Use the following options to set what happens when you select Curves > Intersect.
In 2D and 3D creates intersection points where the curves cross one another in the active view.
In 3D Only creates intersections only where curves actually touch one another.
Specifies which axis or view to use to create intersection points.
X, Y, and Z create intersections along the direction of the axis chosen.
Active View create intersections in the active camera view.
Free lets you specify the axis of intersection in the Direction boxes.
All Curves creates intersections for all selected curves.
With Last Curve Only creates intersections for only the last curve selected. Turn this on to create intersections where several curves overlap one curve.
Global uses the Positional Tolerance value in the Settings part of the Preferences window.
Local lets you enter a value to override the value in the Preferences window.
Several NURBS menu items provide Use Tolerance as way to increase how precisely Maya creates a curve or surface. For example, you can create a revolved surface with a preset number of sections or you can enter a low Tolerance value to create more surface sections.