Fixed Joint 2D cannot stop Dangling (like a spring?)

Unity Engine
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1

I used fixed joint 2d to connect various parts of my spaceship together. whenever a part is hit, the whole ship will be pushed to the opposite direction. And ship components could be added or destroyed individually.

However the fixed joint 2d doesn’t fix the relative position and angles for 2 rigidbodies, it seems to work like spring, dangling around. in some situations, it will create a total mess. any idea what I’m doing wrong or how should I get around it? thanks in advance

issue demonstrated in the following gif: I started the thruster on the right, pushing the thruster to the left, (expect to bring all the ship left) results in a mess
9843867--1416519--fixedjoint2d.gif

my code for adding fixed joint 2d

9843867--1416522--upload_2024-5-19_10-56-2.png
9843867--1416522--upload_2024-5-19_10-56-2.png781×308 16.3 KB

2

I am very confused by joint.frequency = 1_000_000. Setting it to 0 is sufficient for an unbreakable fixation.

3

I was trying out different parameters, 0 or 1e6 doesn’t make a noticeable difference to me

4

Then likely you’re using large mass-ratios, directly modifying positions via the Transform/Rigidbody, using huge forces, not increasing solver iterations (especially when using chains of joints) etc.

Clearly the FixedJoint2D doesn’t do that normally (explode) but it’s not difficult to narrow down how you’re causing it problems.

Spin-up a project add “2 rigidbodies” and see it doesn’t happen. Then start doing whatever you’re doing above.