-
Manipulating an expression’s timing
Hello,
I’m fairly new to expressions and have a problem I’m pretty certain there is a simple solution for.
I’m using Dan Edbert’s pendulum expression which works amazingly –
https://www.motionscript.com/expressions-lab-ae65/pendulum.html
I am applying the expression to the z axis of a piece of footage to simulate a swinging from a wire effect.
The expression starts at frame 0 by default, but I would like to be able to dictate when the expression starts and stops. For example if I want to start the expression at frame 300 and again at 350 in the same piece of footage, what control setup do I need?
I’m pretty sure I can use a slider control, but I’m stuck at how to construct the correct controls.
If someone has a simple solution I would be very grateful
Thanks
Richieveloc = 7;
amplitude = 80;
decay = .7;amplitude*Math.sin(veloc*time)/Math.exp(decay*time)
-
3 Replies
-
something like this would allow you to use layer markers to control the timing for the start of the ‘wobble’.
veloc = 7;
amplitude = 80;
decay = .7;n = 0;
if (marker.numKeys > 0)
n = marker.nearestKey(time).index;
if (marker.key(n).time > time) n--;if (n > 0)
t = time - marker.key(n).time;
else
t = 0;amplitude*Math.sin(veloc*t)/Math.exp(decay*t)
to control how long it wobbles, you’d need to adjust the veloc, amplitude and/or decay variables.Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
Here’s the same thing with a couple of syntax issues resolved:
veloc = 7;
amplitude = 80;
decay = .7;
n = 0;
if (marker.numKeys > 0){
n = marker.nearestKey(time).index;
if (marker.key(n).time > time) n--;
}if (n > 0)
t = time - marker.key(n).time
else t = 0;amplitude*Math.sin(veloc*t)/Math.exp(decay*t)
Dan
-
thanks dan…. sorry richard if there was any confusion.
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW
Reply to this Discussion! Login or Sign Up