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lightmass

I was just wondering if lightmass could be moved from CPU to GPU for faster execution times. I’ve noticed the client itself doesn’t appear to have changed much since UDK. The interface actually looks identical to UDK.

I do use swarmAgent for networking, but I suspect that it would still be faster to go through the GPU. Also in the mean time I tried to find a way to install it as a service, but didn’t have a lot of luck.

Hi -

I have put in a feature request to allow Swarm Agent to use the GPU for computation of lighting builds, for reference UE-13037.

Thank You -

GPU rendering would be very limited, since you have to load the entire map and most people don’t have much GPU memory.

Please stop posting the same line in all sites.
Yes we know that.

This is a thread unrelated to you, if you already know the information then ignore it

Hey its been a fair while on this 1 and I haven’t seen anything around on the Trello board. Any chance of getting an update on if this is going to be investigated at all?

Hi ZoltanJr,

This is still backlogged and I honestly wouldn’t expect to see something like this implemented anytime soon.

While it wouldn’t be impossible to use Lightmass calculations with the GPU, but this is not currently being worked on or planned in the near future. The ideal solution is a lighting algorithm which renders real-time using the GPU when you are previewing, but then can be baked down into a lightmap using that same algorithm when you are a ready build. However, there are some challenges with this though. It would be hard to make the editor scale down, all of the current GI methods would have to be re-written, it would not be able to get as high of quality of end results, and it could make the editor much less stable due to the load put on GPUs. GPU’s are known to be notoriously unstable with heavy loads.

Hey, is it possible to get an update on this feature request?

This is something we would NEED anyway… with a option to switch between CPU and GPU… I have 2x1070 and 2x1080ti, also NvidaXp … computers… I definitely need it, because I am calculating light builds for 5 hours on i7-4960X cpu… so its a must

I’m with Patrik, build times are insane for indie developers that cannot have a build farm or many PCs, I think GPU Lightmass should be considered in the short term, it would be very useful Epic pls

It’s still limited use due to memory, if you’re struggling with long build times then chances are that you have more content than you could fit into GPU memory.

I really dont want to be rude here, but man…it doesnt matter! I get your point, but it doesnt add anything to the discussion at all! There are people that would heavily benefit from such a setup and others just wouldnt. Thats it. No need to constantly point out that YOU think its not necessary.

If I have a crazy archviz scene then its just gonna take a while. And if that while could be less…then that would help. “You have too much content” doesnt help at all :wink:

There are a lot of smaller studios that do archviz with just one or two guys and they dont have 20 PC as a build farm, but they might have a very strong graphics card?
I would love to see some improvements here since I am constantly struggling with long baking times because of quality settings and not necessarily because I have a lot of content.

My 2 cents! Cheers :smiley:

My point is that the usefulness of GPU rendering for lightmass is probably not that much, few would be able to take advantage of it so a lot of people asking for it would be disappointed to find that many of their scenes can’t use the GPU. For baking lighting in a game it uses a lot more memory than it does for something like Vray.
If they want to do some lighting development they should put it into a dynamic GI solution. In fact, if they brought back SVOGI for the people that want to do renderings that would be much more useful since you woudn’t have to build lighting at all.

I don’t know. The GPU accelerated lightmapper for Unity looks quite promising actually.

Most people’s scenes are going to use a lot more memory than what they have there. The big issue with games is that it has to store the lightmaps on top of everything else.

And THIS is exactly why it’s so powerful and useful :slight_smile:

Your not jumping ship on us are you?

Yes, I think the core algorithm of UE4 lightmass needs to be entirely replaced. Photon mapping must be abandoned. It’s a fairly obsolete GI solver which usually delivers weird light leak, incorrect illumination distribution and eats massive memory. Then use pure path tracing based solution instead, like Unity’s new GPU baking feature.