Draw an arc tangent to a curve

1. Choose Keypoint Curve Tools > Arcs > Arc Tangent to Curve.
2. Click the start point of the new arc on the curve it will be tangent to.
   
3. Click the end point of the arc, or type a 3D coordinate to place the point exactly.
   
   • Click the button to add the point freely.
   • Click the to align the point horizontally to the first point.
   • Click the to align the point vertically to the first point.

   As you drag the end point, the Arc Tangent to Curve tool displays the radius of the arc in current linear units.

Draw an arc concentric to another arc

1. Choose Keypoint Curve Tools > Arcs > Concentric Arc.
2. Click the arc from which the new arc will be offset.
3. Click the start point of the arc, or type a 3D coordinate to place the point exactly.
   

   As you drag the start point, the Concentric Arc tool displays the distance between the two radii.

4. Click the end point of the arc, or type a 3D coordinate to place the point exactly.
   

What if...?

• I want to create a concentric arc of more than 180 degrees?

  Concentric arcs are usually drawn in the direction that will create the smallest sweep angle.

  To draw an arc in the opposite direction, choose Windows > Information > Information Window. Open the Attributes section and click Complement.

• I want to create a concentric circle?

  Choose Windows > Information > Information Window. Set the Angle/Sweep attribute to 360.