Is there a way to create linear spirals?

Take a look at http://www.adobeforums.com/webx/.59b87878/0
To make a tornado-like shape you have to start off with a curved funnel-shaped object with no fill or stroke. Revolve it 360° and then map the graphics onto it. Flat spirals are not a good way to start for this one :-)

Hi. I am trying to understand these messages but am a bit confused. I am trying to create a spiral that looks like a tornado... bigger on top and smaller on the bottom. Is there a simple tool inside Illustrator that I can create one with? Thank you for any help.

Very creative solutions, thanks!

I actually dug out Freehand but its Spiral tool wouldn't do more than 200 windings. Good for future reference but not so much for this project. What I ended up doing was stealing this Postscript code:

http://www.graphicdesignforum.com/forum/showpost.php?p=387813&postcount=7

And imported it into CS4 after tweaking the code in a text editor. I got about 500 windings before Illustrator reported running out of memory (Activity Monitor said I still had 6GB free). I was hoping for more, but 500 is quite a lot. I think this will do very nicely!

as Kurt mentioned earlier, the single circle/multiple line brush version is something that has been kicked around on the Illustrator Windows forums: that's where I first saw it.

The single line brush/multiple circle version is my variation of that technique. It has some advantages, some disadvantages.

the 3D version was just a thought. It is actually the most versatile by far if you want fun variations (think spiraling confetti, etc.) and the center is more correct, but it is sloppy in the straight-on view.

All of them break at least once per revolution. The two brush methods wouldn't be too horribly difficult to join if you wanted to do that.

I wonder whether Average:Both, Join:Smooth would do it, or whether it would distort the spiral too much. Reckon we'd better do some experimenting :-)

After expanding the appearance, you get one stroke for every concentric circle you started with. You then need to join the endpoints together to get a single path. I noticed that, the farther away you get from the center, the farther apart the endpoints are spaced, but it's very slight.

Jean,
This looks very nice. I haven't tried making a spiral like yours but what is the output like? Do you get a single stroke or is it outlined? If so, I suppose you could delete one edge of the outlined stroke, but it would be nice to know before I start experimenting.

That is a really clever solution, Jean.