Absolute and Relative Tolerance Settings
When specifying geometry tolerance settings on the Geometry Tolerance Settings dialog box, you can specify absolute values or values relative to the model, part or feature using the following options:
• Relative to model—Specify the tolerance as a ratio of the geometric entity in question—edge, surface, or merge distance—to the size of the model. Creo Simulate determines the size of the model by measuring the diagonal length of a bounding box that surrounds the model in Cartesian space. The software measures the diagonal from the smallest XY bounding box vertex to the largest, using the WCS as the basis for the coordinate directions. In using Relative to model, take special note of how your model is oriented relative to the WCS.
While you can use Relative to model for part models, this option is primarily useful for capturing an entire assembly.
• Relative to part—Specify the tolerance as a ratio of the geometric entity in question—edge, surface, or merge distance—to the size of the part. As with
Relative to model,
Creo Simulate determines the size of the part by measuring the diagonal length of a bounding box, and you need to pay special attention to how the part is
oriented relative to the WCS.
• If you use Relative to part for an assembly, Creo Simulate calculates the bounding box and diagonal for each part whose geometry does not meet the tolerance you specify. The software adjusts the geometry for each part relative to the diagonal for that part. In the case of Merge Tolerance, Creo Simulate places a single bounding box around both members of part pairs that have mated or overlapping surfaces.
• Absolute—Specify the tolerance setting as an absolute value.

To ensure that Creo Simulate will produce usable geometry with the tolerance settings you specify, you should keep all tolerance settings within 10% of the default values for the dialog box.
