# A helix formula!

1. Mar 10, 2005

### echoSwe

Hi!
I'm investigating whether you must use a logarithmic formula to describe a helix, or if it's enough to use two phase shifted sine curves... I've done a little excel document with a very siple implementation of two sine curves. One normal with the amplitude 23.8 and another one with the same amplitude as the first but phaseshifted such as: 23.9sin(1(x-90))+0. Where -90 is the phase shift.
My problem is that I can't plot it in 3d...
So the two are (degrees):
23.9sin(x) and
23.9sin(x-90).

I'd like to be able to rotate them such as you can do in e.g. Maya, to get a good feeling about how they look.

Does anyone know how to do this? I have Maya 6 PLE if that helps, which can do nurbs, and then if you find anything in C# or the .Net platform I also have the .Net framework to use, including DirectX 9.01 which can plot data. The only problem is that I don't know how.

The one criterea I have is that the angular twist is constant. Concider x,y,z on a paper lying on a desk. x, y are on the paper and z comming out from the paper, towards your face. The turn starts at (0, 1, 0) and finishes at (1, 0, 190) in meters. The angular turn per meter is constant. The formulas above are my first thoughts, and I would need to have a frequency of 90/190 = 0.47 in order to extend 1/4 cycle to 190 meters (the x axis on the graph).

Do you all understand? Hope so.

//Henke

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