I'd like the user to be able to create, manipulate a curve INSIDE of a locked digital asset.

I'm noticing a curve handle which I've tried connecting to the "coords" parm at interface level with no luck, also a method describe in a tutorial to have a state to sidefx_attribpaint with import block, perhaps it's similar to that approach with sidefx_curve? (not recognized) or just "curve" which does seem to work but still no results.

I don't want the user to make a curve and import it, this should be inside of the digital asset. Import Block, Handles, Editable Node, all good. I just don't want diving or imports.

Or, is there any information on how the handle/curve works in an hda? It doesn't seem to exist in the help.

Thanks!

It would be helpful if this wasn't an original solution. This remakes a curve paradigm as opposed to simply using a curve sop and working with it at a different hda level. Looks really cool, but not what I'm after.

Basically I see all these interesting HDA handles, and mysterious and undocumented sidefx_"states" however, I don't see any documentation on any of it. Am I looking in the wrong place? It just seems like if they're in there there should be some functionality to them.

The xform handles work fine, but what are the curve handles and how does one set them up?

If it's not possible to actually have a curve drawing handle or state with an hda so be it. But there should be a clear answer. SESI? Help?

I pretty much want to reproduce the spline drawing behavior of a spline in an unreal/unity engine asset within Houdini itself. Simply have a curve that fills out the little position information with user interaction as opposed to making, connecting, disconnecting curves. I have all the other components of my tool working properly, just need this piece.

Could it be a good case of writing to support for this one, Andrew? Maybe the curve node is locked due to the old type of the curve node, just guessing? Still didn't use the python states on that one...
Good luck, I am also curious of how this will play out.

Messaged, hopefully will figure it out

Heard back from support. It's great that they were able to figure it out even if the answer wasn't one I wanted.

curve creation is accomplished with a custom curve state. Unfortunately, the state requires the SOP to be a Curve SOP (it will not work with an HDA). It also uses a "Curve Points Options" handle for editing the points.

You can use KineFx Skeleton SOP as a workaround. kinefx__skeleton state is based on python states API so it can be promoted to the hda level.

This one depends on your use-case. It won't be the best ux for the task probably as you'll have all the overhead of the skeleton sop state. But that could work, it's perfectly capable of creating and manipulating polylines.

I've attached a simple example.

Have you considered promoting an Add node to top level of your HDA and converting it to a poly/NURBS curve?