Geometry Trigger mode allows you to define planar, cylindrical, or spherical cross sections that, when crossed by the probe, trigger measurement. By default, these geometric triggers are not defined. You first need to define them by right-clicking on the Geometry Trigger button, which will take you to the Make Geometry Crossing Triggers dialog. The top of this dialog (separated into Add Planes, Add Cylinders, and Add Spheres sections) is where the geometry triggers are defined. The active geometry triggers are displayed in the list in the center of this dialog.
Cartesian. Creates planar triggers (Figure 4-24) along the X, Y, and / or Z axes. After clicking this button, you are presented with the Cartesian Along Working Axes dialog.
In this dialog, check the axes along which you’d like to create planes, and also specify their start and stop position (in active units), as well as their spacing. In this example, planes will be placed along the active Z axis, from Z=0” to Z=20”, spaced by 2” (see image above).
It is important to realize that, due to a number of limiting factors such as hardware sampling speed and computer speed, the sampled data will almost never be taken exactly on the geometry’s boundary. In the Cross Sampling section, choose Interpolate to have SA interpolate between two sampled points on each side of the geometry trigger, and Closest Pt. to have SA use the closest sampled point to the trigger. The Interpolate option will result in a point lying directly on the geometry trigger (although it will not have been an actual sampled point), whereas Closest Pt. will be a true sampled point, but will likely not lie directly on the defined trigger.
You can also specify the width and height of the planes (for drawing purposes only) if they are going to be drawn in the graphical view.
Cylindric. Creates planar triggers that pivot about the working frame’s Z axis. Clicking this option brings up the Cylindric About Z in Working dialog. Here, you can define the start angle, stop angle, and angular spacing of the planes. Note that the X-axis defines the 0-degree plane for these values.
It is important to realize that, due to a number of limiting factors such as hardware sampling speed and computer speed, the sampled data will almost never be taken exactly on the geometry’s boundary. In the Cross-Sampling section, choose Interpolate to have SA interpolate between two sampled points on each side of the geometry trigger, and Closest Pt. to have SA use the closest sampled point to the trigger. The Interpolate option will result in a point lying directly on the geometry trigger (although it will not have been an actual sampled point), whereas Closest Pt. will be a true sampled point, but will likely not lie directly on the defined trigger.
You can also specify the radius (width) and length of the planes (for drawing purposes only) if they are going to be drawn in the graphical view. The settings in were used to create the trigger planes.
Select. Allows you to add an existing plane to the list of triggers by clicking in the treebar or the graphical view.
Cross-Sampling. This applies to triggers added via the Select method (see previous). It is important to realize that, due to a number of limiting factors such as hardware sampling speed and computer speed, the sampled data will almost never be taken exactly on the geometry’s boundary. Choose Interpolate to have SA interpolate between two sampled points on each side of the geometry trigger, and Closest Pt. to have SA use the closest sampled point to the trigger. The Interpolate option will result in a point lying directly on the geometry trigger (although it will not be an actual sampled point), whereas Closest Pt. will be a true sampled point, but will likely not lie directly on the defined trigger. Note that the desired option must be chosen prior to selecting the plane.
Draw In SA. This option will physically create the trigger planes in the job upon clicking the OK button for the Make Geometry Crossing Triggers dialog.
This section is used to add cylindrical geometry triggers.
Select. Allows you to add an existing cylinder to the list of triggers by clicking in the treebar or the graphical view.
Cross-Sampling. It is important to realize that, due to a number of limiting factors such as hardware sampling speed and computer speed, the sampled data will almost never be taken exactly on the geometry’s boundary. Choose Interpolate to have SA interpolate between two sampled points on each side of the geometry trigger, and Closest Pt. to have SA use the closest sampled point to the trigger. The Interpolate option will result in a point lying directly on the geometry trigger (although it will not be an actual sampled point), whereas Closest Pt. will be a true sampled point, but will likely not lie directly on the defined trigger. Note that the desired option must be chosen prior to selecting the cylinder.
This section is used to add spherical geometry triggers.
Select. Allows you to add an existing sphere to the list of triggers by clicking in the treebar or the graphical view.
Cross-Sampling. It is important to realize that, due to a number of limiting factors such as hardware sampling speed and computer speed, the sampled data will almost never be taken exactly on the geometry’s boundary. Choose Interpolate to have SA interpolate between two sampled points on each side of the geometry trigger, and Closest Pt. to have SA use the closest sampled point to the trigger. The Interpolate option will result in a point lying directly on the geometry trigger (although it will not be an actual sampled point), whereas Closest Pt. will be a true sampled point, but will likely not lie directly on the defined trigger. Note that the desired option must be chosen prior to selecting the sphere.
The Make Geometry Crossing Triggers dialog displays a list of the currently active triggers. You can single or multi-select active triggers, then remove them from the trigger list using the Delete Selected button. Or, you can delete all active triggers using the Delete ALL button.
Group Separately (Append Trigger Name). When this option is checked, measured points will be separated into point groups based on their respective triggers. The trigger name will be appended to the end of the group name as appropriate. Once the geometry triggers have been defined, click OK to return to the interface. At this point, left-clicking the Geometry Trigger button will take you into the measurement mode. Pressing the assigned Record button will begin (or continue) streaming points, and only those triggered by the geometry triggers will be recorded. To pause streaming, press the assigned Delete Last button. To exit measurement mode, press the assigned Accept or Cancel button.