Creo Simulate > Getting Started with Creo Simulate > Planning and Modeling Considerations > Building Part and Assemblies > Strategy: Techniques for Refining your Geometry
  
Strategy: Techniques for Refining your Geometry
Structure and Thermal element generation is the first step in the analysis of a part or assembly. Creo Simulate automatically creates elements as part of the analysis. In most cases, Creo Simulate will automatically mesh a properly built model without any user intervention. In certain situations, including models with geometric inconsistencies or small features, you can take several steps to ensure that the Creo Parametric geometry will mesh:
Make sure your geometry is fully specified, as this will help meshing succeed.
Modify the model to clean up any questionable geometry. In cases where small surfaces or edges with rounds create problems and cannot be redefined, use Operations > Replace in the Sketcher to modify the sketch, or Edit > Patch, or Model > Thicken. Adding sections to blends and sweeps and adding points in variable radius rounds may be helpful.
If auto-meshing fails within an assembly, try to assess the individual parts in Creo Simulate. This can help you determine why Creo Simulate cannot create elements—whether an individual part is creating the problem or if the assembly constraints are over constraining the automesher. If any part cannot mesh, use the suggested techniques to fully specify the geometry. Otherwise, merging touching parts that are of the same material and modifying assembly constraints may help.
Suppressing all unnecessary features reduces the total number of elements generated and may also simplify the geometry so it can mesh successfully. It is especially important to suppress features that can create small or difficult to mesh surfaces. Features likely to create these surfaces include rounds, unaligned features, and variable section blends and sweeps. Model rounds as separate features. If a round is part of the feature sketch instead of a separate feature, select the feature in the Model Tree, right-mouse click, and select Redefine to change the sketch to a straight-edged part.