Creo Simulate > Modeling Structure and Thermal Problems > Regions > Surface Region > Before You Assign a Surface Region
  
Before You Assign a Surface Region
Here are some factors to be aware of when you work with surface regions:
If you add surface regions to a fully periodic surface such as a cylinder, cone, or sphere, all the segments that make up the surface are selected. When you create a surface region on a periodic surface, Creo Simulate creates 2 surface regions, one on each segment of the periodic surface. If you want to create only one surface region on just one half of a periodic surface, create a quilt surface in Creo Parametric on one segment of the periodic surface. When creating a surface region in Creo Simulate, select the quilt surface as the parent surface on which you create the surface region. For Creo Simulate to use the surface region created using a quilt during meshing, you need to create a shell idealization for the quilt surface.
When you add or remove a region for a surface you already defined as part of a shell model pair, Creo Simulate invalidates the associated pairing scheme, and informs you of the situation. Thus, if you plan to treat your part as a shell model, create all regions before pairing your part surfaces.
If you cannot avoid adding or removing a region associated with a paired surface, redefine your pairing scheme to include both the region and parent surface as part of the pair before starting Creo Simulate analysis. For information on how the software creates shell pairs, see Pairing Schemes.
If you plan to place loads on surface regions for a shell model, see Model Entities and Idealizations for information on how Creo Simulate processes this type of load.
When you add a region to a surface that already has a constraint, load, or contact, Creo Simulate associates the modeling entity with both surfaces. The program adjusts the constraint, load, or contact icon according to the new placement of the entity.
Thus, if you add a region to a surface, be sure to review any associated constraint, load, or contact placement. Otherwise, the load the surface sees may not be what or where you expect. In the case of constraints, the constraint may no longer be sufficient to prevent rigid body movement.
Return to Surface Region.