Thoughts on Nanite and Lumen

A stock photo image of hanging lights, faded and blurred behind a title saying ‘Thoughts on Nanite and Lumen’ with an underline of ‘I have a lot of these things’

One of my recent videos was on photorealism within UE5, where I mentioned various things about Lumen, Nanite, and UE5’s potential. But due to the unscripted format, that also involved showing things off, as well as answering a specific question, not all of my opinions were revealed! Until now.

So, first off what are Lumen and Nanite? Lumen is essentially a new system of lighting, that through the use of mathametical equations I could never do, does a far better job of reflecting light than previous realtime engines. Raytracing isn’t even required to use lumen, however if you do have a graphics card with raytracing enabled, I highly recommend enabling hardware based lighting. For those of us still scrounging for the mythical 3060ti, the devs at Epic figured out how to get lumen working without raytracing.

            And it’s more than not needing to build your lighting every time you move a static light. Lumen does something amazing, where it reflects the colors of surrounding objects. (This is where those complex math equations come in.) It’s a seemingly small detail, but lighting art is comprised of seemingly small details. It can even reflect the colors of moving characters, adding another level of realism.

            As for nanite, I made a twitter thread on this actually. It’s a fairly old concept, but being introduced on a larger scale, with new technology. A 3D model imported as nanite, has its tris organized into groups. Nanite then decides what groups to show based on where the camera is. It’s like combining LoDs with what zBrush does when you’re working on that million polygon sculpt.

            So what can be done with lumen and nanite? What’s the potential? As I mentioned in the video, I do still believe these are mainly for movie and show production. More studios are beginning to integrate Unreal into their VFX pipeline, which means Unreal needs to make their lighting even more realistic. Additional, the VFX pipeline for a movie, which has access to render farms, involves higher polygon models than games have generally required. Both Lumen and Nanite present additional appeal for VFX studios and productions deciding the best course.

            Yet there is still some use for games, even without massive changes to the 3D modeling pipeline. For example, when you import a model as nanite, it is able to create multiple static meshes based on different LODs. This is intended so you that if you release a game for a console or pc that cannot handle nanite, there can be a nanite-free build while still including the same models. However, this also looks to me like an easy method of creating LODs on the fly, speeding up a part of the process.

            In addition, poly counts for opaque static meshes are able to be higher without effecting hard drive space. That, on top of how nanite handles rendering, means artists can spend less time optimizing, and more time on other assets, or making assets better quality.

            As for lumen? Well this is where things get interesting. Lumen is reportedly able to be used with Niagara, and can also interact with objects. From the trailer for UE5 alone, it seems like there’s also sorts of opportunities for light based and sound based mechanics. What does that mean for rhythm games? For narrative games? Who knows, but I see some opportunities there. In addition, while the new lighting system is intended to be used for realistic environments, I’m excited to see what becomes of more stylized environments, now that there’s more color reflections, as well as better support for emissive textures.

            So in short, I do believe these features were more intended for the film production users, as well as CAD users, but there are uses for game devs, especially devs who think outside the box!

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