I am trying to determine the performance budget for our Nanite assets. While I understand Nanite handles high-poly geometry efficiently, I want to avoid “overkill” that might waste disk space or cause overdraw issues. Our building model has 3800w tris and it occupies a large amount of video memory: 300+Mb. However, I used another model with the same number of faces, which only occupied less than 100Mb
Hey there! I generally don’t recommend putting a whole building as a single Nanite static mesh. Instead, you’d want to break up the building into smaller, modular pieces that you can then instance to create a whole building. CitySample has an example of this, albeit before the PCG framework was available.
Nanite will also stream the clusters it needs in and out of memory, and its default budget is 512mb (r.Nanite.Streaming.StreamingPoolSize). The only way an entire static mesh’s worth of clusters would be loaded is if all of them are equally and perfectly visible, which is unlikely. The GPU memory values shown in the static mesh editor HUD are showing you the low and high water marks, with the compressed disk size representing the amount of space it’ll occupy in the installed package, but not necessarily its full memory overhead.
As far as guidance of vertex or triangle budgets, I like to think of it the way I think of textures. Most of the time I don’t need an 8k texture to represent something in my environment, and similar I don’t always need a 2 million triangle rock. It’s all about how much detail you can see.
If you want, you can also tune the number of triangles that Nanite generates based on your input mesh by changing either the Keep Triangle PErcent, or Trim Relative Error values in its Nanite settings. That may help!
Thank you for your reply. We will try it!