rerender the whole scene and extract from it specularity and then rerender the whole scene and extract from it shadows and then rerender the whole scene and extract from it beauty pass...etc.. kinda like my post : AWKWARD
I think Brazil is like that. haven't tried Vray...Max scanline does all in one render.
update. just tried mental ray and it renders each pass by itself. for ten different pass types it renders ten times. but it is fast in those that contain little info.

Sawyer

Just to clarify - you are talking about prepasses ("currently calculating prepass 1 of 4) not effects (reflection, z buffer) passes right?

Victor Erthal

at least i was talking exactly about that. the irritating prepasses.

ihabkal

that is as confusing as you might think it is

Hao La

Dirtmap is another solution , isn't it ?

Craig Ramsay

Hmmm i'm a little confused as to what you guys are talking about. If you mean multi layered passes then personally I only really use them for photomontage work where I may need to blend in shadows or reflections to match the photograph. If my renders are completely CG then I hardly ever need to use multi layered passes.