To get everyone else caught up, I just finished the rigging course & Wayne told me that root bone is very useful when you want to shift the entire scene around. Follow up question, where is the best place to put the root bone in a scene? Do you place the root at the characters starting position, or do you just leave all the roots of every character at word origin?
I'm not much of a rigger or animator, but I think I know what you mean. For example first I thought you meant when rigging a character where do you place the root bone, but when you're modeling or rigging you're always at the center of the world, so the root bone is always at 0, 0, 0. You don't model or rig having things to the side of the scene, or up or below the grid in the scene, no, you model smack in the perfect center. So you place the root where it makes sense that it encompasses your whole model at the center.
But then I thought maybe you mean when you link a character to the scene that is going to be animated, for example maybe the character is going to jump off of a roof. So do you take the whole character even with the root bone to the roof, or do you leave the root bone at the world origin and you take the character with all the other controls to the roof.
So I would say, but don't trust me on it, I don't work much with animating or rigging, I would say you take the whole thing to the roof, to the starting position, with root bone and all and you start from there. It makes sense not having lots of root bones in the middle of the world origin. And if you want to offset the whole character a bit, then you move the root bone from that starting position. I hope that makes sense.
Simple answer - either.
It doesn't really matter where you leave the root, at the world origin or the starting position of the character, there is no right or wrong answer.
Keeping the armature and the root at the world origin helps if you want to adjust anything later, with the object origin and root at 0,0,0 it means it is still aligned with the world, and makes it simpler to make the adjustments.
Moving the root to the starting position is something Wayne does in the freehand animation of the Off-Road course. On the path animation the Root is left at the world origin and the Main has a follow path constraint which then moves the truck to the start position leaving the Root still at 0,0,0.
I think it is a personal preference really, and probably depends on the scene.
Having lots of root bones as Omar suggested at the world origin doesn't actually matter, because you will probably animate one character at a time, meaning there is only the root for the selected character in pose mode available. And also it would be unusual to move and animate the root.
I will say however, I would always leave the armature at 0,0,0 and move the root in pose mode if needed.
Excellent question Bryan.
The others have already given great responses, but I'll try to summerise and add some points.
Where do you place the root in the armature?
Always at 0,0,0 aligned with the world. This will make many things easier if it matches the world (trust me!)
Where do you place the root/armature object when you animate?
This one is more subjective. It might come down to the production, personal preference or the easiest spot to handle for that specific animation.
In my other job, we always start with the armature object (origin) at 0,0,0 and then we position the Root_GOD aligned with the world at the starting point of the animation in the scene (we also have 2 root controls). This is to make everything easier to problem solve if the animation gets out of whack with the scene.
But then there is still the "Root" to position. Where should that go?
Well that depends on the shot and/or personal preference.
Let's say your character is doing a some action like walking into frame, stopping, then turning about 90 degrees to face the camera.
Well you could start with the root off screen where he starts walking, use a walk cycle (where the root translates) all the way up to where he slows down, stop the root there and then animate the other controls moving away from the root at that point.
Each shot might be different though.
If you are animating the arcing ball bounce for example (with only 1 root). You would position the root on the ground where the ball starts, and then drag the body of the ball into the air and start from there. This is a logical place, but really the root could be anywhere.
In that example you would not need to animate the root at all - unless you need to tweak something.
I think I mentioned that the shot I was working on at the time (frog jumping across the screen) it was approved but the director wanted it a little closer to the camera. With the root control - I moved it where he wanted it and I was done. I did not have to touch any of the keyframes on the rest of the character.
Hope that makes sense.