View Full Version : Vray Irradiance Map - Similar to MR FG point cache?

07 July 2010, 03:24 AM
Hey guys,

*a brief run through of the scenario - Lets say I have a huge scene with trees, roads/grass fields & buildings and I need to render it all with no flickering and am using Global Illumination. The animation sequence will potentially be 4500 frames long

Previously, with Mental Ray, i'd do a Final Gather Point cache prior to rendering. It really solved my flickering issues and didn't take TOooo long. Like a day and a half. After which, I could easily just put the trees, buildings and grass fields on separate layers and render. Computer seemed to *remember* all the objects that were there and did the appropriate GI render.

Now with Vray, I used this tutorial which is the LightCache saving of the map followed by irradiance map. This generally works and have given me great results in fighting flickering .Tutorial (

Currently the Light Cache is fast and light to create. That seems to render pretty alright but the irradiance map takes foreverrrrrr and I am wondering if I were to break up the layers later, will it function similar to the point cache system in Mental Ray. It seems to *actually* be rendering which takes forever, no final image but the prepass 4 of 4 is damned slow. Seriously have you guys done this before? Is there a way to speed it up?

Thanks - Maya2010 and Vray 1.5

I hope Vlado sees this =) pretty please Vlado. Oh chaosgroup, I've emailed you the question

07 July 2010, 03:26 PM
Did you try to use the different modes? Like the incremental add to current map?
Never tried that separating objects, usually in arch viz i render everything in one go.
What i do to have some control in post is generate what i call auxiliary passes, like Zdepth, ID etc .

07 July 2010, 03:37 PM
Another thing to notice, is that some modes will not work with DR (distributed bucket render).
You will have flicker problem then.

07 July 2010, 07:33 PM
Hey Slipknot,

thanks for the reply. Just to add to the post for future reference for anyone else. Chaosgroup replied my email and said that it should be possible to do a light cache and then irradiance cache followed by breaking up the scene into layers prior to rendering.

As for the DR. I've done a previous test after the method I stated earlier and it seems to work =D yay!

As for the other modes. The tutorial seems to have highlighted this incase anyone might find it useful

Q: Why did you choose Multiframe incremental over Incremental add to current map mode? What is the difference between the two that would cause you to choose one over the other? I ask because Ive never used Multiframe incremental and have always used the Incremental add to current map.
A: The only difference is that the Multiframe incremental mode will delete the map in memory at the start of the rendering. With the Incremental add mode, the current map is not deleted.

07 July 2010, 04:12 AM
Hey guys, Anyone else tried irradiance maps and all that?

My scenes about 500mb so I can't upload it to them to take a look but it sure takes a lot longer/frame then MR with point caching prior to actually working on the final render. =(

It was pretty decent when rendering trees. But this time, its slow as hell! =(

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07 July 2010, 04:12 AM
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