>   Hello Folks

Hi there!

>   I am in need of help in solving a three part problem. Hopefully some
> patient soul out there will look upon this request as a challenge and
> not the nightmare I do!
>   First, how is an elliptical orbital path for an object created?
>   Secondly, how can the speed of the orbit and the shape of the path be
> graduated individually or interdependently over a set variable of time?
>   And finally, could an elliptical orbital path be intersected at any
> two points with a straight line and rotated on that axis?

Well, it depends on what you want to do and how you want to achieve it. If
you're merely wanting to translate an object along an elliptical path, well
then use the following:

#declare Elliptical_Position = vrotate(<1,0,0>,y*360*clock)*<1,1,.5>;

That'd give you a path on the y-plane, turning clockwise, and it'd be
"squished" on the z-axis, but main radius is 1 unit (from the <1,0,0> at the
beginning).

How would you change that gradually you ask? Either add something to the
initial <1,0,0>, e.g. enlargening it to <2,0,0> would double the size of the
ellipse. To further rotate the ellipse about some axis, just do this
#declare New_Position = vrotate(Elliptical_Position,z*360*clock);

This would move the object along an elliptical path, which itself rotates
about the z-axis. Different transformations can be applied as well, you just
need to understand what's going on and how to model it.

-- 
"Tim Nikias v2.0"
Homepage: <http://www.nolights.de>
Email: tim.nikias (@) nolights.de

Post a reply to this message