saving LC in IRMap

[Da_elf]

I seem to remember hearing somewhere that when using LC/IR that has been saved you can use just the loaded irradiance map since the LC pass is saved in that pass. is this correct?

[LarsSonparsson]

Yes, that's correct.
But if you want to use lc for glossy rays, you still have to keep it on.

[svetlozar.draganov]

In general if Irradinace Map is used as a First Bounce Engine it stores the information about the Secondary Bounce Engine - which means that it also saves information about Brute Force.
I've never tested it with PhotonMap - but I won't be surprised if it saves it too.

[3LP]

Oh, I didn't knew it would save the BF secondary as well!
Is that a good idea anyway, I mean, isn't the IR down scaling and interpolating information to have smooth results?
But the whole point of going BF would be to have sharp information, even if that means noise... which means that it would be a bit strange to cache the BF...

Interesting anyway, thanks for the tip

Stan

[svetlozar.draganov]

Irradiance Map will smooth the information from Brute Force even when it is not loaded from file. All the visible pixels in the final render are calculated via Irradiance Map since it is first bounce engine.
Secondary bounce engine calculates GI in areas not visible by camera-rays and its information is forwarded to the First Bounce engine when it is required. Since Irradiance Map is adaptive approach and it uses Brute Force as input information the final result will be always filtered by Irradiance Map.
I've run a few tests here with a hair and fur scene with a lot of tiny details and I haven't got any difference between IM loaded from disk with baked BF (secondary bounce OFF), and IM + BF normal approach - both renderings are exactly the same.

[3LP]

Yeah sure, I wouldn't think that you would have any difference from loading a file or doing it straight in the render, my main concern was of using the IR filtering for secondary ray that has been BF.
When you expect to use BF because it's clean and tidy (and use a lot of computing power for that matter), it's not to have a IR on top that is actually filtering/smoothing/flattening everything afterwards.
But I guess that's why we love RT and going dual BF so much

Thanks for the info anyway, I will keep this in mind!

Stan

[super gnu]

i dont think the irradiance map "stores" the LC / secondary bounces as such...

if i understand correctly the irradance map/primary uses the secondary bounces in its calculation, but secondary bounces are never directly visualised in the render. therefore for rendering you can disable the secondary bounces after the primary have been calculated. unless, as Lasse says, you want to use the LC for glossy rays.

obviously if you are using BF for primary this is not possible as the primaries are never actually precalculated.

[svetlozar.draganov]

That's correct.

Secondary bounce information is always used as input information for the First Bounce engine - and if IM is used as First Bounce it saves All secondary information in itself.
Since Brute Force doesn't have option to save - it is not possible to save any information inside it.