dan.goyette (10/6/2023)[hrI created a new CC4 project, and added the default CC4 "Kevin" model, and exported the character (With Subdivided mesh enabled). The resulting FBX file is about 33 MB in size.
Are you sure about that? Subdividing only the hair to 1 level results in a 84MB Fbx file for me. 180MB+ for 2 subdivisions.
The FBX format may have ways to compress the data, but the raw mesh data in Unity doesn't. Each subdivision level effectively quadruples the number of verts, each blend shape is effectively a duplication of the entire mesh (I don't know if Unity does anything to reduce that in the raw data, but I know it's stored more efficiently in the GPU). On top of that, Unity's mesh data can only store vertex data in blocks of 32k verts, so what your seeing might be those blocks, not the blend shapes (or not just the blend shapes)
It's not just the positional data either. Each raw vertex is position, normal, tangent, vertex color, skin weights (multiple), uv coordinates (multiple). That's a lot of data to be quadrupling with every subdivision level.
Also Kevin's hair does have an awful lot of blend shapes: 203? So I'm not surprised when subdivided it extracts to be so large.
That said maybe removing empty blend shapes during the extraction process would help. I would think most of those 203 blend shapes are empty.
Long story short, subdivided meshes are
enormous, be very careful with them in Unity, you'll run out of memory fast.