If you need to constrain an Arc based on a known arc length you have two ways:

 

Constrain arc length based on Chord Length (calculated) and Radius (known value)

    Or

Constrain arc length based on Angle (calculated) and Radius (known value)

 

Formula to calculate Angle=(180/PI)*ArcLength/radius

 

Formula to calculate Chord=2*radius*sin(angle/2)


The linked file below uses a known Arc Length as an example and has been created in TopSolid'Wood 2017 v6.18


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