I am working on a linear dynamic study that had some parts captured by springs, and a few questions about spring connectors came up. Could some one explain why you can only defined stiffness as distributed in linear dynamic studies? I can't quite wrap my head around it, and the help files really don't explain what it is, and how to use it. Additionally, why can't I define a pre-load value for my spring? I am working with a McMaster spring, so the only values I get are spring constant and minimum load.