# Defining Initial Simulation Studies

When using simulation data sensors in a Design Study, you create at least one initial study. Initial studies represent the basis for the optimization or the evaluation process. During each iteration, the program runs these studies with modified variables.

The required initial studies depend on the constraints and goals you select. For example, a goal to minimize the volume or weight does not require an initial study of a particular type, but a goal to minimize the frequency requires an initial frequency study. The frequency simulation study provides the information to the frequency sensor to be used by the Design Study.

The same rule applies to constraints. Each constraint you specify must be associated with a compatible initial study. For example, to define constraints on stress, frequency, and temperature, you must define static, frequency, and thermal studies, respectively.

All studies referenced in defining constraints and goals must belong to the same configuration.

After creating your model and dimensioning it to the best of your knowledge, create the initial studies and define their properties, materials, loads, and restraints. It is not recommended to use more than one study of the same type in an optimization problem.