Is there an Option or UI for filtering the Scene Graph Tree? It would be great if we could have filters for what's shown, kind of like how the Geometry Spreadsheet does (at the very least, be able to filter prims by name with regexp).

If it isn't there by default, I can't remember, is the Scene Graph Tree extensible?

There is a filter field at the bottom that lets you filter by a pattern. I think it only matches prim names though.

Oh yup, I see it - it was collapsed. Want to keep the second part of my question open though - I know some of the new interfaces in Houdini are extensible, but not sure if SGT is.

No, it is not extensible, other than being able to add context menu items. Most of our new panels are extensible by virtue of the fact that they are written in python, and so you have all the code and can modify it. The SGT pane is too performance-critical to be done in python, and making C++ UI extensible is a whole lot more work. Allowing the addition of custom columns is one thought we've had that could be simple enough to let us create some sort of plugin architecture. But that wouldn't have helped for your request (if the feature didn't exist already).

Thanks @mtucker, that makes sense.