Current Help System: PC-DMIS CMM (View Core Help)

### Working with Contact Sample Hits Properties

Probe Toolbox—Contact Sample Hits Properties tab

This tab becomes visible when you have the Auto Feature dialog box open and a contact probe is enabled.

The Contact Sample Hits Properties tab contains items that allow you to change the sample hits properties for a number of supported Auto Features that use contact probes.

Hint: A useful way of visualizing how these properties affect the measurement is to display pathways and hits by using the Show Hit Targets Toggle icon .

Depending on the type of feature in the Auto Feature dialog box, this tab may change to contain one or more of the following items:

Item | Supported Auto Features | Description
Sample Hits | Surface Point, Edge Point, Angle Point, Circle, Ellipse, Round Slot, Square Slot, Notch Slot, Polygon, Cylinder, Cone, Sphere | This list allows you to select the number of sample hits taken for the auto feature. These hits are used to measure the plane around the nominal point location, providing a sampling of the surrounding material. These are permanent sample hits.

For more information on sample hits, see "Sample Hits - Feature Specific Information" below.

Sample Hits Init | As Above | By default this list does not appear in the user interface because initial sample hits are used so infrequently. You can turn it back on using the PTPSupportsSampleHitsInit entry in the PC-DMIS Settings Editor. It allows you to specify initial sample hits. The Initial sample hits are taken only on the initial measurement of the feature during execution of the part program.
Spacer | Surface Point, Edge Point, Angle Point, Corner Point, Plane, Circle, Ellipse, Round Slot, Square Slot, Notch Slot, Polygon, Cylinder, Cone | This box defines the distance from the nominal point location that PC-DMIS will use to measure a plane if sample hits are specified. For more information, see "Spacer - Feature Specific Information" below.
Indent | Edge Point, Notch Slot | For an Edge Point, this box defines the minimum offset distance from the point location to the first sample hit. For a Notch Slot it defines the distance from the closed side of the notch (opposite the open edge). See "Indent - Feature Specific Information" below.
Indent 1 | Angle Point, Corner Point | This defines minimum offset distance from the feature's center location to the first of two or three sample hits. See "Indent - Feature Specific Information" below.
Indent 2 | Angle Point, Corner Point | This defines minimum offset distance from the feature's center location to the second of two or three sample hits. See "Indent - Feature Specific Information" below.
Indent 3 | Corner Point | This defines minimum offset distance from the feature's center location to the third of three sample hits. See "Indent - Feature Specific Information" below.

#### Sample Hits - Feature Specific Information

Auto Feature | Sample Hits Description
Surface Point | PC-DMIS will measure the point depending on the selected value. For example, if you select:

- 0, PC-DMIS will measure the point at the nominal approach vector specified.

- 3, PC-DMIS will measure a plane around the nominal point location and use the surface normal vector from the three hits measured to approach the nominal point location.

Edge Point | PC-DMIS will measure the point depending on the selected value. For example, if you select:

- 0, then PC-DMIS will measure the point at the nominal approach and normal vectors specified.

- 1, then PC-DMIS will measure a point on the normal surface. The edge measurement will then be projected into the nominal surface through this point. Any DEPTH = values will be offset from the point.

- 2, then PC-DMIS will take two sample hits on the edge along the nominal approach direction specified. PC-DMIS will then use these hits to calculate a new approach vector for the actual point measurement along the edge.

- 3, then PC-DMIS will measure the point with the combined methods of using one and two sample hits respectively. This measurement method is commonly known as a "Flush and Gap" measurement point.

- 4, then PC-DMIS will measure the three sample hits on the normal surface and adjust the surface normal vector. The edge measurement will then be projected into this new nominal surface. Any DEPTH = values will be offset from the point. Finally, the point will be measured along the approach vector.

- 5, then PC-DMIS will measure the point by taking three hits on the normal surface and two hits on the edge along the nominal approach direction specified. This method of measurement is considered the most accurate.

Various Sample Hits for Edge Points
A - Target hit B - Sample hits C - Indent D - Spacer E - Indent + Spacer

Angle Point | The sample hits will be used on each surface. PC-DMIS will measure the point depending on the selected value. For example, if you select:

- 2, the hits will be taken in a line perpendicular to the edge vector.

