It was a new feature added to DX8.1 that did not make it completely into the VB implementation. I don't think we can get to it very easy using VB since it was left out of the type library.
Microsoft Visual Basic DirectX MVP
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Does anyone know why this appears to be missing? It's in the docs as a macro to set up the tangency Quats for a Squading operation, but it's coming up undefined. Any help appreciated.