Datum identification for tolerances control on dense clouds of points

Optical Reverse Engineering systems are evermore used to check dimensional and shape conformity of manufactured components; their main advantage is the short acquisition time. Dedicated CAD software tools allow comparing the acquired data (clouds of points) with the 3D CAD model. Generally, they support the automatic global shape measurement; from the designer viewpoint this is not sufficient. The desired functional behavior of component is respected only when specific geometrical tolerances are verified. Our aim is the definition of methods to automate this last control process using Full of Information (FoI) CAD models. We define them as 3D model containing tolerance attributes and methods to check them. They allow comparing the toleranced features with the corresponding parts of point clouds. The present paper describes the approach and the developed method for datum identification usable for orientation and localization geometrical tolerances control. © 2008 CAD Solutions, LLC