TY - JOUR AU - Jonquet, Antoine AU - Nocent, Olivier AU - Remion, Yannick PY - 2008 DA - 2008// TI - The art to keep in touch: The ''good use'' of Lagrange multipliers JO - JVRB - Journal of Virtual Reality and Broadcasting VL - 4(2007) IS - 15 KW - Contact Simulation KW - Physically-based animation KW - constraints AB - Physically-based modeling for computer animation allows to produce more realistic motions in less time without requiring the expertise of skilled animators. But, a computer animation is not only a numerical simulation based on classical mechanics since it follows a precise story-line. One common way to define aims in an animation is to add geometric constraints. There areseveral methods to manage these constraints within a physically-based framework. In this paper, we present an algorithm for constraints handling based on Lagrange multipliers. After few remarks on the equations of motion that we use, we present a first algorithm proposed by Platt.We show with a simple example that this method is not reliable. Our contribution consists in improving this algorithm to provide an efficient and robust method to handle simultaneous active constraints. SN - 1860-2037 UR - http://nbn-resolving.de/urn:nbn:de:0009-6-12767 DO - 10.20385/1860-2037/4.2007.15 ID - jonquet2008 ER -