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View Full Version : Vray animation: prepass Irradiance vs. one pass Brute Force


LML
01-25-2012, 11:44 PM
hi all

trying to get some experience with prepass animation with Vray in Maya, using Irradiance Map/Light Cache, as I've seen in some tutorials around the web.

But as I'm testing this, I'm wondering if doing a single pass with Brute Force might be nearly as quick, flicker-free, and potentially less error prone--than doing the multi-pass workflow.

(I am referring to animations with both moving camera and moving objects)

does anyone have some thoughts? or better yet, some tests, to say which is a better method? I know there are a ton of variables, but it seems that brute force doesn't take terribly much longer, in my experience

cheers

LML

thev
01-26-2012, 07:12 AM
But as I'm testing this, I'm wondering if doing a single pass with Brute Force might be nearly as quick, flicker-free, and potentially less error prone--than doing the multi-pass workflow.Brute force is certainly a lot easier to set up and a lot more reliable. If you can afford it rendertime-wise, then definitely go with it.

Best regards,
Vlado

DanGrover
01-26-2012, 09:56 AM
Brute force is certainly a lot easier to set up and a lot more reliable. If you can afford it rendertime-wise, then definitely go with it.

Best regards,
Vlado

Definitely! It's saved us in a number of instances!

To the OP, though, I'd suggest that the amount of "bouncing" seems to drastically affect the render times for decent quality with brute force. That is to say, if you have a scene that's outdoors in nice bright sunshine, brute force will probably do it almost as quickly as a pre-calculated irradiance map. An interior lit by diffuse light from a sky light? Not unless you have a Cray! It's really about experimenting, but remember that the brute force render settings are not only affected by the bounce count and the subdivisions, but the DMC sampler settings (under the 'Settings' tab in Max - not sure about Maya!)

LML
01-26-2012, 03:50 PM
thanks to both for your response

in the case of a Brute Force workflow, is the secondary engine set to Light Cache? Or do both engines have to be set to Brute Force to eliminate the chance of flickering?

(I understand that Light Cache is view/camera dependent, so it seems as though it would also be a potential cause for flicker...)

LML

CHRiTTeR
01-26-2012, 07:16 PM
Lightcache can also cause flicker in some cases

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