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ptc-32427271-Visitor
1-Visitor
February 18, 2014
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Pspline or Cspline slope control

  • February 18, 2014
  • 1 reply
  • 2978 views

Hello,

Does anyone know how to control the slope (or end tangency) of a pspline or cspline curve? I'm using MathCad 15.

I want to input definition points (using x and z vectors) to create a spline equation z(x). The part I'm having problems with is trying to force the spline to have zero slope at the definition points. I've attached a sheet to help with the explanation. Any ideas?

In case this might help, I'm writing the sheet to evaluate a post-tensioned concrete beam with multiple spans. The function will be used throughout the sheet to define the tendons.

Best answer by AlanStevens

Attached shows a (slightly cheating!) way to do it.

spline.PNG

Alan

1 reply

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AlanStevens19-TanzaniteAnswer
19-Tanzanite
February 18, 2014

Attached shows a (slightly cheating!) way to do it.

spline.PNG

Alan

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    ptc-32427271-VisitorAuthor
    1-Visitor
    February 18, 2014

    Yeah, I think that does what I want! It is a bit of a cheat, but it seems as if MathCad doesn't have any built in functionality with the spline functions.

    I noticed that lspline (linear end points) pushes the curve closer to 0 slope at the definition points.

    Thanks for the help.

    Sean

    A
    AndyWesterman12-Amethyst
    12-Amethyst
    February 18, 2014

    Alternate method using 'Find' - a little easier to modify inputs

    Regards

    Andy

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