#### Setting Probe Depth on a Sphere

PC-DMIS offers two procedures that allow you to set the probe depth on a sphere. Depending where the probe is located in relation to the centerline of the drawing determines where the hit will be taken on the sphere. If the probe is below the centerline, PC-DMIS will take the hit on the bottom of the sphere. To take a hit on the top of the sphere, the probe depth must be set above the centerline. See "Measuring Features Off-line" for additional information on the following procedures.

Three-Dimensional Procedure

To set the precise depth on a three-dimensional spherical surface:

1. Move the animated probe to the desired circle.

2. Hold down the right mouse button.

3. Release the mouse button. The precise depth will be set on the sphere.

PC-DMIS will position the probe on the side of the feature where the mouse button was first held. This determines the type of feature that will be measured. If the probe snaps to the outside of a circular CAD element, the hits will be placed outside the circle. If the probe snaps to the inside of the same element, the hits will be placed inside the circle. The circle’s three-dimensional origin must be the same location as the sphere’s center.

Once the precise depth has been set, all the points that are generated will snap on to the spherical surface.

Two-Dimensional Procedure

When using a two-dimensional drawing, PC-DMIS requires at least two views of the sphere. The sphere should be visible as a circle (or arc) in both views.

1. Set the precise depth for two of the axes using one of the views. (See "Setting Probe Depth on a Feature" for setting precise depth.) PC-DMIS will display the message: “Precise Depth Set on."

2. Using the second view, set the precise depth for the third axis. PC-DMIS displays the message: “Precise Depth set on Sphere.” This procedure finds the true three-dimensional center point of the sphere.

Once the precise depth has been set, all the points that are generated will snap on to the spherical surface.