Free Interaction

For static, nonlinear, frequency, and buckling studies, a free interaction does not impose any restrictions on the relative motion between the components. For thermal studies, the program prevents heat flow due to conduction through contacting areas. For static and nonlinear studies, the applied loads can cause interference of components or bodies.

Applying a free interaction at a global-level or component-level can reduce the solution time if the applied loads do not cause interference. However, the results are invalid if the applied loads cause interference.

Do not use this option for structural problems unless you are absolutely sure that interference will not occur.

You get wrong results if loads cause objects to interfere.
Objects do not interfere during loading.