Building the parenting chain
Video: Building the parenting chainMy next task is connecting together these individual layers in a way to make animation easier. For example, if I rotate this medium arm piece, I'd like this little arm piece to follow along with it. So I should probably parent the small arm to the medium arm. Likewise, if I move the big arm and rotate it, I would want these other smaller arm pieces to follow it. So at a minimum, I want the medium arm to be parented to the big arm. However, I would not parent the small arm directly to the big arm. I am going to leave it as a child to the medium arm.
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Parenting is a way to group multiple layers within the same composition inside After Effects. In this course, Chris Meyer shows how to set up a parenting chain, discusses what makes a good parent, and demonstrates several techniques using parenting, such as creating a title animation with a minimal number of keyframes, building a geometric construct, and bringing an anthropomorphic robot arm to life. Sidebar topics include avoiding a scaling gotcha with parenting and creating abstract backgrounds using the Fractal Noise effect.
The After Effects Apprentice videos on lynda.com were created by Trish and Chris Meyer and are designed to be used on their own and as a companion to their book After Effects Apprentice. We are honored to host these tutorials in the lynda.com Online Training Library®.
- Preparing files
- Making parenting connections
- Arranging the frame and arm
- Using null objects
- Crafting anthropomorphic-style animations
- Avoiding problems with non-uniform scaling
- Animating Fractal Noise
Building the parenting chain
My next task is connecting together these individual layers in a way to make animation easier. For example, if I rotate this medium arm piece, I'd like this little arm piece to follow along with it. So I should probably parent the small arm to the medium arm. Likewise, if I move the big arm and rotate it, I would want these other smaller arm pieces to follow it. So at a minimum, I want the medium arm to be parented to the big arm. However, I would not parent the small arm directly to the big arm. I am going to leave it as a child to the medium arm.
By creating a parenting hierarchy like this, moving one piece will move children of children, kind of like the leg bone is connected to the hipbone. It's the same thing is connecting together your own limbs and that's why it sometimes is referred to as an anthropomorphic type of animation. Finally, I like to have all the arm pieces connected to the frame, so if I pick it up to move it around, all the arm pieces go along with the rest of the mechanism. However, that's not all I need to think of. What's also very important is the anchor point for these individual pieces.
I need to carefully think about what center point I want these individual pieces to rotate our scale around. For example, I'll select the Small Arm and type R for Rotation. I'll scrub its Rotation and I really don't want that arm rotating around its center. That makes no sense. What I really want it to rotate around is this pivot point right in the middle of this circle. Likewise for the medium arm and the big arm. That requires carefully setting up the anchor point, and I highly recommend you do this before you make your parenting assignments.
If you do it afterwards, you have a chance that your positions and anchor point is not making as much sense. So I am going to zoom in to 200%, hold down the Spacebar to temporarily get the Hand tool, move it down, and I'm going to switch to the Pan Behind tool, which we sometimes also refer to as the Anchor Point tool. Y is the shortcut. I want that anchor point to be the middle of this circle. I'll pick it up and start dragging. I can just move it freely around and try to position it correctly or after I have clicked and started moving, I can add the Shift key to restrict my movement to just X or Y. If I feel that my anchor point is started out centered along this vertical line, I'll hold down the Shift key and drag it to what I think should be the center of that rotation.
Let's check it to be sure. I'll scrub Rotation and make sure that my arm stay centered in that pivot point and frankly, it looks pretty good. If necessary, I can nudge it, but that looks like it should work. I'll undo to get back to 0. It's really important to have a nice known stable starting position and I'll move down to the Medium Arm. I'll type R to reveal its Rotation, hold down the Spacebar, and drag to center the arm in my viewer, and again it pivots around its natural center point where the anchor point defaults at 2. I'll undo, start dragging, then hold the Shift key and drag this into what looks like it should be roughly the center point.
I'll scrub the Rotation and that's not too bad. It might be a little bit out around. So I might try to adjust it. I am moving it around a little bit here. See if that looks any better. Not really. So I just undo and get back to where I was and leave that as its anchor point. Again, note that I'm using the Pan Behind tool. This moves the anchor point and position at the same time so that I'm not moving the layer. I'm just moving the anchor point position's relationship. Pan down here to the big arm, select it, R for Rotation, with the Pan Behind tool start dragging anchor point, add the Shift key, and try to center it up and that looks really good.
Let's practice by rotating. A little bit out around. Let's see if we can make that any better by putting it down here. No, that's worse. I'll make one more shot at this, but I think my initial position might end up being the best. Nope! That's not around again, so I'll just undo, be happy with that, and I'll go back down to 100%, re-center. After I have set up my anchor points, I can return back to the normal Selection tool and now it's okay to parent.
So just as we said back in the Advanced Animation lesson, set up your anchor points before you animate. Same goes for parenting. Set up your anchor points before parenting. At this point it is just very simple. The small arm is connected to the medium arm, the medium arm is connected to the big arm, and the big arm is connected to the frame. That way if I move the big arm, everyone follows along. That's nice! Medium arm moves just the small arm, but not its parent large arm, and the little arm just moves all by itself.
So it all works out really nicely. So that's our parenting chain. Pretty simple to set up. But before we start animating it, we need to know what we're going to be animating it in relation to, what's going to be our timing, and what positions and space we want this arm to point out. Now to save your time we've already created a video edit for you. Go into your Sources folder and open up video edit. We've already spotted out important parts in the music. I'll zoom back a little bit here and cut video to go along with the music. We've also added composition markers that show where each video clip starts.
This will make it easier to set the timing later on, and I'm just going to drag this outside the Sources folder and close that back up again. What you still need to do, however, is place a few items of text around the screen to give you something to aim the robot arm at.
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