light cache resolution question.

[stezza]

If the light cache was calculated at say 640x480 but the the final rendering was 1280x960. Would using the lower res maps for higher res image give predictable result?

Thanks

[Svetlozar Draganov]

Light Cache is resolution independent - once calculated you can use it in every resolution.
Here are two identical images with size 1000x563 - on the first one LC is precalculated on 10x6 resolution and the final render is 1000x563 - on the second LC is calculated with the same 1000x563 resolution.

[stezza]

Many thanks for the information Svetlozar I never knew that, thats going to save me plenty of time!! If only I realized this a few years ago...

Cheers

[bigbossfr]

Light Cache is resolution independent - once calculated you can use it in every resolution.
Here are two identical images with size 1000x563 - on the first one LC is precalculated on 10x6 resolution and the final render is 1000x563 - on the second LC is calculated with the same 1000x563 resolution.
[ATTACH=CONFIG]13570[/ATTACH][ATTACH=CONFIG]13571[/ATTACH]

So we can bake the LC with a little resolution (10x6) and re-use the map for the final resolution.
But, the question is : bake the LC with a little resolution will be more faster than bake the LC on a final resolution ? or we do not have benefice to do this ?

[Svetlozar Draganov]

There is no differences in the render-time between LC calculated on different resolutions , otherwise it won't be resolution independent
According to my tests there is a very very small difference when using different resolution - it is not noticeable in the render but it is there.

10x6 resolution = 269kb LC map
1000x563 = 269kb LC
10000x5630 = 281kb

The fired rays between the second and the third are also slightly different - but I haven't found any differences in the final render.

[stezza]

OK thanks for that I naturally assumed it would be much quicker to calculate smaller maps, but as you say that's not the case, I don't feel so daft after all!

[Svetlozar Draganov]

Yes this is normal because everything works much faster on smaller resolutions - but it is because almost everything is resolution dependent, which is not the case with LC.
It would be fantastic if there is a way to calculate everything on low-res and then just do a final render on high-res with the same quality - but unfortunately there is no such thing as free lunch.
We have to pay either with the quality or with the render-time.