Available with 3D Analyst license.
The snapping environment for editing inside ArcGlobe and ArcScene is known as classic snapping.
Snapping is an editing experience that is used to establish the exact location of new feature vertices in relation to other, already-existing features. For example, you can snap the start point of a new street feature to the endpoint, edge, or vertex of an existing street line with reassurance the line segment connection is precise.
ArcScene and ArcGlobe use classic snapping, which refers to the snapping functionality available in edit sessions at ArcGIS 9 and earlier. You select a layer and snap types using the Snapping Environment window to specify the snapping settings. ArcMap still offers classic snapping (but it is off by default) in addition to the new Snapping toolbar.
Classic snapping in 3D also has some subtle differences when compared to the 2D environment. For example, rather than showing the final snap location in 3D, the sketch pointer simply changes to a hollow arrow icon when you are within a feature's snapping tolerance. The 3D snapping will occur after you click in the 3D view.
Edit sketch feedback for subsequent vertices (for lines and polygons) will show the edit sketch in its snapped location, for streamlined editing.
Before you use classic snapping, you need to specify snapping settings. These settings include snapping tolerance, snapping properties, and snapping priority and are introduced below.
The snapping tolerance
The snapping tolerance is the distance within which the pointer or a feature is snapped to another location. If the element being snapped to—such as a vertex or edge—is within the distance you set, the pointer automatically snaps to the location.
You set the default snap tolerance value in map units or pixels on the Classic Snap Options dialog box from the 3D Editor menu (click 3D Editor, expand the Snapping side menu, then click Options).
Another useful trick for working with snapping is SnapTips, which is a message that is shown in the status bar for ArcGlobe and ArcScene. SnapTips identify the layer and the snap type (vertex, edge, end) to which your edit sketch is being snapped. Enable SnapTips from the Classic Snap Options dialog box accessed from 3D Editor > Options, the same place where you set the snapping tolerance.
The snapping properties
Setting layer snapping properties is simply enabling the snap type of the part of the feature (vertex, edge, or endpoint) to which you want your new feature to snap. For example, to make your new feature (a subway line) snap to the subway station point feature, check the box under Vertex next to subway lines in the Snapping Environment window.
The snapping priority
You can also set the snapping priority for layers in your 3D view. The order of layers listed in the Snapping Environment window determines the order in which snapping will occur. Snapping occurs first in the layer at the top of the list, then in each consecutive layer down the list. You can easily change the snapping priority by dragging the layer names to new locations.