The snap modes “snap” or lock movement/placement of objects and points.
|Snap to...||Hold||Or click|
|Curves, isoparametric curves, surface edges, or curves-on-surface. When the appropriate options are turned on, can snap to curve divisions, pivot points, or bounding box center, as well as curve intersections (true or projected).Also snaps to construction planes (see below).||+ (Windows) or + (Mac)|
|Grid intersections.||(Windows) or (Mac)|
|CVs, edit points, pivot points, locators.||(Windows) or (Mac)|
Click on the small arrow to the right of the icon to open a window with the following options.
You can use arc length snapping on curves (snap to the midpoint, 1/3, 1/4, etc) by setting Snap Divisions to a value from 0 to 100. For example, setting this value to 2 and then using snap gives you a “snappable” point (shown as a light blue line segment) halfway along the curve.
When this option is turned on and you click on a curve, the center of the curve’s bounding box is displayed as a small cross surrounded by a circle. Moving the cursor in close proximity of the center icon lets you snap to it.
When this option is turned on and you click on a curve, its pivot is displayed. Moving the cursor in close proximity of the pivot icon lets you snap to it.
You can snap to both the scaling and rotation pivots (if they are not in the same location).
When this option is turned on, you can snap to the intersection points between curves in any orthographic or perspective view, even if the curves don’t truly intersect in world space. These intersection points are displayed as pink crosses.
In orthographic windows, you can snap to the horizontal or vertical level of the thing you click, instead of its exact position:
For example, you can line up three CVs along the same horizontal line without affecting their vertical positions:
The picked CVs move to snap to the vertical position of the CV you clicked, but keep their own horizontal position.