Gravity Collider makes adding bone physics easy in simply 2 clicks! Skirts, hair, armor jiggling, breasts, keychains, all kinds of stuff gets basic physics using boxes set up in a bead necklace formation. The collision boxes are quickly adjustable whenever or however you want and weight painting them is painless and powerful.
Runs in real time due to how light it is, scales with the model, and even exports with your animation into game engines perfectly. On top of all this, because it uses ik, you can gradually turn off the physics for full control at any moment you need and gradually turn them back on again. No need for a perfect run, just go animate!

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Personally, i've been looking for a physics system setup that could add physics quickly and scale with the model for my personal needs. But each physics setup had something missing like easy to set up but can't scale, scales but no collision, runs in real time but can't export the technique to game engines, etc. I spent years testing all these options only to find that none of them worked enough to save me from manually animating everything. On top of this, I feel like adding physics to imported characters is a massive pain in Blender where I couldn't recommend it to animation newcomers because it's just not easy and heavily time-consuming.

Gravity Collider was made to break down that barrier. (With a cool name of course)

Now newcomers can skip so much of the painful learning process with physics and just focus on animating until they're ready for the deeper stuff. Which is why MinEval (Coder) and I (Workflow Creator) decided to make this free to try or pay what you want because it's an important plugin for everyone. If this helps you then please help spread the message!

There is a free download on Min's Github if you'd like to check it out:

Min's GitHub: https://github.com/MiniEval/Bone-Physics

(Blender 3.1+, but DOES work in Blender 2.8 with a traceback warning that doesn't seem to effect general usage at first glance)