Softbody not working for Plane and Rope

[warunyoud]

Hi @notrabs, I am wondering why the mesh for some of the shapes, when using softbody, only appear for a few milliseconds after starting then suddenly disappears. For instance, https://codesandbox.io/s/use-ammojs-rope-example-wb9cg, with the rope example, I only see the rope for a tiny amount of time. The other example is when I try to use plane to imitate https://threejs.org/examples/?q=cloth#physics_ammo_cloth. The plane has the exact same issue. However, when I switch to a box with a very small thickness to simulate clothes it works. Thank you very much in advance.