Isoparametric Curve is a curve that is associative with the surface on which it is created. Changing the surface (support) will change the curve. To create the curve, you need to click on the Isoparametric Curve located inside the Curves tool group.
The menu opens where it is necessary to define the parameters of the curve:
By clicking on the surface (in the figure below Join.1), the appearance of the curve is displayed, the cursor moves and the appearance of the curve changes. A manipulator with which the curve can be moved is displayed. If more than one surface is selected as a support, the selected surface is a reference, and then the manipulator can only be moved along the reference surface.
The right-click menu opens the context menu.
Edit – allows you to define a curve according to the parameter
Keep this point – allows you to create a point where it clicks.
Swap UV – allows you to replace U and V parameters of the curve.
Clicking on Swap UV changes the direction of the curve (figure below). This command is available in the curve definition menu.
Point and Direction can be edited by clicking on the icons next to the boxes