About Units in Relations
By default, relations are unit-sensitive. Unit-sensitive relations behave as follows:
If you mix parameters with different units in a relation, the system converts them in order to solve a relation. For example, if the system units are mm, and you have a parameter B with the value of 1 inch, the relation d1=B is evaluated as d1=25.4mm.
You can mix unitless parameters and parameters with units in the same relation. For example, if you have a unitless parameter A and parameter B with units, you can have a relation: d3=B*A. In this case, A is used as a scalar value. You can also include a unitless parameter and specify units directly in the relation. For example, d3=A[mm] + B.
Creo versions available before Creo 1.0 were not unit sensitive.
Checking for Units in Relations
You can set the configuration option relations_units_sensitiveto check for units when solving relations. This option has the following values:
yes (default)—Solve relations taking units into account. If units are missing, the system issues a warning.
no—Ignore units in relations.
You can control whether relations for the selected object (listed in the Relations editor) are unit-sensitive by clicking or clicking Utilities > Unit Sensitive in the Relations dialog box.
You can set the relations_units_sensitive configuration option to no, and then apply Unit Sensitive. This prevents the system from issuing error messages if units are missing.
The Verify command checks for validity of relations from the relations perspective and issues and error if units are contradictory. You can set the configuration option relations_num_const_units to issue a warning if units are missing in a relation. If the option is set to yes, the system checks for units, issues a warning, and prompts you to fix the relation by applying units.
If you want to add a relation to nonsolid models, for example, bulks, you must always specify units for numeric constants.
The setting of the relations_num_const_units configuration option is ignored for nonsolid models.