Model-Based Definition > Model-Based Definition > Creating Various Annotation Types > Tolerances > Working with Dimensional Tolerances > Changing Tolerance Values > Tolerance Table Reference
Tolerance Table Reference
All instances in a family share the same set of tolerance tables, the same tolerance standard, and the same class. When changing the tolerance table reference, remember the following:
If you modify model units, but keep all of the dimension values the same, the system updates the tolerance values to reflect the change in the overall model size.
If a Holes or Shafts tolerance table drives the tolerances of a dimension, you can not show it in a plus-minus symmetric format. The system assumes that the General and Broken Edge tables have symmetric values.
If you place a dimension tolerance in a Family Table, the system deletes its tolerance table reference. Also, if you switch a model from ANSI to ISO, or vice versa, it preserves the tolerances in the Family Tables and does not assign table references to those dimensions.
If a dimension value falls outside ranges specified in the table, the system uses the closest range to obtain tolerances (that is, it uses the last range in the system table (2000–4000) to determine tolerances for dimension values of 2000 or greater).