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+--- Thread: Help Extending rope by pulling on cursor end (/thread-4584.html)
Extending rope by pulling on cursor end - trentthebaker - 09-01-2026
Hi there,
I've recently been learning the ropes of Obi Rope and am very excited to work with it! I have a question that I haven't quite found a satisfying answer to. I have a rope which is attached to 2 rigidbodies with dynamic particle attachments. For testing, Body A is kinematic and Body B is not. I want to extend the rope when Body B is moving such that the rope is taut and needs more length to keep up- that is, Body B is pulling the rope out of the cursor (inside Body A), ideally with little resistance. I've attached a video to demo what I'm trying to achieve.
I've tried comparing CalculateLength() to restLength and adding the difference if it's positive, which seems to work in some situations, but there are false positives when applying force to Body B while there's still slack. My understanding is that the end of the rope is stretching to keep up with its pin making the calculated length greater than rest length, despite there being slack left to use. I only want this extending to happen when I would realistically expect the rope to be pulled at the cursor point. Writing now, I suppose there just has to be force applied to the line where Body A/the cursor is, there could be slack further up the line.
I believe this is a solvable problem, while searching the forums I found this demo: https://obi.virtualmethodstudio.com/forum/thread-4062.html
When the fishing line is cast out, there's no perceivable resistance, that's the sort of effect I'm hoping to achieve.
Afterwards, and this may be the same solution, I'd love to implement retracting as a means of force rather than distance/time, that is, if Body B is massive or has opposing force then it is harder to retract.
If there's any further clarification or code that would help explain I'm happy to share!
Thanks
I don't see my file attachment in the final post so here's a Google Drive link just in case: https://drive.google.com/file/d/12stx-FVRr0GFRPjZvsl4Jj7stZN9RjVX/view?usp=sharing