'use irradiance map' option in materials

[flipside]

In vray material, there's an option "use IR map" which is quite usefull if you have fine detailed things in your scene on which you want to have detailed GI. If this is turned off, QMC GI is used to compute lighting on this material.

With first bounce IR map + second bounces QMC GI this is no problem. But when I use IR map + Lightcache, how do I set the subdivs for the QMC GI on the materials which have the 'use IR map' option turned off?

Or can I not use this option when using lightcache for second bounce?

Regards,

wouter

[vlado]

If you use the irradiance map, the subdivs are taken from the irradiance map Hemispheric subdivs. In all other cases, they are taken from the QMC GI Subdiv setting. You can select QMC GI, change the subdivs, and then return the previous GI engine.

Best regards,
Vlado

[super gnu]

nice tip! wish i could answer your question tho

[flipside]

thanks vlado!

[super gnu]

so.. this "use irradiance map" thing... im thinking, it would be usefiul for a flythrough with, say, moving people in... you calculate a flythrough irr. map, with people hidden, then unhide people, set materials to not use irradiance map, and hey presto, the bg is rendered with the map, and the people have nice qmc lighting on....

does it work in this way? (obviously the people wont have nice gi shadows around them, but....)

also, would be very nice if we could assign this per object too... in fact being able to use different lighting methods for different objects could be a useful tool in general.....

[Trapezium]

super gnu, sounds like wha tyou want is to just turn off generate GI for those objects.

--Jon

[super gnu]

well, no...

what i want is to generate lighting for the static parts of the scene, then simply calculate lighting locally for the moving objects (doesnt matter if the lighting desnt interact with the background..)

ive been using "add to current map" with a precalculated irr map for background (calculated with people hidden) so that for each frame, i get the lighting calculated for the moving objects, added to the nice precalculated map... reduces splotching and flickering to a minimum, whilst not taking forever to render.
however its still really slow, and since my saved irr. map is over 250 meg, and the scene is 3 million+ polys, im running out of ram all the time.. (even with 3gb switch on 2gb machines..) getting to 1.8 / 1.9 gig then "unhandled exception"

ive tried every memory use reducing trick i can think of, but this "use irr. map." technique, means i dont have to calculate or manipulate the irr. map in any way, and it actually appears to render faster and use less ram (from very first test..) than any other way iver tried...

[super gnu]

i have considered comping the people in afterwards, and have done exactly that in the exerior sections of anim. but this is an interior office scene with loads of furniture and very "patchy" lighting... comping becomes tricky, and using a fixed irr. map doesnt work very well, because the people move through areas with quite different lighting...

im not after the "perfect" gi solution (ie. calculated every frame for all objects) but a halfway technique which gives me some bounce lighting on the people to augment the direct lights.