vray GI : world VS screen scale + interpolation sample

[bullfrog]

Hi everyone.

First thread on the forum for me.
2 Questions are bothering me with Vray:


- light cache & scale value.

I do understand how the world scale works and why the rays appear bigger as they are far away from the camera.
But what I do not understand is the screen scale because I can read that this metod tends to unirformize the rays throughout the image but at the same time the rays appear smaller as they are close to the camera.
Why are they?


- When I use the light cache in addition with the Irradiance, I have the feeling that the interpolation samples of the light cache are useless but only the interpolations of the irradiance work.
Is that correct?


Could you enlighten me for a bit?

Thanks

[bullfrog]

I did some tests concerning the second question.

It seems that changing the interpolation samples of the light cache does change nothing only if the irradiance is "loaded from file".

Strange...

[vlado]

Why are they?

Because of perspective.

- When I use the light cache in addition with the Irradiance, I have the feeling that the interpolation samples of the light cache are useless but only the interpolations of the irradiance work. Is that correct?

You are correct, yes.

Best regards,
Vlado

[bullfrog]

Actually I did some more test. The interpolations of the light cache seem working with the irradiance only if you don't save the irradaiance in a file.

[Svetlozar Draganov]

Interpolation of the Light Cache are saved into Irradiance Map and if you load Irradiance Map from file Light Cache Interpolation are ignored since they are already saved into IM.
However these interpolations are not saved into Light Cache, so you could still control them if you load LC from file.

[bullfrog]

Make sense. Thanks svetlozar_draganov.

I guess it's why the reset button exists in the irradiance rollout.