Help Scripting rod forces

[chenji]

You are right, maybe my last example was just bad.
Consider rod controlled by some input number - starts with 0, then over time goes to 5. Every update rod velocity is upated to: inputDelta / dt.
After traveling 3 meters rod hits the wall, in result force is applied, but wall stops it from moving. In the end desired input was 5, while rod stopped at 3.
Then I pulled rod back to 0 (via input) and in result rod will end up in -2. This is the second setup I had (first one was just simple rigidbody attachment) and to fix that problem I still tried to move one particle to desired position - it worked similary to static attachment, but that obviously forces rod into unstable state.
But I noticed this approach is simply wrong and I need different solution.

This is not a difficult problem. You can use Unity's joint. It can take care of all of the problems as long as you set its properties correctly. You can set the X/Y/Z limit so the rod can be pulled to 0 instead of -2. Then use a dynamic attachment in the middle of the rod to pull the rod (add force on this attachment object). Actually this is exactly what I did in my fishing game: I use this way to pull the fishing rod and it can only be pulled up to a max angle. And in fishing the rod can be pushed down to a min angle.