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Nanite Workflow Question - Decimated & Projected Subdivision of UV'd Autopo for Gameres


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Hello! For static environment objects that require "simple" uv patches to maximise texel density I have found that the best workflow is one similar to the way Maria Panfilova does her textured sculpts for presentation. In this case, the workflow is
- Make sculpt
- ZRemesh & project to get semi reasonable loops
- UV Remeshed low
- Pose 
- Decimate posed mesh with UV preservation on
- Take into texturing app for texturing, render

This matches very closely to the workflow developed by the Coalition for creating environment props for Nanite in some of their recent tech demos, and is generally a great method for producing decimated meshes that preserve the simplicity of uv shells and also makes unfolding much faster, since you're working with way fewer polygons. Coalition did a lot of proxy mesh projection to bring simple UVs over to their nanite lod0. I will demonstrate briefly:



So far 3DC decimates, supports autopo + uv, etc, but I am a bit stuck at the subdivide / project / decimate with uv preservation step.

Does 3DC support this kind of workflow, and if it does, what am I missing?

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When you Remesh to a lower poly quad mesh, you don't need to decimate anymore. You can Bake the details down to the lower poly mesh, in the Retopo Room (via BAKE menu) > export it directly from the Paint Workspace afterwards. When you go through the BAKE menu, choose MV (Microvertex) because it will let you export with the displacement baked into the mesh on export. To do this, your baked copy of this lower poly quad mesh will be in the Paint Room. From there, go to the FILE menu > EXPORT > EXPORT HIGH/MID POLY MESH  

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You can also test the new export option: Simplified export

File > Export > Decimate, automap export:

Sculpt objects may be exported as low poly + texture using the special script that automates this job: it decimates, bakes, and exports the object + textures. File→Export→Decimate, auto-map, export.


Auto-export improved essentially:


  1. possibility to export assets directly to Blender with PBR.
  2. centering assets if need.
  3. export multiple assets.
  4. optional possibility to export each asset to own folder.
  5. better compatibility with UE5 (but still not perfect because FBX does not support full PBR).
  6. possibility to set custom scan depth. As result, auto-export becomes really good and convenient assets creation tool.


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Hi there! The export displaced high is super cool and I didn't know it exists, but a couple things:

- Blender does not support "preserve UV borders" in its decimation algorithm, which means I can't export the high into blender to decimate the high.



The zigzag uv borders might be tolerable but make me a bit sad! To be honest it seems "mostly OK" except when I decimate too much it gets a bit sketchy. This workflow might be usable as long as the decimation is subtle, but I will have to watch out for torn / warped UV borders.


Unfortunately I don't really consider auto UV to be super usable for games, since for games anyway texture size is limited and each island incurs a debt to wasted uv space. Autouv on decimated models results in "shattered" uvs with tons of islands, and this winds up performing very poorly in terms of coverage. Here is the results of "decimate, automap, export"


For games anyway, fewer islands with a bit more stretching is preferable to more islands and less stretching. Esp. since most texture data in engines for detail maps / tileables must also be carried on the UV. So I consider that option off the table for production, at least for now, sorry!

One thing I did hit upon is that using point-to-point mode makes UVmapping decimated models not that horrible? And as long as its around 500k or less tris it seems to be reasonably interactive when unfolding. And it shouldbe possible to transfer uvs from a lower poly to a higher poly decimation, should I need to bring the mesh down to like 100k and then use transfer attributes modifier to copy the uvs over to a higher rez mesh. IMO this is still less optimal than the zbrush method but it does work and means I don't need to hop between apps which might be enough to win me over since I'm primarily using Coat for environment sculpts


Edited by wendallhitherd
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Just discovered a pretty good workflow that seems like the best of both worlds and preserves uv edges about as well as can be done. It has the advantage of autopo's simple topology and decimation's accurate shape preservation: 

Use an autopo mesh for the UV proxy source, this is sort of like a cage:


Send this to Blender. Also, send out a decimated sculpt to Blender. The decimated sculpt can be arbitrarily highres, up to millions of polygons.

In Blender, use the transfer attributes modifier to project the UVs and seams from the proxy autopo to the decimated sculpt. 



After transfer to decimated: not perfect, but close enough? Will have to try taking it through baking stage and seeing if there are any serious issues

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