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

## Nominal Point Best Fit Alignment

To create a Nominal Point (N-Point) Best Fit Alignment:

1. Create or Import Nominal Point Data. See "Importing Nominal Data".

Note: If Nominal Data is being used for Leica Reflector offsets and supports, make sure probe compensation option command is turned off and inserted before the points in the part program.

Edit Window - Probe Compensation inserted before nominal points

2. Execute the part program by pressing CTRL-Q or by selecting the File | Execute menu item.

3. The Execution Mode Options dialog box is displayed and guides you through the remaining measurements. Points can be skipped if necessary. Once all measurements have been completed, the dialog box closes.

Execution Mode Options dialog box

4. Insert a BestFit alignment by selecting Alignments | Align Free from the Quick Start interface or by selecting the Insert | Alignment | New menu item. The Alignment Utilities dialog box is displayed.

Note: The Alignment Utilities dialog box provides the most flexible way to create alignments but requires some experience.

5. Click Best Fit.

6. Select all features that should be used in the BestFit alignment.

Best Fit Alignment dialog box - Selecting Features

7. Exclude nominals for axes of selected input features for which theoretical values are not known. This is done by selecting "NO" under the axis column that should be excluded. This is useful in cases where you only know the theoretical values for one or two of the axes rather than all three.

8. Make sure that the correct options are set. In this example a Least Squares 3D alignment is created. By default, 3 Dimensional Orientation is selected for trackers.

Alignment Options

9. Press OK to compute the best fit alignment and insert the command into the part program. Overall results of the transformation are displayed in the standard PC-DMIS Report. The report uses the Enhanced BFAnalysis activeX control plus a new label. This new control adds a grid of results of each input before and after the alignment as well as the axes that were used in the calculations.

Since the alignment command comes after the measured features in the part program, the measured points are still presented in the previous coordinate system. To get the contributing point deviations in the newly created active coordinate system, insert Location dimensions into the part program after the alignment command.