>>2885054>> can it be chained properly?Yes, but maybe it depends on what you're imagining and may work differently in different software.
>>2885059Not truly arbitrary in our context. You can store float4 values in the 0–1 range (if using the weight/UV mapping (painter) tool) or unlimited float4 values (if you write them down in those fields manually) in 4 additional UV slots per vertex, and if you're fully unhinged, you can even go for the 9 SDEF fields (float4 position and two float3 with seemingly unlimited range) and float2 for the regular UV texture & EdgeWeight float (both unlimited) if it's not an actual visible model. That's the limit of extra vertex data that can be passed to HLSL from PMXE, but I'm not sure how much of it is provided by MikuMikuDance (can't find a single instance of SDEF or EDGEWEIGHT values provided to VertexShader in MME-oriented effects; additional UVs, a.k.a. TEXCOORD1–4, definitely get used). You can write tangents or whatever that can be expressed as floating-point numbers to those additional fields, but the model has to be prepared for it on a vertex-by-vertex basis, unless you make a C# script to batch copy the values from a easily editable property or use Blender and figure out how to write the data you want using UV mapping. Also mind that it can break effects which treat additional UVs normally.
