# Need help with string algorthim

**URL:** <https://forum.kirupa.com/t/need-help-with-string-algorthim/287527>\
**Category:** Uncategorized\
**Created:** [May 2, 2009, 11:49pm UTC](https://forum.kirupa.com/t/need-help-with-string-algorthim/287527 "2009-05-02T23:49:01Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![johnlouis](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/johnlouis/32/568_2.png) [@johnlouis](https://forum.kirupa.com/u/johnlouis)\
**Post date:** [May 2, 2009, 11:49pm UTC](https://forum.kirupa.com/t/need-help-with-string-algorthim/287527/1 "2009-05-02T23:49:01Z")

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![](http://img5.imageshack.us/img5/8137/stringn.jpg)

In the image above, the rectangle will be dangling below the circle. The circle will be moving around, dragging the rectangle.  
I’ve applied spring physics to the rectangle, and it rotates accordingly.

My problems are:  
1.) how do I find that point in the rectangle where the ‘string’ will be attached? With it rotating, the rectangle’s center point will constantly change.  
2.) how do I make realistic ‘string’ physics?