Slide along attachment point

[llevine]

Hi there!

You can't do what you describe using attachments, as this isn't how they work. (Static) attachments set the mass of some particles to infinite (excluding them form the simulation) and overrides their position to follow a certain transform. Dynamic attachments exchange forces with the rigidbody they're attached to. Both types of attachment constrain 3 translational DOFs (degrees of freedom) and optionally, in the case of rods, 3 additional rotational DOFs.

This would be more of a "pinhole constraint" or something similar, that constrains the rope in only two translational DOFs and (I assume) all three rotational DOFs, leaving only one axis for the rope to move along. The "...when enough force..." part would also imply some kind of sliding friction along this unconstrained DOF. This is a really specialized use case.

Currently the only way of doing this would be collisions + frictional contacts.

kind regards,

Thank you! You can ignore the "when enough force" part. I understand what you're saying, and am guessing I need to implement my own pinhole constraint as a new constraint type. Could you point me in the direction of how to constrain only two translational DOFs? I see in ObiParticleAttachment that the UpdateStaticAttachment method sets solver.angularVelocities[solverIndex] = Vector3.zero. Would changing this value in 1 dimension give me what I want?