Geometry Explorer Help
Using the Edit Menu: Animation of Points
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A very nice way to visualize certain geometric objects is to animate
their construction. Geometry Explorer has the capability of animating
points
along curvilinear objects (lines, rays, segments, arcs, and
circles).
There are four menu items in the animate group that control animation:
Animate Point:
To animate a point, it is required that the point be "attached" to
a curvilinear object. This is done by creating the point on top of the
object. After the attached point is created we can turn on an
animator
for the point by first selecting the point (at which time the menu item
"Animate Point" will be activated) and then choosing "Animate
Point"
from the Edit menu. Note: This only creates an animator for the
point,
it does not start the animation.
When animating a point on a linear object (line,ray,segment) the point
moves from the initial point created on the object toward the second
point
defining the linear object. For example, in the figure below segment AB
was created by first creating point A and then dragging to point B.
Point
C was then attached to the segment. If we now animate point C it will
move
toward point B at a constant rate.
When animating a point on a circle (or arc), the point will either
move clock-wise or counter-clockwise around the circle (arc) at a
constant
rate (equal to the rate of an animated point on a linear object).
After choosing the menu option "Animate Point" for a point on a circle,
arc, or linear object, a dialog box will pop up requesting which
direction of movement
is preferred:

When animating a point attached to an object that has a boundary
(segment,
ray, or arc). once the attached point reaches a boundary point the
animation
of that point stops. On the other hand, the animation of a point
on a line, ray, or circle will continue "forever" until you end the
animation
(menu option "End Animation").
Animate Off:
Use this option to remove the animator for a selected point. To
determine
if a point is being animated, use the info tool to get this information.
Start Animation/End Animation:
This option toggles between the two choices of starting or ending an
animation.
If there is no animation currently occurring the menu will read
"Start
Animation". Choosing this option will start up all animators that are
currently
defined. Animation is done by transforming points along
curvilinear
objects in such a way that all points travel the same distance in equal
time. Thus, if a point moves one unit along a segment in one animation
cycle, and a point is moving along a circle in the same cycle, then the
distance traveled by the point on the circle will also be one unit.
This
synchronization allows for the accurate prediction of the behavior of
multiple
animators. Look (here) for an
example of using animators to create cycloids.
If there is an animation currently occurring, then the menu will
read
"End Animation". Choosing this option will stop all currently defined
animators.
Clear All Animators:
This option will remove all currently defined animators.