To Define an Element
After you select the type of element to assemble from the element library, you must define it using the relevant Element Definition dialog box. The element preview in the definition dialog box has numbered placement references and lettered dimensions and options.
1. Check the references by following the number on the preview to the reference on the model.
2. If reference collector is not active, click the collector to activate it.
3. Select the reference. The selected reference is highlighted.
4. Repeat the above steps for all required references and for optional references as needed.
5. Click the Settings tab to define dimensions and options for the element.
6. Select information from the tables at the bottom of the dialog box. The selected data appears at the top of the table. Ensure that the data is selected from each available table.
7. Select or clear check boxes.
8. Enter values, if required. A question mark (?) indicates that no value is specified for the dimension. You can overwrite default values. When a specific value appears instead of the question mark (?) in the value box, the value is driven by a table selection. After you make all selections, you can change a table-driven default. A changed value reverts to the default if additional selections are made from the table.
9. To determine an input value by measuring the model, follow the steps below:
a. Under Enter Values, click a value box.
b. Click 
instead of entering a value.
instead of entering a value.c. Select one or two points, vertices, curves, or edges as described below:
▪ Diameter is measured when you select one circular edge or a curve.
▪ Length is measured when you select one non circular curve or an edge.
▪ Distance is measured when you select two elements.
After making your selection, the result of the measurement automatically appears in the box.
10. Perform one or more of the actions listed below:
◦ Click Preview to see a preview of the Creo Parametric model with the element that you created or modified. This preview includes all holes, cuts, and so on. The Element Definition box remains open so that you can make additional changes if required.
◦ Click OK to permanently create or modify the element with all holes, cuts, and so on in the Creo Parametric model. The Element Definition dialog box closes.
◦ Click Cancel to stop the operation. If the element is created as a preview, the preview disappears. No changes are made to the model and the Element Definition dialog box closes.