I'm trying to control this with a generic 3D controller based on real arm bones.
Here are the actual bones. And I created the joints here based on the actual bone names.


This is the "Base.skel".


And I created a separate joint for Guide.



Now I want to merge this with the previous bone(Base.skel) and send it to the autorig component.

In this process, I want the elbow guide joint to control the ulna and radius as if they were real bones moving.
I want to use parent constraints and aim constraints like I did in Maya, so should I set up the joints in Base.skel with rig attribute VOP before putting it into the pack folder as shown below?
(I tried to set up with rig attribute VOP but if failed, I think I need to study this a bit more.)


Is there any way to connect this from the autorig component side, especially with the APEX SCRIPT that came out in 20.5?
I'm looking for advice if there is a good way to go about this solution.

For now, I'll upload the file that failed as a sample. (I was working with an indie version of Houdini 20.5.)

I don't think you understand what APEX does. It's not your fault: APEX is a quite new thing. Let me explain:

First of all, APEX doesn't "understand" Parent Constraint VOP. Or any constraint you set in KineFX. At all. In APEX workflow, rigging happens in APEX. If you use Parent Constraint VOP, rigging happens in VEX, in other words, at SOP level. APEX will only run what's in the APEX graph, not your whole SOP graph, so it doesn't even know that Parent Constraint VOP exists.

I suppose you're trying to make ulna and radius follow the elbow bone. You could use APEX Script for this, but there is an autorig component to make simple parent constraint. It's "transformdriver". See the attached file for a simple example.

I really didn't know anything about APEX, and now I understand it a little bit better. Thank you, and I really appreciate the examples.

There are some new nodes within apex that allow your set up your parenting and create extra controls within a component script, but I’d suggest that - until there’s better docs explaining how to set this up - you do all your parenting within your guide skeleton.

While APEX doesn’t register constraints set up in kinefx, it does respect any parenting you establish, so there’s a lot you can do before you set up any constraints within apex.