"French horn" or "Sea shell" 3D solid

[wpeacock]

Using AutoCAD 2000

Anyone know how to produce a "French horn" or "Sea shell" 3D solid.

I need to draw a spiral with a circle at one end and extrude the circle along the path of the spiral whilst increasing the diameter of the circle.

The "normal" extrude command doesn't permit a taper angle when the path (polyline) is selected.

Kind of a similar problem to the "eccentric reducer" post earlier this year...

regards

Wayne

[scwegner]

These might help or at least get you started:

http://www.cadtutor.net/forum/viewtopic.php?t=240
http://www.cadtutor.net/forum/viewtopic.php?t=24&highlight=horn

[aledtaylor79401]

Sorry about the late reply, I’m new to this forum.

To approximate a French-horn / Sea-shell 3D solid:

Draw 2 arcs or polylines to represent the inside and the outside of the shape

Extrude circles of Diameter = largest diameter required along each of the arc paths

Apply the Boolean operation ‘intersection’

Radius the ridges with Radius = smallest radius required.

Aled Taylor
Design Engineer

(Just because something is not possible does not mean that it cannot be done).