The following is a short and simple setup for how to bring objects from world space, to uv space, back to world space:

KK_UV_to_World.hip

There are many reasons why you may want an object flattened into its UV space. For example, if you wanted to wrap an object in a complex geometry, such as a knit, it would be easiest to flatten that object first, place the knit geo where the flat pieces are, and then transform that knit geo back to the original mesh based on its UVs.

One prerequisite for this setup is that the incoming object needs relatively clean UVs. You can get away with quite a bit by using uvunwrap and uvlayout SOPs, but it is best to have proper sculpted UVs.

To flatten an object to its UV space:

1. Split incoming UVs with a “split UV seams” SOP (the flattened UVs will not look correct unless you split the UV seams)
2. Promote the UVs from vertex to point attrib via a attribpromote SOP
3. Set position to the UV point attribute in a wrangle:

v@P = set(@uv.x, 0, @uv.y);

1. Do whatever you want to the UV space object
2. Bring back the UV space object to world space via the “uvsample” function: (the worldspace object is input 1 on the wrangle)