-
Using Sine to drive Opacity, but between a range of values
I basically have a shadow underneath a hovering object that I want to increase and decrease in opacity as a function of a sin wave. The hovering object already has this expression on it’s y position:
amp = 5;
freq = .75;y = amp*Math.sin(time*freq*Math.PI*2);
value + [0,y,0]The tricky part is, getting the max and min values to fall between something like 20 and 50. I understand it might be done with something like a clamp, but I don’t understand the syntax.
Thanks
-
3 Replies
-
This is probably the simplest:
freq = .75;
s = Math.sin(time*freq*Math.PI*2);
linear(s,-1,1,50,20)You might have to swap the 50 and the 20.
Dan
-
Brilliant.
Thanks Dan!
p.s. my colleagues and I are trying to figure out what the purpose of the Math*PI function is?
-
Math.PI*2 is the number of radians in one complete cycle of the sine wav. Including it lets the freq variable specify the frequency in complete cycles per second.
Dan
Reply to this Discussion! Login or Sign Up