Rig Hierarchy - You Have Options

What should be the anatomy of your rig? Hierarchy is important because it serves two purposes. Certain decisions are made for the sake of organisation, other decisions have effects on function and performance. Some decisions can serve both purposes and could be argued to have a correct answer, but other times you can only serve one of these purposes at a time. And a decision will need to be made whether a little performance is worth sacrificing for better organisation, or vice versa.

Organisation doesn't necessarily just mean easier to look at and sort through. It could also be a matter of putting components of your rig in a place in the hierarchy which will accommodate scripts you know will be run on the rig in future.

If you know that your animators have a script they run to expose or hide all the joints, and you know that script works by finding the joints group and hiding/unhiding it then obviously there needs to be such a group and all the joints need to be within it.
If you wanted to reform that aspect of the hierarchy within a pipeline, they would need to change their script to identify the joints some other way.
So how you arrange your rig hierarchy is often about the needs of people further down the pipeline.

You might have heard people arguing online about the merits of broken or unbroken hierarchies. But this is misleading. All hierarchies are broken. It's a question of how much.
A rare example of a completely unbroken hierarchy is perhaps the driven skeleton that gets exported into videogame engines. But I don't know if that even counts as a "Rig" if there's nothing driving the skeleton.

How Maya Handles Node Names

 When you start to automate repetitive processes via script, it quickly becomes important how you manage object names within Maya. Up on the surface, where the human brain hangs out, we know nodes if not by their spatial position and appearance in the scene then by their names; what the objects are called, such as in the outliner. But that's for the user's benefit. Maya itself keeps track of objects by different names then the ones shown in the outliner.

I'll give you an example. If you have an object in the scene and then you duplicate it, Maya will automatically edit the name of that duplicate (adding a number on the end) so that it doesn't have the exact same name. Maya doesn't let two objects have the same name.

Important Math: Pi

 Let's talk about piiiii!

This post will explain what on earth Pi even is.
This guy:
π
It's the Greek letter 'pi', that's how it's pronounced. You might see it written as 'Pi' or as 'π' but it's the same thing. It's used in mathematics to talk about a very special number. A very special ratio. I can't overstate just how fundamental the number Pi is to mathematics. It shows up as the answer to so many problems in the natural world. It's freaky. Like there's logic to the fundamental structure to the universe. But not an order that could pick a more convenient number, because the magical number I'm talking about - the number that Pi refers to, is this number:

3.141592653589793238462643...

The reason it trails off like that is because it's what's called an irrational number. You don't gotta remember that, it's just a fancy way of saying it's a number whose decimal places go on forever without a pattern ever emerging. It's crazy, I know. Numbers are weird.

So Pi is usually talked about in terms of just its first two or three decimal places:

3.14

Reverse-Engineering Rigs

You should take any opportunity you can to learn from more experienced riggers. There are many character rigs available on places like Gumroad, Gumroad, and even Gumroad if you can believe that!

I learned a crap-tonne by pulling these rigs apart and learning how they accomplished certain effects. How there are multiple ways to do just about anything.
Reverse-engineering rigs is a super vital skill. Like, you need to know how to do it. Not just for learning from downloaded rigs, but when your own rigs bug out (and they will) you use the same reverse-engineering skills to isolate the problem before fixing it.

But there are many ways for riggers to hide their tracks, either intentionally or just as a side effect of keeping the rig clean for animators. Even if not, there some key places to look to find vital information quickly when understanding how a rig system works, and what might be going wrong when diagnosing problems.
Here are some tricks you should know about.

Inputs in the channel box

There Are More Math Nodes Than You Think

Maya has a looooot of utility nodes. I still occasionally find new ones that I wish I'd always known about.
Before we look at some of them, I just wanna point out something important: A lot of nodes in Maya when placed in the node editor appear to not have any inputs, or at least not the ones your looking for. A lot of attributes will only become exposed when you right click on the node and pick 'Show All Attributes'. I don't understand why they couldn't map this to the 4 key.

Oh yes. The 1 key hides everything, 2 shows the attributes that have connections, and 3 shows all attributes... except all the ones it doesn't.

Oh. Well can I expose those too?
Sure can!
I assume with the next key in that very clearly and deliberately established sequence?
nnnnnope : )

Transformation vs Deformation: The Two Pillars of Rigging

Food for thought:
What is rigging, exactly?

Perhaps it's simply making stuff move. But that could also be a description of the animator's job.
Making stuff able to move then, perhaps?
When I need to explain what I do to my grandparents... well I usually just tell them I'm an animator. I work at an animation studio, mine and the efforts of many others are to make animations, I'm an animator. Fuck it. That'll do.

But it really is about making stuff move.
And in Maya there are two kinds of motion. Transformation and deformation.
Every frame, Maya has to figure out where to draw the hundreds, thousands, potentially millions of points in 3d space that we call vertices. Whenever an object is either transforms or deformed, Maya has to run complex calculations to reevaluate the vertices of that object.

Transforming

Yet again, the technical term doesn't sound very accurate to what it describes.
Oh yeah! Transforming. That's that magic button the artists who worked on the Transformers movies pressed and then they all got to go home and be with their families and were not overworked at all! ...Right?