Hi Keith,

> Even if I could achieve this goal it still isn't clear to me how
> I could chop the top off.

Well, if you can get a curve that is projected on to the outer surface of that shape, then you could delete the other surfaces and then trim the outer surface with the curve to slice off the top part, then use Shell on it to thicken that trimmed surface into a solid.

But it may be easier to try and construct a cutting surface.

You mentioned using rail revolve, but instead you may want to use Loft on a radial pattern of lines. For example here I used Transform > Array > Circular to duplicate a line in a radial pattern, then moved some of the lines up and then used Loft (with the closed option checked) to build a surface through them.

Once you have that surface created, you can then use it as the cutting object in Boolean difference to slice your solid into 2 pieces and delete the top part.













- Michael

Wow thanks
You are a helpful people. I'll give these suggestions a try.
Keith

Hi Keith;

This is another way;

-Draw a circle
-Add a point on the circle and use array circle to copy the points on the circle.
-Copy the circle and points in Z direction.
-Draw wave curve by connecting the points via freeform command (through points).
-extrude the first circle to make cylinder surface.
-use trim to cut the cylinder surface with wave curve.
-use the shell command to give a thickness to surface.


Sharif

Not this picture, but you did say Gears...There's a plugin that will do simple spur gears:

http://kyticka.webzdarma.cz/3d/moi/#SpurGear