Guidelines for Meshing Large Assemblies
The geometric tolerance value of components in an assembly plays a vital role in meshing. If Creo Simulate fails to mesh assemblies:
Tolerance Report2. Review the tolerance report. When reviewing the report, look for significant differences in the tolerance values of components, the assembly as compared to the components, and so on. Although the difference can vary depending on the assembly, a significant difference is generally considered to be a difference in the decimal order of magnitude. For example, the difference in two tolerance values of 2.874 and 0.513 would be significant, but the difference of 0.274 and 0.513 would not.
3. Lower the accuracy value of the components that have higher tolerance values, in order to bring them closer to the tolerance values of other components.
4. If there is a significant differences in the tolerance values reported by Creo Simulate, return to Creo Parametric and click > > 
Model Properties to open the Model Properties dialog box. Click change adjacent to Accuracy and decrease the relative or absolute accuracy value for the component whose tolerance value is too high.
Model Properties to open the Model Properties dialog box. Click change adjacent to Accuracy and decrease the relative or absolute accuracy value for the component whose tolerance value is too high.To change the accuracy value for the top-level assembly, work in assembly mode and to change the accuracy value for one component, work in part mode. When working with the Accuracy command, be aware that a decrease in the accuracy value actually represents an increase in the accuracy, or precision, of the geometry. After you lower the accuracy value, the tolerance value of the component decreases as well. For more information on accuracy, see the Part Modeling area of the Creo Parametric Help Center.