What is the best way to subdivide a polygon surface to get it smoother but leave the UV's alone?

You could try an attribute copy or attribute transfer from the original source. Place it after your subdivide node.

So out of the myriad subd options in the poly subdive sop there is no way to not affect the original uv vertex positions?

By subdividing you've inherently changed the geometry and so no longer have the same uv layout;

There is no longer an ‘original’ geometry.

BabaJ
By subdividing you've inherently changed the geometry and so no longer have the same uv layout;

There is no longer an ‘original’ geometry.

The UV layout should be the same, just subdivided. Point order will change, of course, but that's another matter.

In maya there is a way to set it so the division leaves the uv's intact and inserts the divisions between the original points…

The UV layout should be the same, just subdivided. Point order will change, of course, but that's another matter.

But ‘UV layout’ is an abstraction…so in a way it does stay the same. What does change is what the ‘UV Layout’ is referring too.

So if the geometry changes, one has to change the reference to the ‘UV Layout’ in order to keep the original.

Wren
In maya there is a way to set it so the division leaves the uv's intact and inserts the divisions between the original points…

Well you could do what Enivob suggested or even wrangle…and then if you don't like seeing it as it is…just wrap it up as an asset so it gives you the appearance of working the same way as in Maya

On the Subdivide SOP, there is an option near the bottom of the parameters called ‘Vertex Attributes’. Assuming your UV's are vertex attributes, you can set how the values are interpreted after subdivision in this menu.

The method you're looking for is probably ‘linear everywhere’ which simply adds the subdivision without affecting the UV attributes at all. Potentially, you may instead want ‘Sharpen Boundaries’ which will leave the boundaries alone but allow some deformation of the interior UV values.

Cheers,
Scott

Ok thank you! I'll give it a shot.