To create a fillet with a specific radius

1. Double-click the Fillet Curves icon, or choose Curve Edit > Create > Fillet Curves ❒ from the Palette.
2. Set Construction to Circular, then click Go.
   
3. Click the first curve approximately where you want the fillet to touch the curve.
   

   If the two curves intersect, click the segment of the first curve that you want to create a fillet for. If Trim Curves is on, click the segment of the first curve that you want to keep.

4. Click the second curve approximately where you want the fillet to touch the curve.
   

   If the two curves intersect, click the segment of the second curve that you want to create a fillet for. If Trim Curves is on, click the segment of the second curve that you want to keep.

   Alias displays a preview of the fillet.

   
5. If you want a different radius from the default (displayed in the prompt line), type the new radius, or drag the mouse to change the radius interactively. Dragging the mouse left or down decreases the radius. Dragging the mouse right or up increases the radius.
   

   If the current radius is too small or too large to build a fillet near the point you clicked, the Fillet Curves tool reports an error. Type a new radius and try again.

   If you do not want to create the fillet, select Pick > Nothing.

6. Click Accept.

   Alias builds the fillet.

   When the fillet is built, the original curves are trimmed to both ends of the fillet. To keep the curves intact, turn off the Trim Curves option.

To create a fillet between two specific points on the curves

1. Double-click the Fillet curves icon, or choose Curve Edit > Create > Fillet Curves ❒ from the Palette.
2. Set Construction to Freeform, then click Go.
   
3. Click the first curve at the point you want the fillet to begin.
   
4. Click the second curve at the point you want the fillet to end.
   
5. Curve locators appear on the two curves where you clicked.
   • Drag the locators to move the contact points of the fillet on the curves.
   • Click Go to create the fillet.
     
6. If Blend Control is on, after the fillet is created you can click the Tangent and Blend buttons in the bottom right corner of the view window to see the different types of fillet. Click Go again to finish the fillet.

Tips and notes

• If Create History is on in the options, you can edit the curves and the fillet automatically updates.

Curve Fillet Options

Construction

Circular – Create a circular fillet with a true radius.

Freeform – Create a fillet between two contact points.

Circular + Lead – Create a circular fillet by specifying the radius where the fillet blends with the original curves (Lead Radius) and the radius at the knee of the fillet (Radius).

Freeform Type

Tangent – Project the tangents at the two contact points, and create the fillet in the direction of the tangent intersection.

Blend – Average the positions of the two contact points to create the fillet. Blend fillets sometimes have an inflection and tend to be shallower than Tangent fillets.

Radius

The default radius of circular fillets. You can enter a new value at the prompt line when you use the tool.

Calculate

Lead Radius – When you set the Radius value, Alias automatically updates the Lead Radius value.

Knee Ratio – When you set the Radius value, Alias automatically updates the Knee Ratio value.

Lead Radius

The radius of the fillet where the fillet blends with the original curves.

Knee Ratio

Specify a radius at the center (or knee) of the fillet as a ratio (or multiple) of the original radius.

The resulting fillet is not truly circular, but its endpoints correspond to the endpoints of a circular fillet with the original radius.

Blend Control

Allows you to change the fillet type (Tangent or Blend) after it is created.

Trim Curves

Automatically trim the original curves back to the endpoints of the fillet.

Create History

Save the Fillet curves history for later editing. If you turn on Create History, you can edit the original curves and the fillet automatically updates.