To Define a Radius Using a Reference
In addition to dragging radius handles, or typing or selecting distance values, you can define a radius by snapping to a vertex or datum point.
1. Select the placement references for the round and click > 
Round. The Round tab opens.
Round. The Round tab opens.2. In the graphics window, select the radius handle of a Constant or Variable round that you want to redefine.
3. Hold down the SHIFT key and drag the radius handle to snap it to a vertex or to a datum point. As you drag, notice that the reference is pre-highlighted as your cursor moves over it. This enables you to target the correct reference. The system does the following:
◦ Replaces the default radius handle with a special handle in the graphics window that contains the reference information.
◦ Activates the Distance collector on the Round tab to indicate that an item has been selected.
◦ Selects Reference in the Sets tab distance box and populates the Radius table Distance collector with the reference information.
 | If you snapped the handle, notice the snapping behavior. For Constant and Variable rounds, the system hides the second radius handle and the radius anchor. For D1 x D2 Conic rounds, the system separates the handles and displays the unsnapped handle with the anchor to enable the handle to move independently. |
4. To redefine the radius, hold down the SHIFT key and drag the handle to unsnap it from the reference. Notice that the default radius handle replaces the special handle. You can then snap the radius handle another reference, drag the handle to a preferred location, or type or select a new radius value using the value boxes from either the Round tab (Constant rounds only) or from the Radius table on the Sets tab.
5. The radius is defined. You can continue to work with rounds or click 
.
.| | • If you prefer to define a radius from the Sets tab, select the radius to define in the Radius table # column and select Reference from the Distance box located under the table. After the distance collectors activate, select the datum point or vertex from the graphics window. • To quickly identify a radius from the Sets tab, place your cursor over a radius number on the Radius table # column. The system dynamically highlights each radius enabling you to select it. • If you want to use a datum point, but one is not present, you can create one without closing the Round tool by clicking >  Datum >  Point and opening one of the Datum Point tools.• As you work in the graphics window, you can use Clear from the shortcut menu to clear all references from the active collector. • To remove a reference from within a collector, select the reference that you want to remove, and with your cursor still in the collector, right-click and choose Remove from the shortcut menu. |