2 Replies Latest reply on Feb 22, 2013 1:27 PM by Steve Eckhardt

    Equation Driven Curve Cannot Be Generated

    Steve Eckhardt

      I'm trying to create my first equation generate curve.  It is a compound parabolic concentrator.  Here's a picture with the equations and variables:

      EquationDrivenCurve.PNG

      In the yellow box you can see the error message.  I do not understand why the curve exceeds the maximum model size.  Here's a screen capture from Mathcad that shows the dimensions:

      CPC.PNG

      I really don't see why an object 4.346 mm long and 2*2.546 mm in diameter is too big for SW.  Any ideas?

        • Re: Equation Driven Curve Cannot Be Generated
          Jerry Steiger

          Steve,

           

          I didn't look at your equations, but if the radius of curvature of your curve gets larger than 500 m, then that could probably result in your error message. That would put the center of the radius more than 500 m from the origin, which is a no-no for SW.

           

          Jerry S.

            • Re: Equation Driven Curve Cannot Be Generated
              Steve Eckhardt

              Thanks for the response Jerry.  The isn't a single radius of curvature because the curve isn't a circle.  In the sense of analytical geometry, yes, the local radius of curvature (the inverse of the second derivative) might get rather large, but I haven't calculated it.  From what I read in the book "SolidWorks 2011 Parts Bible", it looks as if the curve will be approximated by a spline, so I can't see why the local radius of curvature would matter.

               

              I just discovered that SW2013 does conics.  Now if I can just figure out how to get from eccentricity to rho, I'll be all set.