The buttons on the Snaps Toggle provide control over the range of 3D space where snaps are active. A wide variety of snap types is available from the , which you can use to activate different snap types as you work.
2D, 2.5D, 3D Snaps flyout
Object snapping lets you snap to specific portions of existing geometry during creation and transforms of objects or sub-objects. You can also snap to the grid, and you can snap to tangents, midpoints, pivot points, face centers and other options.
When snapping is on and is off, rotations and scales occur about the snap point. For example, if you're using Vertex snapping and you're rotating a box, you can rotate it about any of its corner vertices. See below.
A circle at the center of the Move gizmo shows that snaps are active.
Not only does the circular handle indicate that snaps are active, it helps increase the accuracy of snaps, compared to releases prior to Autodesk 3ds Max 2011. You can use the gizmo controls as before, or drag the handle itself: In either case, 3ds Max shows the original position of the object, and by default a rubber-band line stretches from the original position to the new destination. When you drag the snap handle or the Move gizmo, the axis center is the start snap point.
The green line shows start and destination points.
Dragging from the snap handle is equivalent to using the Use Axis Center As Start Snap Point that was available in versions of 3ds Max prior to Autodesk 3ds Max 2011. In addition, you can use other snap points on the object that you are moving. For example, when snapping to vertices, the following illustrations show that you can snap from a vertex on the object you are moving.
Vertex snap: Snapping from the upper-left corner of the box.
Snapping the upper-left corner of the box to a vertex on the dodecahedron.
Using the snap handle or the Move gizmo corresponds to the toggle , or to (Snaps Use Axis Constraints Toggle) on the being on. Using a snap point elsewhere on the moving object corresponds to the option being off. In Autodesk 3ds Max 2011, buttons on the toolbar update interactively, depending on which portion of the gizmo or geometry you use to move the object.
Suppose you create a and make it active. You then position the grid object so you can see through the grid to a cube further off in 3D space. Now with 2.5D set, you can snap a line from vertex to vertex on the distant cube, but the line is drawn on the active grid. The effect is like holding up a sheet of glass and drawing the outline of a distant object on it.