### Guessing a Measured Feature Type

The following table shows the minimum number of hits PC-DMIS needs to guess a particular Measured Feature and that feature's dimension type.

Minimum # of Hits | Feature | Dimension
1 | Point | 1D
2 | Line | 2D
3 | Circle | 2D
3 | Plane | 3D
6 | Cylinder | 3D
6 | Cone | 3D
4 | Sphere | 3D
7 | Torus | 3D

Measured Point - Rules:

- Probe compensation is in the nearest axis (X, Y, or Z). This is determined based on the direction of machine motion at the time the hit is taken. Always approach normal to the surface.

- Only measure points on surfaces perpendicular to the X, Y, or Z axis to ensure accurate probe compensation.
  Note: Use Vector or Surface points for other surfaces (Auto Feature).

- Measured Points are 1D, therefore dimensional information is only valid in one axis (X, Y, or Z).

Measured Line - Rules:

- Measured Lines are 2D, therefore they are dependent on the active workplane for calculation purposes. You must activate the appropriate workplane before measuring a line.

- You control the direction of the measured line. The direction will go from the first hit towards the second hit.

- The dimensional information in the X, Y, or Z axis is from the centroid of the line.

Measured Circle - Rules:

- Measured Circles are 2D, therefore they are dependent on the active workplane for calculation purposes. You must activate the appropriate workplane before measuring a circle.

- A minimum arc of 90 degrees is required to accurately calculate a measured circle.

- The dimensional information in the X, Y, or Z axis is from the centroid of the circle, and the diameter is the average diameter by default (least squares).

Measured Plane - Rules:

- Measured Planes are 3D, therefore they are not dependent on the active workplane for calculation purposes.

- The IJK vector for the plane is perpendicular to the plane, and its direction points away from the material of the part.

- The dimensional information in the X, Y, or Z axis is from the centroid of the plane.

Measured Cylinder - Rules:

- Measured Cylinders are 3D, therefore they are not dependent on the active workplane for calculation purposes.

- You control the direction of the IJK vector for the cylinder. It goes from the first circular cross-section towards the second circular cross-section.
  Note: You should take three circular cross-sections when possible to increase the hit data used to calculate the cylinder.

- The dimensional information in the X, Y, or Z axis is from the centroid of the cylinder, and the diameter is the average by default (least squares).

Measured Cone - Rules:

- Measured Cones are 3D therefore they are not dependent on the active workplane for calculation purposes.

- You do not control the direction of the IJK vector for the cone. The IJK vector always points away from the vertex of the cone. Note: It is recommended to take three circular cross-sections when possible to increase the hit data used to calculate the cone.

- The dimensional information in X,Y, or Z axis is from the centroid of the cone.

Measured Sphere - Rules:

- Measured Spheres are 3D, therefore they are not dependent on the active workplane for calculation purposes.

- In some cases it is not possible to take a hit on top of the sphere. In these cases take three circular cross-sections and the IJK vector direction will go from the first toward the last cross-section.

- The dimensional information in the X, Y, or Z axis is from the centroid of the sphere and the diameter is the average.

Measured Torus - Rules:

- Measured Tori are 3D, therefore they are not dependent on the active workplane for calculation purposes.

- The first three hits must be taken in a plane around the torus that is perpendicular to the center circle.

- The dimensional information in the X, Y, or Z axis is from the centroid of the torus.

Using Guess Mode

1. Access the Edit window, and place it in either Command or Summary mode.

2. Place PC-DMIS into Program mode
   , and set the appropriate probe depth.

3. Access the Measured Features toolbar, and then click the Guess Mode icon.

4. Click on the model of the part at the location where you want to insert the feature.

- If you're using an imported wire frame CAD model, PC-DMIS will automatically use the nearest wire as the basis for the feature you selected.

- If you're using an imported solid CAD model, each mouse click is counted as an individual hit.

5. Press the END key. PC-DMIS interprets your hits and places the guessed feature into the Edit window.

For information about the Guess Mode icon and the Measured Features toolbar, see the "Measured Features Toolbar" topic in the "Using Toolbars" section.