### Pointcloud/CAD Alignment Dialog Box Description

Pointcloud/CAD Alignment dialog box

ID: This displays the identification label for the alignment.

COP: This list lets you choose the cloud of points to use in the alignment.

Offset: This defines an offset value for a surface CAD model and is typically used with sheet metal parts. Applying an offset value essentially gives the surface CAD model a thickness so you can align the pointcloud data to a different face that isn't represented in the surface CAD model. For example, if you have a surface CAD model for the top of a part but you want to align to a corresponding bottom surface, you could apply an offset value of the part's thickness to align the scanned data it to the bottom side. Use a positive value if you want to apply a thickness in the same direction as the surface normal vector; use a negative value if you want to apply a thickness opposite the surface normal.

Auto: This area lets you automatically align the CAD with the cloud of points by using the Compute button.

Pointcloud/CAD Pairs: This area lets you create a rough alignment based on selected points from the CAD that correspond to selected points from the pointcloud. Once you have the needed pairs selected, you can use the Compute button to perform the rough alignment.

Refine Alignment: This area allows for a more refined alignment. It consists of the following items:

Total points: This box defines the number of random sampled points used to refine the alignment. This number must be a value of at least 3. A good number is around 200 points.

Maximum Iterations: This box defines the number of repetitions the process will make in order to refine the alignment.

Compute: This button begins the refined alignment process. A progress bar on the status bar shows the progress as the process moves through the alignment iterations.

Deviation: This area contains the following items:

Information boxes showing the Average, Maximum, and Standard deviations of the cloud of points in relation to the CAD model.

Histogram: This button takes a random sample of points from the point cloud, projects them onto the CAD, and then shows the deviations for that sample in the Pointcloud Alignment Histogram dialog box.

Sample Pointcloud Alignment Histogram dialog box

Matrix: This button displays the Pointcloud Alignment Matrices dialog box. This displays the numerical values of the alignment: the offset and the rotation matrix.

Pointcloud Alignment Matrices dialog box