How to read a color map 

 

 

General overview of a color map:

 A color map is a simple and effective way to interpret variation between two parts.  In most cases these parts include a CAD model as the nominal reference and a scanned part.  The scanned part is made up of thousands to millions of inspected points.  Alignment is made between the scanned and reference part.  Each point is assigned a color which denotes a certain deviation range.

 How alignment is created between scanned part and nominal reference:

 Proper alignment of scanned part and nominal reference is critical.  This usually happens one of two ways.  A “best fit” alignment is most common.  Algorithms analyze the point locations in the scan and apply and alignment to the reference part using feature recognition.  In some cases, datum structure can be applied to a reference model and fit to the scan.  The datums between the two parts are then aligned based on priority.

 The color map legend:

 After proper alignment is established, AcuSurf’s software analyzes the distance between each scanned point to its closest location to the reference surface.  Each point has a unique distance value from the reference.  A color map legend groups these points by color graduations.  The legend can have any number of graduations at any increment desired.

 In many cases AcuSurf will start a report with a simplified version of a color map known as a general variation color map.  These are utilized to give the viewer a rough idea of where variation is taking place.  It does not spell out whether points are positive or negative in relation to the CAD/reference model.  The following is an example of a general variation color map.

 

 

 

Once a general understanding of the scan is established, it’s important to know what side of the CAD/reference surface the scan points are on.  This is where an in-depth color map is employed.  The following is an example of and in-depth color map.

 

 

 

 

 

 

 

 

 

 

 

In-depth color map