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Change floor position in Bounce expression
Darby Edelen and Dan Ebberts helped me cobble this expression together and now I need to modify it in the following way.
I need the ball to bounce ONCE on the floor then I need the floor to fall away. I have tried tying the floor to an expression slider and animating it at the point where I need the change to happen, but this affects the whole animation and just sends the ball hurtling downwards. I just need the floor to act as if it isn’t there on the second bounce.
Any help is much appreciated.
With many thanks,
DavidVy0 = 200; //initial y velocity (pixels/second)
seedRandom(index,true);
Vx0 =random(-200,200); // initial x velocity (pixels/second)
g = 2500; // gravity (pixels/second/second)
floor = 1050;
e = .82; //elasticityb = floor – position[1];
h = b + Vy0*Vy0/(2*g);
T = Vy0/g + Math.sqrt(2*h/g);if (time < T){ y = Vy0*time - g*time*time/2 + b; }else{ Vy = -(Vy0 - g*T); while (true){ Vy *= e; t = T; T += 2*Vy/g; if (time < T){ t = time - t; y = Vy*t - g*t*t/2; break; }else if (T - t < thisComp.frameDuration){ y = 0; break; } } } [position[0] + Vx0*time, floor - y]
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2 Replies
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Try this:
Vy0 = 200; //initial y velocity (pixels/second)
seedRandom(index,true);
Vx0 =random(-200,200); // initial x velocity (pixels/second)
g = 2500; // gravity (pixels/second/second)
floor = 1050;
e = .82; //elasticityb = floor – position[1];
h = b + Vy0*Vy0/(2*g);
T = Vy0/g + Math.sqrt(2*h/g);if (time < T){ y = Vy0*time - g*time*time/2 + b; }else{ Vy = -(Vy0 - g*T); Vy *= e; t = time - T; y = Vy*t - g*t*t/2; } [position[0] + Vx0*time, floor - y] Dan
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This looks great, thank you.
Now of course I need the balls to bounce twice not just once before the floor falls away.Help please!
Con Muchas Gracias!
David
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