I created a contact force in adams, in contact force we have 2 methods to calculate normal force, but both of them have problem in my issue. I want to create a function to calculate the normal force that the object does not cross the plane, for example in the impact formula we have F=k*x^e-c*xdot. So when the action force changes, x must change to calculate the reaction force (normal force), for example in this image I set the stiffness to Mg, the gap must be equal to 1 so that the resulting normal force equals to Mg force. Accordingly, by changing the value of applied force, x must also change; But I want these small changes not to happen and consider plane really solid. if contact not occur normal force zero, and if contact occur normal force calculate and not cross the plane. when apply general constraint: DY(Bot.cm,0,0)-70, this constraint can calculate normal force but never jumping could happened. how can I create custom function for fix this problem?