Joint with SolidReference as endPoint inside mechanical loop gets unlinked when there's a SliderJoint in the loop

[IDavGal]

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Describe the Bug A joint where the endPoint is a SolidReference, inside a mechanical loop that has a slider joint in it, acts as if there wasn't joint at all.

Steps to Reproduce

1. Open the attached project file [example_project.zip]
2. Wait for the controller to move the LinearMotor up and down
3. Corroborate that the corresponding solids are not attached by the joint where the SolidReference is specified

Expected behavior In the example given, 2 robots are spawned, each with a different joint having a SolidReference as endPoint. In each case, both upper and lower beams start points are connected to the base_link with a hingeJoint, while the sliderJoint is also connected to each beam's outer end via hingeJoints. I would expect the upper beam to rotate around the joint that links them to the base link when the sliderJoint extends. Instead I see that the beam moves as if no joint was specified

Screenshots Initial state:

Extended sliderJoint:

System

• Operating System: [ Linux Ubuntu 20.04]
• Graphics Card: [e.g., NVIDIA GeForce RTX 3050 4 GB]

Additional context

• I think this may be related to this older issue
• A similar mechanism with a solid instead of a SliderJoint works as expected
• A diagram is provided to better illustrate the mechanical loop

[IDavGal]

Hi! Any update on this?

[stefaniapedrazzi]

I didn't have the time to inspect the issue yet.

From my first quick inspection it seems that I can get the exact same behavior replacing the SliderJoint with a `HingeJoint. Then, I see that in your example all the Solid nodes are kinematic. Do you get the same behavior properly setting the boundingObject and physics nodes for the Solid in your robot?