Sketch With Snap Disabled
When Snap is disabled, the pointer will stay as a crosshair when Sketch is clicked. When you click the mouse, a point will be located whose XY coordinates are those of the crosshair and whose Z coordinate is the value of Depth on the Status menu.
This version of the Sketch mode relies entirely on using the mouse to pick locations, and is usually not used when precise locations are required, as in the creation of a commercial design. However, it can be useful when performing demonstrations and experiments or when learning SURFCAM.
Sketch With Snap Enabled
If Snap is enabled, the pointer will become a pencil when Sketch is clicked. When you click the mouse, a point will be located precisely if it is one of twelve specific types of Snap points.
A Snap point is an easily identified point on, or associated with, an existing line, arc or circle (but not a spline or a surface). Examples of Snap points are end points, midpoints, the foot of perpendiculars, points of intersection, centers of arcs and circles, and any point on a line, an arc, or a circle.
The precision of the Snap mode is due to the nature of the Snap function. If you click the mouse when the pencil pointer—or its projection—is within a predetermined distance from a Snap point, SURFCAM will select the Snap point rather than the actual location of the pointer, as in the previously described Sketch mode. SURFCAM is said to "snap to" the Snap point.
Note that because the projection of the pointer is used, the Z coordinate of the selected point is not affected by the value of Depth as it is with the other Sketch mode.
However, if you click the mouse when the pencil pointer—or its projection—is not within the predetermined "snap distance," the Snap-Sketch mode acts like the other Sketch mode in that the Z coordinate of the selected point will equal the value of the Depth parameter on the Status menu.