I am new to the forum. My name is Michael
I cannot figure out a good method to rig a metal spring for a 1930s cartoon character I am working on.
It is a Jack in the Box-type character.
I did a couple of test rigs using transform/path constraints, but the results were not good at all.
The test was more of a straight-on profile view because I thought it would be easier, but I would prefer the spring rig to be more like the concept if possible.
Thank you!
mlee_808 Welcome to the Spine forum! I think there are several possible way for rigging springs, but here is what I think is probably the easiest of them all:
Using an IK constraint, you can create a bone that be stretched and compressed when you move the target bone. You can use this to create the entire movement of the spring:
The yellow circle is intended to be Jack's head.
Create some bones as the child of the constrained bone by the IK constraint. These bones will be bound to the mesh attachments of the spring. Turn off scale inheritance of these new bones:
Then, you can get a bones movement like the following animated GIF:
You can bind these bones to the mesh attachment for the spring, and if you set the weights appropriately, you should get the following movement as a result:
As a note on setting the weights, the vertices closer to the root are given more weight for the root bone for the spring so that the tip of the spring stretches more and the root does not stretch as much.
You can download this sample Spine project here:
I hope this will be helpful to you.
Hey Misaki,
Thank you so much for your efforts and help.
Here are the results
Thank you again 
