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

### Creating a Pointcloud/CAD Alignment:

To create a Pointcloud to CAD alignment, do the following:

1. Ensure that you have an imported CAD model in the Graphics Display window and a COP command in the part program. These elements are required to align pointclouds to the CAD.

2. Select the
   Insert | Pointcloud | Alignment menu option. You can also access this dialog box by typing the COPALIGN command in the Edit window’s Command mode between the ALIGNMENT/START and the ALIGNMENT/END commands.

3. The dialog box appears:

Pointcloud/CAD Alignment dialog box

4. A temporary split screen view of the CAD model and the cloud of appoints appears in the Graphics Display window. You can use this CAD view to visually see the alignment taking place.

Split screen view showing the CAD model on the top view and the point cloud on the bottom view

5. If you have more than one pointcloud in your program, choose the cloud of points from the COP list.

6. Perform the alignment:

- - First, use the Pointcloud/CAD Pairs area to perform a rough alignment that will bring the pointcloud close enough to CAD (if not already close) to be able to refine the alignment further if needed. You should use this type of alignment if the pointcloud is not complete or it contains scanned data belonging to a fixture, the table, and so forth.

  - - Click a desired number of points on the point cloud.

    - Click corresponding locations on the CAD model.

      Split view showing selected cloud points and corresponding CAD points

    - The more points you take around the different areas of the model and point cloud will result in an improved alignment.

    - Click Compute to create the rough alignment.

  - Next, use the Refine Alignment area whenever you want to refine your alignment, thereby bringing the pointcloud closer to your CAD model. In order to be able to obtain a good refined alignment, the pointcloud points should be close enough to the CAD points through an initial rough alignment.

    A sample rough alignment that needs a refinement

  - - Define the total number of random sample points to use in each iteration in the Total Points.

    - Define the number of iterations in the Maximum Iterations box.

    - Click Compute to refine the alignment.

  - Alternately, you can use the Auto Area area to automatically create the alignment. You should only use this when you have a clean pointcloud (without outliers) and a full scan of the external faces of the part. Simply click Compute. This also performs a refinement on the alignment as it generates.

6. If a portion of the cloud doesn't align nicely with the CAD, you can click the Undo button and recompute using the same type of alignment with additional parameters, or you can try a different alignment.

7. If you want to align to a different face that you don't have in your cad model, you can define an Offset value.

8. Use the Deviation area to determine how well the point cloud aligned with the CAD.

9. Once you're satisfied with the alignment, click Create. PC-DMIS closes the temporary split screen view and places the COPALIGN command in the Edit window. See the "COPALIGN Command Mode Text" topic.

Note: If needed, you can adjust the CadGridSizeForPointcloudCadAutoAlignment registry entry to define the distance between the grid of points used to align the pointcloud to the CAD model.