Creo Simulate > Creating Design Studies > Creating Design Studies > Optimization Study for Structure and Thermal > Design Limits
  
Design Limits
Use the Design Limits area of the Optimization Study Definition dialog box to select one or more measures to act as limits for the optimization, and to define the mathematical limit that you want Creo Simulate to observe for each measure.
Each limit that you define is a mathematical statement including the measure, an operator, and a value (for example, max_stress_prin <100). Creo Simulate seeks to keep the measures you select within the limits you specify during the study. For example, you might want to ensure that an aluminum model does not exceed 20,000 psi for avonMises stress measure. If you set this von Mises stress value as an optimization limit (max_stress_vm < 20000), Creo Simulate will move the model toward 20,000 psi in an attempt to find a more efficient model that still meets that limit, as well as any goal you set.
 
* Creo Simulate displays an error message if you have defined two or more limits with redundant or contradictory conditions.
Defining design limits is optional, but if you do not define design limits, you must define a goal. Without design limits, Creo Simulate searches for the optimum value of your goal anywhere in the full range of the design variables you select.
The Design Limits area of the dialog box includes a and button that you use to create and delete the measure limits, respectively clicking the button displays the Measures dialog box. You cannot select a measure unless you have defined an analysis for which that measure is valid. You can select measures associated with multiple analyses.
After you select a measure and exit the Measures dialog box,Creo Simulate displays the name of the Measure you select in the Optimization Study Definition dialog box and adds fields that enable you to select an Operator (<, >, or =) and Value for the measure limit. Creo Simulate reports some rotation measures in radians. You must enter the limits of rotation measures in radians (1 radian=57.29578)
 
* You can use the same measure as a limit more than once.
After you select a measure as a limit, Creo Simulate displays an analysis name below the Design Limits table, except for measures like total_cost and total_mass that are calculated for all analyses. In case of multiple analyses, you can use the Analysis drop-down list to indicate the analysis that you want the optimization study to run.
Depending on the analysis type you select, you may have the option of selecting specific load sets or modes. If you select a modal and prestress modal analysis, you also have the option of enabling mode tracking.