[Rutger]

Kevin,

I really appreciate your efforts, sorry I could not respond earlier…

Anyway, I tried your new suggestions and I see a lot of improvement, although there seems to be a slight amount of spin when I play with the initial x or z-rotation for instance (certain settings are clearly better than others). But the rotation is much better now, and I think I can select it such that artifacts are barely visible.

Initially, I thought it still did not work, but that was because I had actually turned my Sphere layer into a 3D layer. Reason for this is that I want to create a number of shadows (from multiple spotlights around the table). What I am planning to do is create multiple invisible discs (one for each light) that only cast shadows. Each individual disk would face (orient towards) one light. All these discs would be parented to the sphere layer, so as the ball moves, the shadows move along. This way I hope to achieve 4 or 5 different shadows that clearly look like artificial lighting.

Anyway, thanks a lot for your help. I am not sure that it is the ‘true solution’ to the problem, but it seems that I can work with this.

Thanks again,

Rutger

[Rutger]

Hello Moldyboot,

I tried your suggestion, but unfortunately I still get weird skidding effects.

Now, what expression do you use for the x rotation of the CC sphere effect? or are you only using an expression for y-rotation? Since I am looking for a rotation in two directions simulatenously. Again, when the ball simply rolls horizontally or vertically everything is fine. As soon as I use angles, the rotation starts to behave unnaturally.

So, for example, using your animation, can you put a ball in the left top corner of the screen and have it roll naturally to the lower right corner of the screen (without rotating the comp obviously….), if so I would like to know, because that is what I am trying to accomplish.

Let me know and thanks for your help…

Rutger

[Rutger]

Dan,

A Top view for now is all I want, since in another animation I already did a “3D view” of a pool ball. This was obviously using the same expressions that you suggested to make Andrew Kramer’s Earth Tutorial look three-dimensional, which can be applied to any spherical object of course. Now, correct me if I am wrong, but once you apply your expressions to the rotation, you lose the ability to dictate the rotation of the object. For example can you spin around a sphere, while the sphere is rotating in opposing direction?

Anyway, for this animation, I am not interested in a fully 3D experience (unless it can be easily done). I have a top-down view of a number of billiard balls that need to hit one another and roll convincingly over the table. Since the balls have numbers on them any slipping or skidding is going to look fake.

What I am looking for is expression for the rotation of the ball based upon the position, this assumes of course that the ball is played without spin, no slipping etc. So if postion at the ball at time 0 = [x0,y0] and at time t = [xt,yt] what expressions can I write for rotation as a funtion of time in both x and y direction.

I was thinking myself along the line of comparing its current x and y coordinate to the respective values at time zero, and using this difference to steer the rotation, but I ran into errors when using valueAtTime command.

Any ideas are greatly appreciated.

Rutger

[Rutger]

Looks like you got the same answer twice. Did not see Andrews reply yet when I started typing.

Well, at least it works.

Rutger

[Rutger]

Staggering can be done by selecting the layers that you want to stagger. Then right-click and choose Keyframe assistant > Sequence Layers. Make sure that overlap is not checked and they should now line up nicely. I am not sure how to have layers move so that they automatically ‘snap’ to eachothers in or outpoints.

Hope it helps.

Rutger

[Rutger]

Just use the Numbers effect under Effect > Text > Numbers and set keyframes for the value.

Hope that helps,

Rutger

[Rutger]

Thanks for your suggestion. I was afraid that there would be no elegant way of doing it.

Rutger

[Rutger]

Quentin,

Instead of trying to copy and paste keyframes, I would suggest adding a simple expression to the Scale property. Simply use the pickwhip to link the Scale to the “Both Channels” slider on the Audio Amplitude layer that was created when you converted audio to Keyframes.

It will write the following code for you:

temp = thisComp.layer(“Audio Amplitude”).effect(“Both Channels”)(“Slider”);
[temp,temp]

Since Scale on a 2D layer has two dimensions (width and height), the audio amplitude ion the example determines both. To get variations on the theme, simply change the second line to for instance [temp, temp*temp] or [temp, temp*2]. This way the variations in height will be more dramatic than the variations in width. If you just use some basic math you should be able to get the effect you want.

For more powerful control of audio keyframes have a look at Soundkeys by Trapcode.

Hope that helps,

Rutger

[Rutger]

Thanks Dan,

It is working now, and I also was able to rename the sliders by using the

myLayer.effect(1).name = “Amplitude” command so that all the sliders are properly labeled and organized.

By the way, now that I have your attention, I read in the After Effects Scripting Guide that there is no method built in After Effects that can record a series of actions and convert them into script. Do you know of any 3rd party plugins that would do this? It would essentially be a ‘macro’ recorder, as you see for instance in Visual Basic for Excel. I think such tool could be very handy for more entry level users that want to take advantage of scripting. But it may simply not exist.

Thanks again,

Rutger

[Rutger]

Thanks Dan,

It is working now, and I also was able to rename the sliders by using the

myLayer.effect(1).name = “Amplitude” command so that all the sliders are properly labeled and organized.

By the way, now that I have your attention, I read in the After Effects Scripting Guide that there is no method built in After Effects that can record a series of actions and convert them into script. Do you know of any 3rd party plugins that would do this? It would essentially be a ‘macro’ recorder, as you see for instance in Visual Basic for Excel. I think such tool could be very handy for more entry level users that want to take advantage of scripting. But it may simply not exist.

Thanks again,

Rutger