Unsure if it's appropriate to bump an old thread like this, but I'm having the exact same issue and there was no resolution in this thread.
In my case, this is happening if I have two obi rope solvers in the scene. The first one renders fine, and the second renders fine on the first scene load, but subsequent scene loads cause the rope to not physically render in development or play mode. Very strange and a bit of a blocker - I'm creating a scene with multiple different rope categories and want them to have different properties. Like OP they render these thin white lines in the scene, but the actual rope with texture and thickness is missing.
Update: I think I solved this by changing two things. I'm not sure which ended up being "the" solution.
1. My first obi rope setup was part of a prefab. I unpacked the prefab.
2. Under the "working" solver that never broke, I created the rope I wanted to. Then, I transferred my rope to the solver that frequently had rendering issues.
After these two steps, I haven't had the problem.
In my case, this is happening if I have two obi rope solvers in the scene. The first one renders fine, and the second renders fine on the first scene load, but subsequent scene loads cause the rope to not physically render in development or play mode. Very strange and a bit of a blocker - I'm creating a scene with multiple different rope categories and want them to have different properties. Like OP they render these thin white lines in the scene, but the actual rope with texture and thickness is missing.
Update: I think I solved this by changing two things. I'm not sure which ended up being "the" solution.
1. My first obi rope setup was part of a prefab. I unpacked the prefab.
2. Under the "working" solver that never broke, I created the rope I wanted to. Then, I transferred my rope to the solver that frequently had rendering issues.
After these two steps, I haven't had the problem.