Object Manipulator not working in nested children?

[weber_aias]

Hello! I am trying to develop an app for the HoloLens 2/Windows using MRTK 3. The goal is to have a robotic arm, with 6 joints in IK and the user can grab and rotate each joint. The problem is that apparently nested logic does not work as intended with MRTK? It can’t be… When I try to select a child joint, it defaults to a parent. For some reason out of 6 joints, the first two work perfectly, and all the rest just default to the second joint, followed by warning:

A collider used by an Interactable object is already registered with another Interactable object. The T_Transform (UnityEngine.BoxCollider) will remain associated with L_BASE (MixedReality.Toolkit.SpatialManipulation.ObjectManipulator), which was registered before B_BASE (MixedReality.Toolkit.SpatialManipulation.ObjectManipulator). The value returned by XRInteractionManager.TryGetInteractableForCollider will be the first association.
UnityEngine.XR.Interaction.Toolkit.XRBaseInteractable:OnEnable ()
MixedReality.Toolkit.StatefulInteractable:OnEnable () (at ./Library/PackageCache/org.mixedrealitytoolkit.core@b62d60687f8c/Interactables/StatefulInteractable.cs:199)

A collider used by an Interactable object is already registered with another Interactable object. The T_Transform (UnityEngine.MeshCollider) will remain associated with L_BASE (MixedReality.Toolkit.SpatialManipulation.ObjectManipulator), which was registered before B_BASE (MixedReality.Toolkit.SpatialManipulation.ObjectManipulator). The value returned by XRInteractionManager.TryGetInteractableForCollider will be the first association.
UnityEngine.XR.Interaction.Toolkit.XRBaseInteractable:OnEnable ()
MixedReality.Toolkit.StatefulInteractable:OnEnable () (at ./Library/PackageCache/org.mixedrealitytoolkit.core@b62d60687f8c/Interactables/StatefulInteractable.cs:199)

This warning happens for all my nested objects.
This is my first project using MRTK so I might be missing something completely obvious but I can’t find anything, neither here nor on other websites…

Here in this picture I will try to explain! On the left you can see under “Plane” the logic of my hierarchy. In the actual game you can see, that although clearly the raycast during grab is on top of another joint, it is selecting the 2nd joint, as described. Grabbing it from up close has the same effect as well. So it doesn’t look to be a raycast exclusive issue. On the right you can see my basic setup with object manipulator and bounds control. To be clear, I am working with the basic MRTK 3 settings proposed by Unity, for both the project as well as the hands and all that stuff. Please help!

[ericprovencher]

I recommend seeing the replies in this thread. They may help solve your issue

How to hover / select a child object of a complex 3d-model

Hi, i am new in XRI Toolkit development. My problem is, that i can’t find a way to hover / select only the touched part of a complex 3d-model (consisting of a hierarchy of objects). Every time i hovers / selects the hole object (root node of object). Every node has a XRGrabInteractable component, a mesh, a collider and a rigidbody. Please help!

[weber_aias]

@ericprovencher

I recommend seeing the replies in this thread. They may help solve your issue
https://discussions.unity.com/t/931084

Yes i had already seen that, but I couldn’t really understand it! I kind of figured it out now! But now I have a new “bug”. Highlighting each child also highlight the previous parents. So for example, hovering over the last child highlights all my parents. It is not a super annoying bug, but I’d rather not have it.

In the picture I am just highlight the last joint , and on the right side I shown some of the current properties on object manipulator!

[ericprovencher]

You should be able to add a target priority filter onto your interactor, and then change the affordance provider on your interactable to enable the hover priority state.
Method IsHighestPriorityTarget | XR Interaction Toolkit | 2.5.2 (unity3d.com)