gbAnimator - Links|
A link is simply the connection between two nodes. A link normally acts like
whose spring constant (stiffness) can be adjusted.
In addition a link can act as an Animator - a source of movement for the
model. An animator can generate a push/pull force on the nodes attached
to it - the equivalent to increasing or decreasing the length of the link.
Links in gbAnimator have properties which may be set by the user:
1. Animator - a flag to tell gbAnimator to use the animator force and
phase angle assigned to the link (see below). These two properties
are ignored unless the animator flag is set.
2. Spring Constant (k) - stiffness of the link
3. Angle - the timing used to apply the animator force. The push/pull force
of an animator is synchronized with the value of a sine wave applied to the
elapsed time of the animation. That's a complicated way of simply saying
that the force goes up and down - from a positive value (push) to a negative
The time at which an animator starts its push/pull cycle can be adjusted
by setting the angle (sometimes called the phase angle) property, with
values from 0 to 360 degress. Animation of an entire model can be created
by including several animator links in a model and adjusting the timing
(angle) of the links.
4. Animator Force - all of gbAnimator's animation tools work by applying
forces to masses. In the case of the link animator force, the property
is a value from zero to one, which corresponds roughly to an effect of
lengthening/shortening the link by the same percentage.
5. Barrier - a flag to tell gbAnimator to enable collisions between nodes and the link (still
Nodes also have display properties - highlighted, selected and animated.
A normal link, which is not selected or highlighted or animated is display
as a black line.
When a mouse moves over the mid-point of a link, a white dot is displayed and
the link is said to be highlighted. When the mouse moves off the link, the white dot
will disappear, leaving behind just the normal black line.
Once a link is selected the white dot is replaced by a blue dot and the link color
is changed to blue. To unselect a link, right-mouse click in an open area of the display.
To select a link you must click the mouse over the link mid-point.
To unselect a link, use a right mouse click.
As a convenience to identifying links whose animator flag is set, the toolbar
button "Highlight Animated Links" may be used to display all animated links
with a thick line.
The animator property of a link can be turned on by double-clicking on the mid-point
of the link, or by using the toolbar button "Animation Enabled".