Creo Simulate > Modeling Structure and Thermal Problems > Model Type > Guidelines for Working with Model Types
  
Guidelines for Working with Model Types
Before selecting a model type, you should be aware of the following:
If you do not select a 2D model type, your model defaults to 3D.
If you select a 2D model type, you must select the geometry on which you want to perform a 2D analysis.
For 2D model types, you must also select a Cartesian reference coordinate system. You may need to create a reference coordinate system for your model so that the geometry you select lies in the XY plane. For 2D axisymmetric models, all the geometry must lie in the X>= 0 portion of the XY plane. for more information about specifying a reference coordinate system for a 2D model, see About Coordinate Systems.
If you change the model type after creating loads, constraints, or other modeling entities, Creo Simulate deletes all the modeling entities.
After you have selected the geometry for a 2D analysis, if you decide to change your model to 3D and then back to a 2D type, Creo Simulate will highlight the previously selected geometry.
You can perform a 2D analysis on all 2D model types.
Creo Simulate supports all analyses and design study types for 2D models, except transient thermal analysis. Large deformation static analysis is supported for 2D plane strain and 2D plane stress models, but not for 2D axisymmetric models.
You can perform a contact analysis on two disjoint surfaces.
Creo Simulate cannot perform 2D analysis on midsurface models, sketches, or sections.
Creo Simulate treats assemblies that include 2D components differently depending on whether the top-level assembly component is a 2D or 3D component. Here is a summary of the difference:
If the top-level component is 2D, Creo Simulate suppresses most simulation data from lower-level assembly components, including loads, constraints, boundary conditions, properties, and idealizations.
If the top-level component is 3D, Creo Simulate suppresses the simulation data listed above from any 2D lower-level assembly component.
If you switch between 2D and 3D model types for the top-level component, Creo Simulate suppresses or unsuppresses lower-level component simulation data according to the rules just described.