- 3, the hits will form a plane on each surface as indicated in the drawing.

Two and three Sample Hits for an Angle Point

Circle, Cylinder, or Cone | The defined sample hits will be used to measure the surface normal to the feature. The number of hits specified will be equally spaced between the starting and ending angle indicated. PC-DMIS will measure the point depending on the selected value:

- If Type = HOLE, and you select 0, PC-DMIS will not take any sample hits.

- If Type = STUD, you select 0, PC-DMIS will not take any sample hits. PC-DMIS then treats the Height value as if the feature were a HOLE instead of a STUD.

- If Type = HOLE, and you select 1, PC-DMIS will take the hit on the outside of the feature.

- If TYPE = STUD, and you select 1, PC-DMIS will measure the point on the top of the stud.

- If you select 3, PC-DMIS will measure the surface at three equally spaced hits starting from the starting angle. The sample hits will be relative to the measured plane, and any values will be offset from these points.

| A - Start Angle and End Angle

| A - Start Angle B - End Angle

Note: PC-DMIS expects the X, Y, Z nominal of the stud to be at the base. If the center point is at the top of the stud, set the depth and spacer to a negative value.

Sphere | For a sphere, you can only select one sample hit. When you select this sample hit, PC-DMIS follows this procedure once you execute the part program:

1. Automatic measurement stops prior to measuring the sphere.

2. PC-DMIS requests that you take one hit normal to the direction the sphere should be measured.

3. After you take the sample hit, click the Continue button

4. PC-DMIS then takes three more hits on the sphere in an area determined by the spacer.

PC-DMIS takes these four hits and uses the calculated sphere location to measure the sphere with the given number of hits, rows, and angles.

Square Slot or Round Slot | The measured plane will be used as the centerline vector for projection and measurement depth purposes. PC-DMIS will measure the slot depending on the entered value. For example, if you select:

- 0, PC-DMIS will measure the indicated slot. No sample hits will be taken.

- 1, PC-DMIS will measure the surface at the center of the slot. The slot hit will be to the right of the vector.

- 3, PC-DMIS will measure the surface at three equally spaced hits starting from SLOT A. The slot hits will be relative to the measured plane, and any values will be offset from these points.

Sample Hits of three hits on a Square Slot (on left) and Round Slot (on right)

Note: To take the hits on the opposite side of the slot, reverse the centerline vector.

Ellipse | The only values that will be accepted are zero, one, and three. The measured plane will be used as the centerline vector for projection and measurement depth purposes. PC-DMIS will measure the ellipse depending on the entered value. For example, if you selected:

- 0, PC-DMIS will measure the indicated ellipse. No sample hits will be taken.

- 1, PC-DMIS will take a single sample hit at the location where the ANGLE VEC points to (i.e. 0° + SPACER), not at the center of the ellipse (being particularly difficult should the ellipse be a hole).

- 3, PC-DMIS will measure the surface at points outside (or inside) the ellipse an indicated distance from the outer edge (Spacer value). The first hit will be at the indicated start angle. Hit number two will be halfway between the start angle and end angle. The last hit will be at the end angle. The hits will be relative to the measured plane, and any values will be offset from these points.

Note: To take the hit on the opposite side of the ellipse, reverse the centerline vector.

Notch Slot | The sample hits also define the edge for the angle vector and width. The only values that will be accepted are zero through five. The measured plane will be used as the centerline vector for projection and measurement depth purposes. PC-DMIS will measure the notch depending on the entered value. For example, if you selected:

- 0, PC-DMIS will measure the indicated notch. No sample hits will be taken.

- 1, PC-DMIS will measure the surface at the edge of the notch.

- 2, PC-DMIS will measure the edge along the open side of the notch. This will define the angle vector and will be used to find the width of the notch.

- 3, PC-DMIS will measure the surface at one end of the notch with two hits and one hit at the other end of the notch. The notch hits will be relative to the measured plane, any values will be offset from these points.

- 4, PC-DMIS will measure the surface the same as three sample hits. A fourth hit will be taken on the edge along the open side to be used in finding the width of the notch.

- 5, PC-DMIS will measure the surface the same as three sample hits. It will also measure the edge along the open side in the same manner as two sample hits.

