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VTube-LASER uses surface points scanned with laser or measured with ball probes to calculate tube centerlines. Regular tube scans assume that the primitive shape to solve for is a cylinder.

When solving for a cylinder centerline, it's important to report the estimated accuracy of the calculation. The estimated accuracy helps us know how confident we can be in the calculation.

VTube-LASER reports the accuracy of the centerline fit in the Cylinder Fit Data window. The values are deviations for...

• RADIUS: Estimate the maximum deviation of half the diameter.
  
  
• X or Y POSITION: Estimate the deviation of the X or Y positions of the end points of the cylinder.
  
  

These estimate values are calculated using statistical math. The values are standard deviation x 2, which means that we have 95% assurance that the these values are the maximum deviation.

To simplify terminology, we say that the highest of the X and Y values is the "wobble deviation". If the centerline calculation is very good, then wobble deviation decreases. If the calculation or fit is poor, then the wobble deviation is too high.

VTube-LASER uses the wobble deviation to determine if it should ask you to remeasure the cylinder.

To allow VTube-LASER to warn for poor cylinder measurements, it stores tolerances for the allowed deviations during cylinder fit. These values are often setup in the Measure 1 tab of the System Options menu.

The default values are shown in the screen image on the right.

For less precise diameters like exhaust pipes, these settings usually work well. If you measure highly oval or deformed parts, it may be necessary to increase especially the X and Y Position tolerances.

Aerospace-grade materials are often very precise. For aerospace applications, we strongly recommend that you consider using tighter tolerances like these shown here.

The XY Positions should be 0.030" for longer straights, and 0.050" for shorter straights. ("Short" is also definable with the variable in the lower right corner. It is set to 2" length by default.)

Not all computers play these sound files the same way. For example some computer speakers go into an idle shutdown mode that can never start up fast enough to play the short sounds.

Before changing the sounds configuration, you can double click on any sound file, and Windows should play it for you. If you hear the sound when you double-click on it, then you should be able to use it in VTube-LASER for feedback.