Lightmapping: Progressive Mode (PPT, QMC)

Hi,

I’m wondering if it would be possible to implement a progressive qmc mode in the lightmapper?
Here’s a quick video that shows what I mean: https://www.youtube.com/watch?v=TJM5DeJfaYA

Of course it would be slower than the current photon mapping but it would also be far more accurate. Moreover you could cancel the baking progress whenever you want and store the current progress in your lightmaps.
It would also work via distributed network rendering as it’s brute force.

So would this be possible?

Best regards,
Daniel

That’s usually very slow to do on the CPU, and while you could use the GPU you would be limited by the amount of GPU memory (not good for game worlds) also, that doesn’t cover the entire map, only what you see so it wouldn’t be super useful for lightmapping.

Here’s a little update on this topic. The Unity guys are working on such a feature:

Not bad, I could see how this would be useful. It’s not quite as versatile as a fully dynamic realtime GI preview would be, but it could be good enough in the meanwhile for anyone using lightmaps in a project.

The only question on my mind is, how does it handle a more complex scene? The test level they used it in was very sparsely populated, and not a very good representation of a complete level in a game. It’ll be interesting to see how the feature works out once it’s in the hands of some Unity devs so we can get their impressions on it, to see if it would be worth asking Epic to look into.

It’s useful for seeing a preview of the lighting, but they said in the blog post it’s about the same speed as Enlighten when building an entire scene. Which, Enlighten is not very fast.

Looks pretty cool, per object lightmap baking would be handy though.

Could see this being handy for previewing changes without have to wait for entire level.