Introduction to Rigging: Planning Your Rig by Richard Kazuo & Danilo Pinheiro
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Welcome to the Introduction to Rigging tutorial series for Maya. Throughout these lessons for beginners, you will discover some basic technical concepts that will get you started in the fun and crazy world of rigging! And at the end, we will rig a complete biped character and leave with a short introduction on scripting, to automate simple tasks.
In this first chapter we almost won't be using the software itself - first things first! Anyone can follow a tutorial and get things working, but you can't rely on tutorials forever, right? You've got to understand what you are doing! So we're going to explain a little about how character riggers think, and how to optimize your work from the very start of the process in just about any kind of job.
Are you ready? - Let's do this!
Before taking any action, here is something you should always remember: Do not try to create everything that's in your mind, like some crazy, hungry monkey, before planning your rig!
Like with almost everything in life, if you don't plan before taking action you will most likely have a hard time trying to get things working! The process of building a character rig can be really complex, so it's a good idea to write a task list to avoid skipping important steps (Fig.01).
Pro Tip: First, let's play a little with our character and try to imagine how we can get good deformations. Good practice is to take screenshots from your model and draw over them. Try to figure out the ideal location of the skeleton, controls and pivots based in your character's proportions. Don't worry about this now; we will help you throughout this chapter (Fig.02).
In the rigging world, being organized is essential! Organization helps you to create easy-to-understand and up-to-date setups. Please, try to rename all objects, geometries, curve controls, nodes, etc. To sum up: everything you create and may have to use later.
Good practice in Maya is to use Groups (Any Mode > Edit > Group). Your rig must be as simple as possible. It doesn't matter whether you're working on a simple cartoon character or on a badass realistic creature: keep thinking in terms of solutions! They will come to you more easily when your rig and workflow are organized (Fig.03).
There are lots of object types in the 3D world, so it's easy to mix them up or delete what you shouldn't when you're on a tight schedule or working on really large scenes. Be careful to always name all of your objects, whilst keeping the names as clean and understandable as possible.
A simple pipeline only uses prefixes and suffixes for all nodes (objects in your Maya scene). The main idea here is team integration. When another person opens up your scene, they should be able to edit it easily if everything is correctly organized. Remember: please work with care in order to avoid unnecessary work for others and for yourself!
A simple yet efficient approach is to use three letters from the name of the character as a prefix, and also three letters from the node type as a suffix. And a good idea is to use underscores to make the names more readable. If applicable, indicate the node side using just one letter ("L" for left and "R" for right). Try to use underscores only when prefixing and suffixing, make the object name cleaner by separating words using capital letters between them ("l_greenColoredEyeball_jnt", for example) (Fig.04).
Whenever rigging creatures, be they humanoid, alien, animal, robotic, or whatever, always look for anatomy references in books and on the internet. Having knowledge about anatomy is a very important basis for creating good skeletons and muscle deformations.
Before you start your rig, take some time to look at the real world, as well as movie and image references. By doing this, you will most certainly have a clearer idea of what objectives to meet and how to achieve them (Fig.05).
Let's now discuss a little about some of the basic aspects of anatomy so we can position our joints in the best way we possibly can - this always ensures good rigging results!
We will quickly cover some deformation facts and limits, establishing those imaginary "mass blocks" to better understand how the deformation works in each area. Try to compare it to your own body to better understand how the rig should work.
The center of gravity (or center of mass) of a character is located in the spine, near the navel (we'd usually consider the waist joint as the root joint of all the hierarchy). When building the chest, be aware that it's the body part that deforms the least, while the abdomen is the most flexible region of the spine (Fig.06).
Head & Neck
We can divide the head and the neck into two main rotation points: one for the neck located in the base of the cervical vertebrae region, and the other for the head located at the base of the skull (Fig.07).
Arms & Clavicles
The clavicle is very important in order to get good arm movements, because the shoulder doesn't rotate more than on a horizontal line. With the clavicle, this limit can be surpassed, but remember that the clavicle bone doesn't rotate on its own axis (the one pointing to the shoulder). There is no limit on the shoulder's rotation, but the elbow can only rotate on one axis (using the biceps and triceps muscles).
The wrist bone also cannot rotate on its axis point. The relationship between the elbow and the wrist is very interesting because of the radius and ulna bones; they cross when the forearm rotates so that the wrist region rotates, keeping the elbow fixed (Fig.08).
Basically, we can consider that there are three phalanx bones for each of the five fingers in the human hand. None of these bones rotate on their axis point. The starting base of a phalanx can rotate on two axes, but the middle and last phalanges cannot (Fig.09).
The leg joint can rotate in all directions, and it's possible to rotate the ankle with it together, as if in a group. The knee just rotates in one direction, whilst the toes on the feet are similar to the fingers on the hand (with three phalanx bones for each), except that the toes only have two phalanges each (Fig.10).
Pro Tip: Remember to base your rigging on good anatomy whenever you can, but don't let it imprison your creativity! Sometimes we need to create mechanics that are different to realistic and natural anatomy in order to achieve the desired effects and deformations. Feel free to diversify using your creativity to get the best solutions for your needs.
That's it for this lesson! Be sure to draw and study a lot of anatomy and deformations! In the next chapter we will dive into Maya - our 3D software of choice - to put our knowledge into practice! That's right, in the next part we will test our planning on the real thing! A brief overview will show you how the software works and explain some of its main tools that are used for the rigging process, and we will also discover some tips and tricks on general rigging so you can speed up your workflow.