Create and modify 3D models > Create 2D geometry > Change 2D geometry > Change the radius of a circle or an arc
  
Change the radius of a circle or an arc
1. Click Modeling and then, in the Modify 2D group, click Radius. The Change Rad/Dia dialog box opens.
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To change from the radius mode to the diameter mode,
• Click on the status bar or
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When you change from the radius mode to the diameter mode , the following circle commands change:
• On the Modeling tab, in the Modify 2D group, Radius changes to Diameter.
• On the Modeling tab, in the Draw group, the Circle Center & Radius changes to Center & Diameter.
• On the Modeling tab, in the Draw group, the Construction Circle Center & Radius changes to Center & Diameter.
2. Select a circle or an arc in the viewport.
3. Move the cursor in the desired direction to change the radius of the circle or the arc. In the diameter mode, move the cursor to change the diameter of a circle.
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• Click Keep selected Geometry in the Change Radius dialog box to retain the original position of the element in addition to the final position. Press K to select or clear Keep selected Geometry. By default, Keep selected Geometry is not selected.
• Click Fix Arc Endpoints in the Change Radius dialog box to fix the end points of the arc. The center of the arc changes as you change the radius of the arc.
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• You can press SPACEBAR or the assigned key to open the Option Mini Toolbar (OMT) and click (Keep selected Geometry) on the OMT to retain the original position of the element in addition to the final position.
• You can press SPACEBAR or the assigned key to open the OMT and click (Fix Arc Endpoints) on the OMT to fix the end points of the arc.
4. Click again when the circle or the arc has the desired radius. You can also type a value for the radius and press ENTER.
5. Click to complete the operation.
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• Select a circle or an arc in the viewport, select (Radius) on the Command Mini Toolbar (CMT), and click a point on the viewport to change the radius.
• Select a circle or an arc in the viewport and drag the blue highlight on the circumference of the circle to the desired position to change the radius of the circle. For an arc, drag the blue highlight on the arc to the desired position to change the radius of the arc.
• Select a radius or a diameter dimension and drag the 2D CoPilot to change the radius of an arc or a circle.
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When you change the radius of an arc, Creo Elements/Direct Modeling does not automatically stretch any 2D geometry elements connected to the end points of the arc.