Abstract
We propose an approach for real-time physically semi-realistic animation of strings which directly manipulates the string positions by position based dynamics. The main advantage of a position based dynamics is its controllability. Instability problems of explicit integration schemes can be avoided. Specifically, we offer the following three contributions. We introduce the non-elongating and non-stretchable mass spring dynamics model based on Position Based Dynamics to simulate 1D string. We introduce a method for propagating the twisting angle along the chain of segments. In addition, we solve collision constraints by regularly distributing the spheres along the chain segments followed by particle projection to validate the positions. Proposed strain limiting constraint can handle the strings fixed in multiple locations contrary to single fixed side as is common for hair models. The use of multiple constraints provides an efficient treatment for stiff twisting and non-stretchable mass spring dynamics model.