Hey,

Little confused over vellums handling of a hairs frame for matching pre / post simulation and just wanted to clarify for sanity!

As an excercise i have Rest hairs and Sim hairs i want to match some sort of orient / matrix on:

1. To start the Groom is guide deformed and creating Orient - which appears to be per hair
Normal, Tangent and Bitangents made with polyframe
These are run for both the rest and simulation hairs

2. Passing the sim hairs through Vellum Hair Constraints the orient changes to per point, regardless of having compute missing orientation on or off

3. Coming out of the sim the polyframe attributes dont appear to update. Recreating polyframe after results in some dodgy spinning, but orient is doing exactly as it should. Though it no longer matches the rest hairs.

I know vellums clever with this stuff internally, so what should i be doing to see vectors / matrices come through accordingly deformed? or would i need to run the rest hairs through a vellum hair constraint node to match up and rely on the vellum orientation attribute?