Hi d3,

> when can we have option for creating spiral?

You can have it now! :)

For that, use the command under Draw curve > More > Helix:




There are various options within the command to control it - the default is to place 2 axis points and you will get a helix that is shaped like a cylinder.

If you want something that is spiraled like the shape of a cone instead of a cylinder, enable the "Tapered" checkbox option and that will let you pick a second radius for the end of the axis so that it is sloped.

If you want a completely flat 2D spiral, then push the "Flat spiral" button that shows up after the first point has been placed.

Some more description of it in the help file here:
http://moi3d.com/1.0/docs/moi_command_reference2.htm#helix

- Michael