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Any way to isolate Volumetric Lightmap Samples?

Hello everybody!

I’ve been experimenting with Volumetric Lightmap (:rolleyes: yet again) and still was a little upset about the problem of the light bleeding onto the character when you approach the wall from the inside of the interior. So I left the default grid settings and decided to figure out the appropriate wall thickness to counter that issue. Turned out that for 100% accurate result walls need to be 3 meters wide!
Of course, you can go less than that considering that it’s unnecessary to crawls alongside the walls all the time, but still. Regular 30-50 cm is way too small for my taste :slight_smile:

So I asked myself: is there a way to manually restrict sample interpolation inside a given area?
So far I don’t know the answer to that question, therefore I’m asking you guys!

I wish there was a volume that will use only those lighting samples that are enclosed inside it. That way it would be a nice and easy fix for this issue. Maybe someone knows something useful regarding this?

There is, it’s the Volumetric Lightmap Density Volume, ostensibly it will allow you to set a fixed density or a limited range for the engine to use.

In practice I find it doesn’t actually work half the time.

Exactly! And it not quite for this purpose either.
Those samples are usually relatively far apart. From a user point of view, I don’t see a problem to place the Volume that will simply exclude all the samples that are outside of it for the dynamic lighting calculations on movable objects that are inside that Volume.
It would still be better to use the nearest sample that was calculated inside the Volume even if there are non at the edge, instead of looking for those that are outside. And perhaps provide that Volume with a radius for manual tweaking, if some of the samples inside received the lighting form the outside.

Fair enough, but the samples are (supposed to be) based on whatever density you’ve set in lightmass, if the volume actually worked consistently then you could increase the sample density and then use the volumes hierarchically to allocate density where needed to avoid light bleed. while still keeping memory usage within reason.

I don’t know if what you’re suggesting is feasible to implement, personally at this point I would settle for just having any degree of manual control over sample placement.