Utility Nodes: pointOnCurveInfo

This little work horse will be your new best friend!

The pointOnCurveInfo node.

This node allows you to pin a transform node anywhere on a nurbs curve, and the applications there are numerous.

Aside from the usual parametres that almost all utility nodes have, pointOnCurveInfo has only three inputs you need to worry about, and they're all fairly intuitive:
inputCurve takes as input the shape node of the nurbs curve you want as the position driver.
parameter, though non-descriptively named, controls where on the curve you want the transform object to be pinned to.
turnOnPercentage (christ, who names these inputs?) is a boolean which when on means the parameter input will be treated as a percentage of the curve's total length (I'll show you in more detail in a moment)

Blend Shapes Between Non-Matching Geometry: It's Possible!

We aaaaaaaaaall know -don't we? - that in order to apply an object to another object as a blend shape, those two objects have to match.

We know that, right? Of course. Everybody knows that about blend shapes!

Well it's a shame we all know that, because it isn't true.

Watch this:

You might be looking at that and thinking "But that's impossible! The source mesh is just a head, while the target mesh is the whole body!" And who could blame you? Normally when you try to make a blend shape between two objects whose geometries aren't identical, Maya throws it back in your face:

Vertex IDs & Vertex Order

Polymesh objects in Maya are made up of components, like faces, and edges, and such. And the king of components - the most fundamental - is vertices.

Every vertex in a mesh has a unique identifier called an ID that helps Maya tell them apart.
And it's important to understand a few things about these IDs...

Vertex IDs

The reason Maya is able to tell one vertex from another is because every single vertex in a mesh object has a unique number assigned to it called a vertex ID.
The quickest way to see a vertex's ID is to select that vertex and look up at the very top of the Maya window. The name of the object will be displayed followed by a number enclosed in brackets:

What's a Reference?

Referencing files into other files is a powerful feature in Maya.
When incorporated into rigging it allows for a way more non-destructive workflow.
This post will just be an intro to references for the uninitiated.

But first, let's review importation. We need to be sure we understand that so we can appreciate how referencing is different. And then we'll look at some of cool shit you can do in a reference workflow.

So I have two files here. Scene A:

and Scene B:

Joint Placement: Clavicles

Most people's first instinct is to pivot the clavicles from the top of the sternum, which is only sensible as that's where the clavicles pivot from in real life.

And if you were rigging a really, honestly, realistically proportioned human character with corrective systems emulating the muscles and such, that would be right. But 9 times out of 10 that's not the case, even if you might think it's the case.
Look at this character. Looks pretty accurate to reality, no? A reality in which people have time to work out, but still.

Joint Placement: Spine

There's an amusing Simpsons gag I'm very fond of. I'm sure you know it -
Some local children are watching a member of a film crew paint a horse in cow-print. One of the children inquires,
    "Sir, why don't you just use real cows?"
    
    "Because cows don't look like cows in the movies - you gotta use horses",
comes the reply, matter-of-factly.
And for good measure, another of the children then asks,
    "What do you do if you want something that looks like a horse?"

    "Hm... usually we just tape a bunch of cats together."

I find myself thinking about that statement often. "Cows don't looks like cows in the movies"
You'd be amazed just how often that kind of thinking comes up when trying to make something that needs not necessarily to look real under scrutiny but to feel real in the moment.

Knowing how to properly place points of articulation in a rig is about knowing when to use a cow and when to use a horse painted to look like a cow. That is - when to mimic reality and when to spit in its face.
Another way of thinking about this is the difference between simulation and emulation.