Odd faces (I think) popping out in softbody animation of rope

Question

I have been following the "Quick Noodle Physics in Blender Tutorial" by BlenderHD, attempting to make a rope with physics. I created a path, made it a soft body, and have it draping over a cube on a plane.

As just a path, it works reasonably well:

I then add a circle in another collection and connect it to the path by making the circle the "bevel" object (per the tutorial). It looks OK, but when I do the animation two weird things happen.

If I choose "3D" for the path "Shape" it looks like the thing unfolds when it drapes over the cube:

If I change it to "2D" it looks more rope-like, but has a lot of extra jaggies popping out of the cube:

I tried subdividing the cube, thinking it was some problem with having too few faces, but no joy.

Any pointers would be appreciated.

Answer 1

OK, I figured it out. Under softbody -> Solver, I changed the step size min and max way down to min 1, max 10, and error limit of 0.001. That slowed things down a bit, but got rid of the problem. Also, I noticed that this happened mostly when the rope hit the side of the box, so I increased the outer thickness to 0.2. It doesn't put out the odd vertices, but it now doesn't lay directly on the box -- it acts more like a stiff rope. I have an intuitive grasp of why this worked, but if someone reading this could explain it explicitly, I would appreciate it.