Thank you for the quick and detailed answer!
I did fix the rest length issue, but I'm afraid it was not the main problem... To be sure, I created a new obisolver, added your short rope preset, and added your custom script, it seems there is still an issue... Depending on where I put the obi cursor, it either doesn't spawn new particles (if the cursor is on the wall attachment, which makes most sense to me), or spawns them but doesn't simulate them (when the cursor is on the object)... Here is a video with the two configurations. I have the same result with your obiropereel script.
EDIT : Okay, it seems it was because the cursor must not be at the very end, but on the second particle, otherwiste I guess the attachment messes with it...
I did fix the rest length issue, but I'm afraid it was not the main problem... To be sure, I created a new obisolver, added your short rope preset, and added your custom script, it seems there is still an issue... Depending on where I put the obi cursor, it either doesn't spawn new particles (if the cursor is on the wall attachment, which makes most sense to me), or spawns them but doesn't simulate them (when the cursor is on the object)... Here is a video with the two configurations. I have the same result with your obiropereel script.
EDIT : Okay, it seems it was because the cursor must not be at the very end, but on the second particle, otherwiste I guess the attachment messes with it...