Curve Calculator: Chord Definition

[schroederC3D]

Hi All,

I have a quesiton regarding the Curve Calculator tool, and the method by which it calculates the radii given a degree of curvature as input.

The method for calculating the degree of curve that I'm utilizing is:

The issue I'm having is that I seem to be getting different results between Excel and the Curve Calculator tool in Civil 3D.

Using Excel, I have the following formula and results:

 

And using the Curve Calculator, this is the result:

You'll notice, the radius given by the Curve Calculator above is consistently 1/2 of the the radius calculated using Excel.  Does anyone know the formulas used by the Curve Calculator?

[Mike.M.Carlson · Accepted solution]

Hello-

I think you have a slightly incorrect formula.  Civil 3D uses the following formula:

I hope this helps.

[schroederC3D]

Thanks Mike - I should have reviewed the formula rather than assuming it was correct.