To All,

A typical CMM application is the following:

Scenario:

A CMM operator is handed a part for inspection. The part is represented in CAD as (a) complex, non-prismatic, NURBS surfaces, or as (b) standard prismatic wireframe (lines and circles). The CAD entities are relative to a coordinate system that is usually "away" from the part (in body position). The operator is expected to report inspection results relative to body position.

The solution to this problem is to synchronize the coordinate system on the workpiece within the CMM machine coordinate system with the CAD coordinate system.

CMM software offer routines for iterative or complex alignments. The operator "joysticks" features off the workpiece and associates these to the features in CAD. Next a coordinate system transformation matrix is calculated that synchronizes the coordinate systems between the CMM and CAD. This calculation involves an interative procedure. Once established, there is usually an option to "re-iterate" to calculate a better fit.

I would like to learn about the techniques and steps used by CMM vendor softwares that perform iterative/complex alignments.

Any help in this area would be greatly appreciated.

Sincerely,

Mike Roterdam