A. Zoom in a bit further on the Front viewport. Change back to rectangular selection by clicking the Rectangular Selection Region button on the main toolbar. Select the edges as displayed in the following image. Do not click on the edge but draw a selection rectangle as you also need to select the same edge on the other side of the rim. |
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| B. Click the Loop button to select the entire rows of edges. |
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| C. Click the small square button on the right of the Chamfer button in the Edit Edges section on the Modify tab to open the Chamfer Edges dialog box. Change the Chamfer Amount to 7 and click Apply. Change the Chamfer Amount to 3 and click OK. |
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| D. Select the edges as displayed in the following image. Do not click on the edge but draw a selection rectangle and click the Loop button as you also need to select the same edge on the other side of the rim. |
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| E. Click the small square button on the right of the Chamfer button in the Edit Edges section on the Modify tab to open the Chamfer Edges dialog box. Change the Chamfer Amount to 2 and click OK. |
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