Preparing a 2D Model
There are several good reasons for treating your model as a 2D model rather than a 3D model. One of the most compelling is the simplicity of 2D models from a meshing and solution perspective.Creo Simulate can solve your model in a fraction of the time it would take to mesh and solve a 3D model. However, 2D modeling is a specialized form of simulation modeling and is appropriate only if your model displays certain geometric, constraint, and load characteristics.
If you plan to perform 2D analysis on your model, you must first define your model as a 2D model type using the Model Setup dialog box. You activate this dialog box by selecting > 
Model Setup if you want to convert a 3D model to a 2D model during your simulation session. When you define your model as a 2D model, you use the Model Type dialog box to select the geometry on which you want to perform the 2D analysis and a reference coordinate system. As you prepare your 2D model, be aware that the geometry you select for analysis must be coplanar, and the reference coordinate system must be Cartesian.
Model Setup if you want to convert a 3D model to a 2D model during your simulation session. When you define your model as a 2D model, you use the Model Type dialog box to select the geometry on which you want to perform the 2D analysis and a reference coordinate system. As you prepare your 2D model, be aware that the geometry you select for analysis must be coplanar, and the reference coordinate system must be Cartesian.You may need to create a Cartesian reference coordinate system for your model so that the geometry you select for 2D analysis lies in the XY plane. For 2D axisymmetric models, all coordinates must be positive in X. To read more about specifying a reference coordinate system for your model, see About Coordinate Systems.
You cannot perform 2D analysis on midsurface models, sketches, or sections. If you have a sketch on which you want to perform 2D analysis, you can extrude the sketch into a solid in order to carry out a 2D analysis.