To Construct a Curve Based on an Iso-Parametric Line from a Surface

Select the Extract Iso-Curves tool ( Modeling > Surfaces > Surface Utilities > Extract > Iso-Curves ).
In the tool settings, set Extract to Single Curve.
Select the surface.
As you move the pointer, an iso-curve in the u-direction displays dynamically.
Do one of the following:

Enter a data point to define the curve's position and create the iso-curve in the u-direction.

or
Reset to display an iso-curve in the v-direction.

As you move the pointer, an iso-curve in the v-direction displays dynamically.
Enter a data point to define the curve's position and create the iso-curve in the v-direction (or Reset to create no curve).

(1) Select the surface. (2) Enter a second data point to position the iso-curve.