[Sidefx-houdini-list] calculating du dv in sops

[Rangi Sutton]

Andrew D Lyons wrote:
> Hi,
>
> Has anyone got a trick for calculating du dv at sop level?
>
> We have a surface with good uv's and we want to derive point vectors
> that orient along u and v.
>   
Hey Andrew,

I've setup a system where we baked out P to maps, then used cops to 
calculate the surface derivatives. Should also work with uvs. There's a 
derivative vop that wraps up easily into a cop node.

Someone might have a better idea that doesn't involve baking though... 
I'd be keen to hear it!

Cheers,
r.