ADOBE AFTER EFFECTS: Forum Expressions Tutorials Creative Cloud

# Rotating around a Null?

FAQ   •   VIEW ALL
 Rotating around a Null? on Feb 12, 2015 at 4:16:04 am

Hey guys! I'm new here, and I've got a bit of a dilemma.

My main goal is to Learn After Effects so I can add some shine to my Flash animations. For a starter project, I learned how to use the CC particle system, and got some pretty nice light streaks. I figured out how to attach them to Nulls and move them around using wiggle.

Now what I'm trying to do is get these Nulls to rotate around another Master Null. Problem is, when the Master Null rotates they just sit still. I've tried Parenting them, I've tried Pick wipping the rotation, Position, and anything else I could think of, but couldn't make it work.

I did some research into using paths, but I'm sure i'm missing something. Does anyone know of a tutorial that teaches how to do what I want?

 Re: Rotating around a Null?on Feb 12, 2015 at 2:04:00 pm

Open up your comp showing the master/child relationship and post a screen grab(third icon from the right).

Johnny Cuevas, Editor
Thinkck.com

"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.

 Re: Rotating around a Null?on Feb 13, 2015 at 2:57:53 am

 Re: Rotating around a Null?on Feb 13, 2015 at 12:53:44 pm

The nulls have been picked whipped to the position of the original null, that's going to place them at the original nulls position. So with parenting and that expression, they are just going to do exactly what the original null does.

Just make the nulls that control the emitters, childs of the master rotation null, move them to where they should go, then rotate the master null.

Johnny Cuevas, Editor
Thinkck.com

"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.

 Re: Rotating around a Null?on Feb 17, 2015 at 3:38:18 am

I still can't seem to get it to work. For some reason, when I assign them to the 'Master Null', they go to the far top left corner of the screen. Also, when rotating the 'Master Null', The child Nulls move, but the Emitters do not.
I've posted a video for you to see. Any Ideas?

 Re: Rotating around a Null?on Feb 20, 2015 at 12:58:20 pm

The emitters are being fed there position through an expression. When you make children of the nulls, the position is changes to the relative position between it and it's parent. That's the number that's being fed into to the emitters position. Since that relationship doesn't change when you rotate the master null, the child nulls will stay in the same position.

You might want to try posting this problem on the Expressions Forum, someone there might know of a way of using the absolute position so that your nulls will rotate.

Johnny Cuevas, Editor
Thinkck.com

"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.