Multiple Objects Orbiting a Nucleus

[Peter Vyrostko]

There probably are different approaches to this..
For facing towards the camera……Transform>Auto – Orient>Orient Towards Camera….should work.
As for the animation..the following depends on how you have parented your objects.
For animating the centre…create a new adjustment layer called controller and apply effect Expression controller, rename it to offset.
This should serve as animated property for moving the planets off the centre.
Than, for offseting the position, aply to all the planets:
x=transform.position[0];
y=transform.position[1];
z=transform.position[2];
o=thisComp.layer(“controller”).effect(“offset”)(“Slider”);
[x,y,z+o]

This way you can animate all the z-offsets together, while you can also animate position of the planets separately.
You can use the same approach for offseting the anchor point, rotation or basically anything..
If you properly link all the properties to the propriate controller on an adjustment layer, you’ll end up with one layer with all and the only controllers you need to animate whole the composition and also the nested ones.
For even distribution I would create two keyframes with values of -1 and 1 and loop them over 2 fromes. Then I would multiply the value with the rotation or z-position.
As for stopping the animation at the certain point…
It depends on what do you actually animate and how…
As for animating the rotation of the planets I would probably use time information and multiply the value (on the adjustment layer) with the controller.
For stopping the animation at this case I would probably use another instance of the time,to deduct the value from the properties you animate over the time expression. To trigger this simple create trigger controller,which you animate from 0 to 1.
Then use this value wherever needed.
At this point this already seems confusing enough, so if you need further help with this solution I can help.
Depending on the number of the subjects I would probably stop all the animations manually.

Peter

x=transform.position[0];
y=transform.position[1];
z=transform.position[2];
o=thisComp.layer("controller").effect("offset")("Slider");
[x,y,z+o]

time*thisComp.layer("controller").effect("rotation multiplier")("Slider")

[Mark Lowe]

Wow, thanks for your help Peter! Very thorough.

I am off to try what you suggested and I wil let you know how I get on later.

Mark Lowe

[Peter Vyrostko]

well…good luck

after reading your post again…I realized, that the even distribution will not work that way. I used this approach with particles, so I got confused.

Also..if you want to move the planets in the direction off the centre, you’ll probably need a null object for each planet,and then animate the anchor point of the null object to move the planet off the main centre. .. you probably know this by now.

[Tim Boknecht]

I’m currently researching a way to do pretty much the same thing. Did this suggestion work for you? If not, can you tell us what worked for you?

Tim Boknecht
Media Producer
Bravo Productions

[Erik Justiniano]

Almost 4 years later…. YOU SAVED ME!’
Thanks! 🙂

[Mark Lowe]

Hi Tim

Crikey, I haven’t re-posted here for a while! Apologies for the very late response but, as Peter mentioned, his original expression didn’t work quite as he had hoped.

As my timescale was tight, I just did it the long-winded way. Basically, I divided however many objects I had in each orbit into 360 and then rotated them off axis by the appropriate amount (eg: 10 objects means the first at 36deg, the second at 72deg, etc).

So, it worked great but it was just fiddly and time-consuming. Note to self – must learn more about expressions…!

Hope that helps?

Best

Mark

Mark Lowe