How to draw a 3D helicoid ?

[AVW]

Hello,

Does someone have a programming method (LISP or VBA) or a manual method to draw a 3D helicoid on which we may generate a profile ?
Thanks for help.

 

[pardal]

What is the formula of the helicoid?
The only profile youl could strude on a 3d Polyline is a circle.
You can draw any curve on 3d




Pardal

 

[RiBeneke]

You need to create a 3d polyline spiral and then extrude your shape along this path.
On Cadalog at

http://www.cadalog.com

you should be able to find 3DSPIRAL.LSP
or on Autodesk User Group International at

http://www.augi.com

in the exchange section you should be able to find HELIX.LSP
and these should help you.

 

[smcadman]

Depends on what profile you are wanting to use on your helical, and if you want a solid or a surface. So far, I have only found 1 routine that successfully extrudes a profile other than a circle along a helical path, with the end-product being a solid. It is written by Fuccaro at another Cad forum:

http://www.cadtutorforum.net/forum/viewtopic.php?t=74

You have to follow the directions carefully as to how to use it.
The problem with all other spiral routines is that they twist your profile as it is extruded along the path.
Here are some examples of Fucarro's helical exrusions.
Off topic-he has some interesting routines he wrote for a telephone cord and a shell that is worth checking out.

Flores