To Create a Curve from a Surface
1. Click 
Style > > 
Curve from Surface. The Curve from Surface tab opens.
Style > > Curve from Surface. The Curve from Surface tab opens.2. Select a curve type:
◦ Free curve—Click 
, or right-click and choose Free.
, or right-click and choose Free.◦ Curve on surface—Click 
, or right-click and choose COS
, or right-click and choose COS◦ Isoline curve—Click 
, or right-click and choose Isoline.
, or right-click and choose Isoline.3. To select a location for the curve, perform one of the following actions:
◦ Click a point on the surface for the curve to pass through.
◦ Click the References tab, click the Surface collector, select a surface, and then click a point on the surface.
A curve from surface with a default orientation is created.
4. To switch the curve direction, perform one of the following actions:
◦ Click 
.
.◦ Hold down the CTRL key while you click the surface.
◦ Right-click and choose Flip.
5. To move the curve along the surface, drag the curve, or type a value from 0 to 1 in the Value box.
6. Click 
.
.7. If needed, convert a curve from a surface to another curve type by selecting the curve and performing one of these actions:
◦ Click > > .
◦ Right-click and choose Convert.