With both Unity and Frostbite working on their respective implementation of a GPU accelerated lightmapper, I hope that Epic also considers adding such a feature to UE4. Given how long we’ve been stuck with the painfully slow lightmass, an interactive lightmapper would be a godsend! It can’t be overstated how much of a game changer this would be for every single lighting and environment artist working with the engine. Just imagine having instant visual feedback rather than waiting for minutes or hours!
I wouldn’t necessarily say that, but I think Epic is trying to just skip a lot of the the static hassles and go straight for a more realtime GI approach with the DXR stuff.
It would be pretty awesome to have a progressive lightmapper though. Much like when using realtime rendering previews with iray viewports, where the scene starts out super pixelated and then comes into focus, it makes sense that you can apply a similar progressive approach to lightmapping and due to many people being already used to features like that, in other programs, it should definitely be implemented into UE4.
Personally, I’d like some kind of progressive lightmapper, while in viewport, to give me a rough estimation of what the scene will look like. When I’m mostly happy with it, I’d then bake it properly. Much like what you do in a lot of 3d packages that use things like iray for viewports.
Lastly, if it’s on the GPU, it will likely have some limitations. In programs like Maya/3ds max, there is a lot war between different rendering engines that are cpu or gpu based and there are a lot of pros/cons to each approach. CPU will yield the most accurate results, while GPU will usually yield faster, less accurate results. While I haven’t looked too deeply into it, I’m pretty sure this is one of the main reasons why Microsoft is working on DXR so that they can overcome some of those limitations.
