Help Pulley with Obi rope

[josemendez]

So i'm trying to simulate a pulley using the Obi rope asset.

The cubes are rigidbody with a mass of 100 (it seems that the greater the mass the better the dynamic result though I have no idea why). They are attached to the rope using Obi particle attachment (dynamic).

Mass determines what percentage of the force is applied to each object during a pair interaction (collision, constraint of any kind). If you had an object with infinite mass and a object with very small mass collide with each other, the object with infinite mass would be considered fixed (won't move) and the object with small mass would retain all the energy it had previous to the collision (assuming perfectly elastic collision). This is what happens in real life, too.

The pulley is made with 3 cyllinders: rigidbody and Obi collider so that the rope can collide with them.

It seems that the rope bounces against the pulley and then it all goes crazy. Any idea how to solve that??

Particles should not bounce against anything, as restitution in Obi is always zero. Also, should not go crazy in any way, unless you've attached particles inside a collider that's also set to collide with the rope (as explained here:http://obi.virtualmethodstudio.com/tutorials/pinconstraints.html) Can you share a video of this?

Or is it another better way to simulate a pulley??

There's better approaches to pulleys than using a traditional lumped-mass iterative constraint based solver like Obi, if we're talking about all existing algorithms. See for instance our other cable simulator, Filo: https://assetstore.unity.com/packages/to...tor-133620. But as far as Obi goes, this is the best way to simulate a pulley.