I am learning the new Apex system and loving it but am struggling with creating an IK system for this mesh.

While I know how to do the basic IK system, I have not yet found/understood how to create an IK system with more joints and one that limits the rotation axis in the top two.

Does anyone know a way or has a suggestion on how this can be done with Apex?

There is FBIK node. However rotation limit isn't supported yet. So nope. APEX is in beta, please lower your expectation.

Why would you need more than 3 joints for the main-arm (which is the default ik-setup anyway) + using a fk-rotation for the manipulator? You could limit the rotations using clamp-nodes.

I mean you can do that, but >3 bone IK is the "standard" way to rig this kind of mechanical arm.

Or you can use KineFX, which has better FBIK support with rotation limits etc.

Or you can write your own FBIK in APEX. People are going to tell you APEX is a super flexible system where anything is possible. (plebs who are not able or willing to do this are simply not good enough for Houdini )

No worries, it's on the TODO list.

I build a digitigrade IK leg yesterday (posted it on the discord server).
perhaps you can take a look at it to get some inspiration.

I'm pretty confident the same could be done to for more joints.

I am not sure yet how to do the limiting rotation part. I will take a look into limiting rotations today.

Here I have a file that locks a matrix from rotating further than specified rotation angles.

Thank you for all the responses, I will look into all of this!

kodra
Or you can write your own FBIK in APEX. People are going to tell you APEX is a super flexible system where anything is possible. (plebs who are not able or willing to do this are simply not good enough for Houdini )

I know my current limits, but I will try XD

Fraenk
Why would you need more than 3 joints for the main-arm (which is the default ik-setup anyway) + using a fk-rotation for the manipulator? You could limit the rotations using clamp-nodes.

Yes that was my plan B. It would just be easier for the animator if it can be moved by 1 ik controller.

I`d really like to limit my joint transforms in a look at right now so i guess ill have to clamp a rotation relative to rest at some place in the apex graph. It seems like a fairly eazy thing to calculate a max diference in the rotations relative to the rest skel but since its so new it`s hard to figure out how to do this.

Hi there,
Any news on that front ? APEX IK with limits and locks on axis ?

I am trying to rig a "simple" hexapod, so 6 legs with each having 3 bones.

thanks !

I am also looking for this: IK robot leg with 5 joints, each of which can only move along one axis. Perhaps we need to reach out to actual robotic engineers.

I Should find this community first.

I've spend "A LOT TIME" to try to understand how to build skeleton system in Kine-FX and APEX,
the answer is they both are super difficult, complicate and hard to understand,
but can create very complicate character set.
both also can do same basic thing with other 3D character animation software, but need spend more time for setup.

20 years ago, Softimage already build-in for skeleton system, just need few click, I guess Maya is same too.


But using Kine-Fx is super waste time, 10 mins in other software, few hours in Kine-FX for same thing.
I've try to use AEPX, It's need to build this super basic function by myself....and need to study APEX script first...WHY???


Sorry for my bad english, I am so tired and really want to cry.

https://www.sidefx.com/contentlibrary/mech-rigged-animated/ [www.sidefx.com]
In this sample file, machine legs can just rotate on single axis and it's looks amazing, however, It's .bego file, can't see how it's work.

I don't have access to Houdini right now but if you have a bgeo with the rig, you can just take it out using an Unpack Folder SOP and then look at it in the APEX Network View pane.

I'm sorry, it's almost unreadable to me, because Base.rig is too many point and too complicated.

edward
I don't have access to Houdini right now but if you have a bgeo with the rig, you can just take it out using an Unpack Folder SOP and then look at it in the APEX Network View pane.