I took a random Megascans mesh (rock_assembly_tazj1) to compare disk size of FBXs. LOD0 is 706 kb at 16302 tris, while the Highpoly source is 115 mb at 1.999 million tris. That is 162 times bigger size on disk.
just how good can they come up with better compression and optimizations? is the new Zen loader really 100+ times faster?
Think of the other implications, everything needs to be 100+ times faster. You still need to save the mesh file to disk from within the editor. There’s mesh destruction/slicing systems (good luck keeping those in memory). There’s vertex painting tools. There’s new in-engine mesh modelling/editing tools. There’s Niagara mesh sampling on CPU. There’s particle meshes. There’s per-poly collision option. There’s shader effects (snow buildup, footsteps and trails, etc).
And also think outside Unreal. Most other 3D softwares can’t reasonably handle opening/saving/viewporting million-triangle meshes. There’s Source Control upload/download speed. There’s Source Control bandwidth and disk usage.
I think it’s fair to be prudent about replacing the existing tech with Nanite when the rest of the supporting tech isn’t built for what it implies
In general I’m not a fan of getting the choice removed. multipurpose engines like Unreal should be about choices. Nanite for such usage seems to rely on fast SSDs (we know is it was showcased on PS5 which is ~8GB/s), but is the adoption on other platforms there yet?
for a Megascans-UE4 workflow this means relying on the highpoly mesh entirely (very questionable), or having control by manually subdividing+displacing the lowpoly mesh with the displacement map and re-exporting (pretty horrible workflow IMO)
what about Landscapes? people please don’t just say “make a mesh to use with Nanite” - just think it through. I’ll assume the solution for Landscapes will be the new virtual heightfield, but is that enough for closeup detail?
for Water rendering I guess this means relying on actual dense meshes. not terrible but still seems wasteful. unless the new water plane rendering can be used outside of their water system
what about Skeletal Meshes (unsupported by Nanite) ? in practice I don’t know how often Tessellation is used for characters but they seem like a really good match.
and for shader effects that make use of displacement now we’ll have to do all of them in WPO, meaning we will forcefully need a dense enough base mesh to achieve anything.
I can see where this is coming from - Tessellation was never efficient in UE4 and it probably conflicts with nanite. However other engines can handle it (Frostbite, Gears5 UE4 branch) so I always hoped UE4 would eventually catch up 