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View Full Version : VRAY render times with particles vs. scanline


jabbermacy
03-24-2007, 03:46 PM
OK,

WHY can scanline render a ton of particles in a flash and VRAY chugs and chugs and chugs and FINALLY gets it done a minute later? I'm using default VRAY (1.5RC3) options, BTW. Can there really be such a huge hit to render particles??? Is there some secret to improving particle rendering in VRAY?

depleteD
03-24-2007, 09:29 PM
From what I understand, VRay has to translate the max scene information into data that it understands.

I have the same problem with mental ray.

Scanline is the fastest cause it natively understands the particles.
I think brazil is better for this aswell. Its been awhile since I've used Brazil unfortunatley

What I recommend is render particles with scanline along with appropriate shadow and reflection passes and composite into your VRay scene.

Hope this helps.

-ANdrew

charleyc
03-25-2007, 01:51 PM
Actually the scanline renderer also translates geometry (converts everything to mesh) before rendering. The speed problem primarily has to do with the type of render. The scanline renderer uses a very different method to generate an image than a raytrace renderer would. Pretty much all raytrace renderers (VRay, Brazil and mental ray) will be slower than the scanline as long as the memory holds. The speed and quality of the raytrace renderers image sampling can also impact render time.

PsychoSilence
03-25-2007, 02:23 PM
we had some dicussions about vray and flow pver there at orbaz.com already...my personal advise is simply not to use vray for particle passes unless itīs neccessary.

an excerpt of the disussion:

i had SEVERAL problems using VRay 1.5x !!! one of them (a material problem as well...) is displayed as a thread in the bug report. but thatīs nothing oleg can fix. the chaosgroup should be your target of complain. i posted this in the chaosgroup forum but never got a proper workaround for several problems i ran into...

next question is what version of box#1 do you run? there where several updates in the past. current version 1.66:
http://www.orbaz.com/forum/viewtopic.php?t=28

my personal advise is stay away from vray for particle passes!!! is there a desperate need for using vray? like SSS glossy funky what ever materials and whatnot? scanliner works like a charme for me in most cases. fast, easy to use...GI is easy to fake with e-light e.g. if thatīs the point for using it.

if you like share the file and i have a brief peak on it. i have vray, box#1 and box#3 on my workstation at work...

kind regards

anselm

complete discussion can be found here:
http://www.orbaz.com/forum/viewtopic.php?p=5330#5330

and a bug report i wrote back in the days:

http://www.orbaz.com/forum/viewtopic.php?t=813&highlight=vray

hence it follows: vray is very nice (and once it was fast too!!!) for architectual visualisation and automotive image films but for serious vfx use scanliner or another package :D

cheers

anselm

charleyc
03-26-2007, 08:05 AM
Yeah, the problem is that scanline can fall short pretty quick with too much geometry (too many particles, or shape instanced mesh). And not all the other renderers will correctly motion blur the particles. VRay allows you to use an Image MB and get a lot more particles to render than the scanline if you need it...at a cost of speed. Brazil 2 handles the motion blur correctly and actually has a bit faster or better image sampling that VRay seems to, but Brazil 1 does not. I think this is really why Krakatoa will be a success. It will fill a small gap in a big way.

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03-26-2007, 08:05 AM
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