Help with time expression!

Report · Jul 16, 2014

Hi everyone, I need some help with the time expression.

Im working with video copilot´s plugin element 3d and i've made a spere shaped thing with particles which im going to sync to music. The problem is that when i make the simple expression "time*321" on the noise evolution value to make the sphere move organicly throughout the whole video it only does so for about two minutes then it just stops changing even though the value changes. The pictures might help you understand.

Pictures: http://puu.sh/adNNB/e8de72a1e8.jpg, http://puu.sh/adNQJ/4fe8d4fe94.jpg, http://puu.sh/adNRx/8ecff2b2ca.jpg

Then there is another problem which is that the sphere evolves alot faster with the time set to 321 compared to when i have it on 30.

I hope you can help me and im sorry for my bad english just tell me if there is something you dont understand.

Report · Jul 18, 2014

I think you are giving the rotation value more than it can handle. After a while, many of the values in AE will stop increasing because the math can't go any further. Here are two things for you to try.

1) Use this simple expression for increasing the value of something.

THE BIG PICTURE: ([Amount of Change] / [Number of Seconds]) * time

ROTATION EXAMPLE: (360 / 5) * time; <----- This will rotate a layer 360º over 5 seconds. It will also continue to rotate until the end of the comp or you run out of math.

POSITION EXAMPLE: delta = (500 / 2) * time; // This changes the value of "delta" 500 units over 2 seconds and continues.

x = value[0] + delta; // Uses the x value from frame 0 and adds the delta to provide movement

y = value[1]; // Uses the y value

[x, y] // sends the values back to the layer

2) Modulus will recycle the numbers. Using your current expression, you can add modulus, and use it to recycle your math.

EXPRESSION: (time * 321) % 360

The % is the modulus, and it resets the count every 360º.

Good luck!

Trent