Polygon | PC-DMIS will measure the polygon depending on the selected value. For example, if you select:

- 0, PC-DMIS will measure the indicated polygon. No sample hits will be taken.

- 1, PC-DMIS will take a single sample hit at the location to which the Angle vector points (i.e. 0° + SPACER).

Example Polygon Feature (hexagon) with one sample hit

- 3, PC-DMIS will take the three sample hits in a triangular position on the surface around the polygon, if an internal polygon or on the surface of the polygon itself, if an external polygon. The first hit will always be at the location to which the Angle vector points.

Example Polygon Feature (hexagon) with three sample hits

#### Spacer - Feature Specific Information

Auto Feature | Spacer Description
Surface Point | The Spacer box defines the radius of the circle on which the nominal (A) and the sample points (B) lie.
Edge Point | The Spacer box defines the radius of an imaginary circle on which the nominal and the sample points lie.

| A - Target Hit B - Sample Hits C - Spacer Distance

Angle Point | The Spacer box defines the offset distance between the points on each side of the bend.

| A - Indent B - Spacer C - Indent + Spacer

Corner point | The Spacer box defines the distance from the radius of the first hit to the other hits.

| A - Target Corner B - Spacer

Circle, Cylinder, or Cone | The Spacer box defines the distance from the circumference of the circle to the sample hits. Note: Clearance planes are not used when taking sample hits. When measuring studs, it is important to set the spacer value to a distance that will allow the probe to move around the stud.

| A - Sample Hits B - Spacer

Note: PC-DMIS expects the X, Y, Z nominal of the stud to be at the base. If the center point is at the top of the stud, set the depth and spacer to a negative value.

Square Slot, Round Slot, or Ellipse | The Spacer box defines the distance from the outer edge of the feature to the sample hit(s).

Spacer for a Square Slot or Notch (top) | A - Sample Hits B - Spacer
Spacer for a Round Slot

Plane | The Spacer box defines the distance between the hits making up the plane.
Notch Slot | The Spacer box defines the distance from the edges of the notch where the sample hits will be taken. Spacer (dotted lines) for a Notch Slot with two sample hits.
Polygon | The Spacer box defines the distance from the edges of the polygon where the sample hits will be taken. Spacer (dotted lines) for a Polygon with three sample hits (larger dots).

#### Indent - Feature Specific Information

Auto Feature | Indent Description
Edge Point | The Indent box displays the minimum offset distance from the point location to the first hit on each side of the bend (or edge).

Offset Distance from Edge | A - Target hit B - Sample hits C - Indent

Angle Point | PC-DMIS allows you to use two indent boxes, Indent 1 and Indent 2, in order to set the offset distances from the point location to the sample hits on each of the two surfaces of the bend in an angle point.

Indent in an Angle Point | A - Indent B - Spacer C - Indent + Spacer

- The Indent 1 box allows you to set the offset distance from the point location to the sample hits on the first surface of the bend.

- The Indent 2 box allows you to set the offset distance from the point location for the sample hits on the second surface of the bend.

Corner Point | PC-DMIS allows you to use three indent boxes, Indent 1 and Indent 2, and Indent 3 in order to set the offset distances from the point location to the sample hits on each of the three surfaces of the bend in a corner point.

- The Indent 1 box allows you to set the offset distance from the point location to the sample hits on the first of the three planes.

- The Indent 2 box allows you to set the offset distance from the point location to the sample hits on the second of the three planes.

- The Indent 3 box allows you to set the offset distance from the point location to the sample hits on the third of the three planes.

Indent for a Corner Point. For one of the surfaces, 1 shows the indent point, 2 and 3 are the sample hits | A - Target Corner B - Indent

Notch Slot | The Indent box defines where along the two parallel sides of the notch PC-DMIS will take the hits. It is the distance from the closed side of the notch, moving towards the open side. Indent for a Notch Slot (dotted lines) If you click on the CAD to automatically create the Notch Slot, PC-DMIS will automatically generate the indent value based on the size of your probe tip. You can later modify this if desired.

- If your tip radius multiplied by the NotchSafetyFactor is greater than the notch's width, PC-DMIS will display a warning message telling you your tip radius is too large.

- To generate correct measurement results, your probe's tip size multiplied by the NotchSafetyFactor should be less than the notch's width.