Thursday, December 4, 2014

Helix Again

I've already posted about helix years ago. One of the readers asked me a question.
"How to make one way helix with pattern method?"

Yes. I've explained the way only for double helix at the last post.

Revit always makes two side faces when it creates a cylinder as above. So you need another formula to make one way helix.

Here is a picture to get the formulas.

You can get a formula for ANGLE as below.

tan(ANGLE)= (HEIGHT/(GRID*2)) / (pi()*RADIUS)
ANGLE = atan((HEIGHT/(GRID*2)) / (pi()*RADIUS))

And you can get offset distance as below.

sin(ANGLE)=OFFSET /  (pi()*RADIUS)
OFFSET = sin(ANGLE) *  (pi()*RADIUS)

Everything's done. That easy, huh?

Now you can get a helix pattern instantly with it.

And you can get any spiral shape with nesting another families in it.

Enjoy. :)

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