I made an animation with a spring in Blender, using a Stretch constraint. After several hours of Google searches, I’ve learned that constraints aren’t carried over into Unity, but I still haven’t figured out how to make the spring animation carry over. I put keyframes on it, but it doesn’t work. I assume it’s because the Stretch constraint doesn’t appear to affect the loc, rot, or scale.
Picture of the current animation halfway through (note that the spring is supposed to stretch along with the barrel.)