Hi, I have a problem with the definition of mass on my system when I am in Assembly Design. I want to simulate some basic system with Mechanical System Experience. I have previously defined a kernel material on every component of the system, and when I use the measure of inertia tool, the mass of every component was calculate. But when I use the B.I. Essential tool, the mass of every component is missing. But if I want to calculate a dynamic scenario, the definition of the mass must be calculate. Sometimes, it's works well, and the next week, it's don't work... Someone can help me ?