I am trying to run a dynamic simulation on a roll cage for my senior project. I am impacting the cage with an object at a specified speed. However I am running into the issue of initial contact between the surfaces. It seems there is no contact. When I use the contact tool I get the error 'invalid entity on beam body was selected." I think it has to do with the fact that the cage is built out of weldments. I read the other post on this and have no idea what their trying to say. Any suggestions?