You have learned how to draw electric field line from http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=539.0<br /><br />You can use the same method to draw magnetic field line.<br /><br />I tried to open ejs model from your jar file. However, I was not able to understand what you were doing in the model (evolution page: lambdax, lambday, lambdaz???)