Meditor 

extrusionenv tutorial

This tutorial shows how to extrude around current view axis and applies radial envelope function simultaneously, so extrusion and deformations are applied at same time.
Home address for source code of meditor is: http://mesheditor.sourceforge.net
Create a circle from first button on objects window and that looks like as:
mtutor00extrudee.png
Move center rightwards as indicated in next image, notice it used edit->vertex mode.

mtutor01extrudee.png
In select mode, move whole mesh rightwards as indicated in next image.
mtutor02extrudee.png
Change view to top view using 'd' key. This will enable y direction to be used as axis in extrusion around axis service. Next image is how it should look like.
mtutor03extrudee.png
Select poins of the circle. I used ALT+enter. That should look as next image.
mtutor04extrudee.png
I will use 64 divisions. One should notice, this _must_  be the same for theta and phi number of divisions. One could use different values but theta and phi should have same number of divisions to produce same result as this. If one pushes '7' to change number of theta divisions, the main window should look as next image.
mtutor05extrudee.png
If one pushes '8' key to change number of phi divisions, the main window should look as next image.
mtutor06extrudee.png
Now one changes the number of turns around phi. Actualy, this will put radial oscilations on circular motion in theta, so the composed envelope is circular and oscilating.
mtutor07extrudee.png
Now one calls the service on actions window. I indicated the button used in next image.
mtutor08extrudee.png
If all worked, result should look as next image.
mtutor09extrudee.png
Now select that unwanted point in edit->vertex mode to be deleted.
mtutor10extrudee.png
Use 'Delete' key in edit->vertex mode to delete that selected point.
mtutor11extrudee.png
I use to delete duplicated points because last and original first points of whole cycle are on same place, so I just push 'Backspace' key. I use ALT+F10 to see the final result as next image.
mtutor12extrudee.png
That is all folks!