Three new primitives plugin for shell, spiral, gear

[oort]

PhilippePoupon,
Thanks for creating a shell plugin. Would it be possible to add a wall thickness option. The Intrude command makes it possible to hollow out the shell but with a very thin wall.

Also, would it be possible to add presets for various types of shells?

Here are a couple of programs that can produce sea shells for reference.

https://sourceforge.net/projects/whelk/

Documentation for Whelk

http://www.shelly.de/sl.html

Thanks,
oort