In Autodyn Component System, if the element where the gauge point sits is eroded away, you might find that this gauge point is undefined and all the variables at this gauge point are zero. So, make sure the gauge point elements are not eroded away in your calculations. If you have to put gauge points in the region where erosion occurs, please select “Retain Inertia of Eroded Nodes” in the interactions panel to avoid undefined gauge points. If the gauge type is “fixed” in space and the Lagrange part moves away, the gauge points also become undefined when these points are out of the part. Make sure at this time the gauge point type is set to “moving”.