### Creating a "Perimeter Points" Feature

The Perimeter Points dialog box lets you create and edit Perimeter Points features in the inspection plan. This type of feature contains a collection of points defined on a section cut profile. The points are positioned on the section cut using an arc length. The arc length measures the distance along the section cut profile from a surface edge. When imported into PC-DMIS, these points are converted into vector points.

Perimeter Points dialog box

Similar to section cuts, this dialog box lets you specify a cut plane that intersects with the CAD model. Along the intersection line, you can define where points are created. The Perimeter Points feature is then created from these points.

For example, consider this sample Perimeter Points feature:

A Sample Perimeter Points Feature in the Graphics Display window | A - The green polyline in this screen capture indicates the cut plane's location. It goes completely around the part. B - The green arrows are perimeter points selected by clicking on the polyline. A red arrow indicates that the point is currently selected from the list of perimeter points.

C - The blue arrow that points out of the cut plane indicates the cut plane's vector.

D - A blue point appears when you select a single point from the list of points. It indicates the surface edge that the selected point is being measured from.

This may also display as a cross-hairs, depending on the DrawPointsAsSpheres registry entry located in the OpenGLSettings section of the PC-DMIS Settings Editor.

Creating a Perimeter Points Feature:

1. Define where the plane cuts the cad model.

- Ensure that the Select plane point option is selected.

- Click on the part model where you want the plane to be, or, if you want more control, type the exact point location in the XYZ boxes in the Point area. You can also use the snap option buttons to snap to the nearest 3D grid line or on the nearest surface edge.

2. Once you define the plane's location, a colored outline of the plane as it cuts through the CAD model appears (see A in the above image). Multiple colors sometimes appear along this cut plane make to make it easier to distinguish between multiple section cut profiles on the plane.

3. Choose the cut plane's direction by selecting or defining its vector. The colored cut plane outline changes to match the defined direction. The blue arrow pointing out from the cut plane shows its direction (See C in the above image).

- Use the Plane vector area to have the direction match one of the major axes (XYZ axis option buttons), an axis that matches the edge closest to the plane point (Edge), or a custom vector based on mouse clicks (Select... button), or a typed in vector (Other).

3. If desired, define the plane's rotation. You can use the Plane rotation area to define an angle and a vector about which to rotate. The colored cut plane outline changes to match the defined rotation.

4. Add perimeter points.

- First, click the Select perimeter points option button. This tells Planner to interpret mouse clicks on the section cut profile to define perimeter points instead of defining the plane point.

- Next, along the colored polyline for the cut plane, click on the line with the mouse. Planner will display a green arrow on the cut plane's polyline indicating the perimeter point's location and vector (see B above). The point is added to the Perimeter Points dialog box. If you try to create a perimeter point at the exact location for one that already exists in the list, Planner will simply highlight the existing point from the list. This helps you prevent creating duplicating points. This is especially useful when creating points with an arc length.

- Continue clicking until you have the points you want.

Note: Be careful about modifying the plane's vector or rotation after you've added points; doing so, even after you've created the feature, will potentially delete some or all of the points. After the plane parameters are modified, a point will remain only if it lies on the same surface. All other points will be deleted.

3. Adjust perimeters points using the Perimeter Points list. To work with multiple points at once, you can either hold down the SHIFT key while clicking within the list to select a contiguous range of points. Or you can hold down the CTRL key to select multiple points that are not in a contiguous range. Selected points will be highlighted in red in the Graphics Display window (see B above).

- To move a point to a new location, click on the point in the list and then click at a different location on the cut plane polyline. To deselect the point after moving it, hold down CTRL and select it again from the list.

- To delete one or more points, select the point or points, right-click on the list, and choose Delete.

- To flip the vector for one or more points, select the point or points, right-click on the point list, and choose Flip Vector.

