This image shows how the "Twisted" lathe shapes are assembled
from several lathe segments.

This time I entered the 2D co-ordinates for the red lathe shape
(linear_spline) by hand into an array. The yellow spheres shows
where these points "travels" in 3D for each lathe segment.

The blue shape shows how similar things can by achieved with
cylinders. (I think there are some macros out there for doing
different kinds of cylinder "spaghetti".)

The cyan cylinders represents the axes that the different
segments are turned "around". (They are of coarse created at
origo and then tilted and translated to their final positions.)

The transition from one segment to another always happens in a
plane. And the rotation centres of both these segments also
have to lie in this plane.

At this moment my macro takes an array of such planes as an
argument together with the initial array of 2D points for the
lathe. It also needs a 3D reference point; ("Origo" for the 2D
co-ordinates) that "walks" from line to line (magenta spheres).

For every subsequent pair of planes in the array of planes it
calculates the lines I mentioned above. (These lines are the
intersections of each subsequent pair of planes.)

Currently I am investigating possible methods for gaining a
more intuitive control over the final shape.

There are several possible methods, but finding a good one is
not easy (for me). (And if everything else "fails", I may have
to use iterative numerical methods to help the users achieving
a path as close as possible to their "wish"-path.)


Tor Olav
--
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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