Help Question about fishing rod mechanic

[josemendez]

I watched the video you uploaded to youtube. There is no rope pulling in your video.

When we pull the rope, the rope oscillates a lot to the left and right. This is not something I want. I recorded my test scene on video below.
https://streamable.com/jx8fhe

I have no idea what's going on in your video. Could you post the code you're using for this?

I do the stretching and pulling of the rope by changing the stretching scale value of the ip under distance constraints.

Decreasing the stretching scale should definitely not result in what's seen in your video, unless you're setting it to extreme values. If should be between 1 (100%) and 0 (0%) in most cases.

When I increase the mass value in the rigidbody of the object, it swings back and forth less. But I don't want it to shake at all.
I think it is not possible to do this with obi rope. Because this operation may be against physics.

The rope will always behave in a physically driven way: if it's suddenly shortened, it will lash back/curve/jiggle as needed to maintain momentum. You can override this behavior by writing your own velocity/position values in the solver arrays, see the particles API.

This said: if you're going for unphysical behavior, using a full rope simulation for this is probably going to make matters unnecessarily complicated for you. For instance if all you need is to keep a given distance between the end of the fishing rod and the end of the line, a simple distance/spring joint is all you should use.

You can sort of mimic this in Obi by setting the rope blueprint resolution to zero, which will result in a rope with only two particles: one at the start and one at the end. But doing this is kinda like taking an motorcycle and stripping it of the engine, tires, electronics, etc to turn it into a bicycle: it's probably easier to just use a bicycle to start with.

I can do this with writing code. If you do not have a solution, I will do it with code without using obi rope.

Not sure what you mean by "doing this with writing code", you'll have to write code for this whether you're using Obi or not.