3. Click Create. Planner inserts the feature into the Plan list as a with a "PPT" prefix.

Dialog Box Options

Item | Description
Select plane point option | This option is the first of two perimeter point selection modes that determine what happens when you click on the CAD model. This tells Planner to create a point on the CAD model which will become the cut plane point. The plane point's rotation and vector are controlled by the options in the Plane selection area.
Select perimeter points option | This option is the second of two perimeter point selection modes that determine what happens when you click on the CAD model. This tells Planner to create or edit perimeter points where you click along the cut plane's polyline (or section cut profile). If a single point is selected in the point list, then selecting a point on the section cut profile will update the selected point. Otherwise, selecting on the section cut profile will create a new point at the end of the list.
Use Arc Length check box | If marked, and you are selecting perimeter points, Planner will create points along the cut plane's polyline at the defined distance from the nearest surface edge. The surface edge used is the one closest to the location clicked on the CAD model.
Snap to edge and Snap to grid | Snap to edge - This check box determines whether or not Planner snaps the plane point to the nearest surface edge or surface boundary. Snap to grid - This check box determines whether or not Planner snaps the plane point to the nearest grid intersection. You can use the snap to grid functionality even when the 3D grid is not showing. See the "Setting up the View" topic to enable the 3D Grid.

If you select both Snap to edge and Snap to grid, Planner will snap the point to the nearest grid line that intersects a surface edge or boundary.

Plane vector area | This area allows the user to specify the plane vector. This can be one of the axes, the tangent vector of the nearest surface edge to the plane point, or a user-defined vector. X axis - This option sets the cut plane normal to the X axis vector (1,0,0).

Y axis - This option sets the cut plane normal to the Y axis vector (0,1,0).

Z axis - This option sets the cut plane normal to the Z axis vector (0,0,1).

Edge - This option sets the cut plane normal to the nearest surface boundary tangent vector. Whenever you select the plane point, the plane normal will be updated to the nearest surface boundary tangent vector.

Other - This option lets you define the cut plane normal values manually. Once selected, you can type the IJK values in the Plane Vector area.

Select - This option displays a Select Points dialog box that lets you select geometry in the graphics window to define the cut plane's vector. The selected geometry can be two points or a linear edge. This dialog box is already documented in the "Transforming a CAD Model" topic.

Plane rotation area | This area lets you rotate the plane vector about the specified rotation axis by a specified angle (in degrees). The rotation axis can be one of the axes or the surface normal at the plane point. Angle - You can specify any angle value from -180 to 180.

X,Y, or Z axis - Rotates the plane about the specified axis by the defined angle.

Surface Normal - Rotates the plane about the plane point's surface normal vector by the defined angle.

Point area | This area shows the XYZ values of the plane point. You can manually modify the values by typing new values in the X, Y, and Z boxes. Note that if the point you specify does not lie on a CAD surface, the actual point that is used will be projected onto the CAD model.
Vector area | This area shows the IJK values of the plane normal vector. You can manually modify these values by clicking Other and typing new values in the I, J, and K boxes.
Perimeter Points List | This list shows all the points added to the Perimeter Points feature. The columns display its ID, location (XYZ columns), vector (IJK columns) and the Arc Length. The arc length is the distance from the surface edge that the point is being measured from. This distance is measured along the section cut profile. You can use this list to work with existing points.

You can edit the ID and Arc Length values. To do this, click once to select a point. Click again on either that point's ID or Arc Length values. Type a new value.

You can use SHIFT and CTRL keys to work with multiple points. Once you have selected points, right-click on the selection and a small popup menu appears with these options:

Flip Vector - This flips the vector of all the selected points.

Delete - This deletes all of the selected points.

Create (or OK) button | The Create button creates the Perimeter Points feature and adds it to the Plan. The dialog box remains open after clicking Create, allowing you to create multiple Perimeter Points features. If you are editing an existing Perimeter Points feature, this button changes its text to read OK. Clicking OK applies changes made to the feature and closes the dialog box.
Close (or Cancel) button | This button closes the Section Cut dialog box. If you are editing an existing Perimeter Points feature, this button changes its text to read Cancel. Clicking Cancel closes the dialog box discarding any changes made.