As a Roblox developer, it is currently impossible to use SolidsModels/UnionOperations as their MeshPart counterparts to have their Internal AssetIds being rendered inside a SpecialMesh
Reason for this request is since you are not allowed to insert MeshParts or Unions in RunTime then you’ll most likely use a SpecialMesh.
local oSize:Vector3 = MeshPart.MeshSize
local size:Vector3 = MeshPart.Size
SpecialMesh.Scale = Vector3.new(size.X / oSize.X, size.Y / oSize.Y, size.Z / oSize.Z)
Unions have almost the exact same internal properties and everything with the only caveat that they cannot be rendered in a SpecialMesh.
And yes, I know there is a way you can convert the union into a mesh by exporting it as an a .obj then import it as a 3D mesh which turns into a MeshPart. tho why go through this hassle
My use-case is a custom map importer that parses RBXMs. Being able to render a union in runtime would be nice.