Re: LOGO-L> Total Turtle Trip

[Chuck Shavit <CShavit@MagicSquare.com>]

At 07:32 PM 10/27/97 -0500, George Mills wrote:

>That's exactly what ARC does (actually ARC2)
>
>ARC2 :radius :degrees
>
>In fact I believe it was Yehuda that has ARCFD and ARCBK in his library
>or something like that. Note that ARC2 moves the turtle along the arc,
>ARC draws the circle about the turtle and does not move or turn the
>turtle.

Cool indeed.  I think Yehuda has what I had in mind, i.e., an extension of
FORWARD that goes the specified distance along an arc instead of in a
straight line.  I don't know what Yehuda implemented, but to be faithful to
the turtle geometry spirit (at least my understanding of it), ARCFD should,
in addition to moving the specified distance on the arc, also

  1. Leave the turtle facing tangent to the arc, so that a second ARCFD
     would continue the arc,

  2. Be consistant with the 3D environment, i.e. move along an arc 
     tangent to the 3D direction vector.

While (1) is relatively easy to implement and maybe was already
implemented, (2) might be harder.

Chuck Shavit

  
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