BASIC / Rigging 101

NOTE: 

This 101 on Rigging will grow overtime. With my 101 blog articles, I often update it and adding more information as I found more.

Ok, finally I am pretty confident to start writing post about Blender rigging and hopefully this can be useful for everyone.

I shall touch the basic of rigging in Blender first, and hopefully improve my writing to more advanced rigging in few posts to come.

I am actually basing my Blender rigging post from Nathan Vegdahl's DVD on rigging, with some extra notes based on my own understanding and experience with this area.

RIGGING IS AN ART

My rigging background is from Maya and I have become too familiar with Maya rigging workflow. I use Maya for over 8+ years now, my main are of focus is on character animation and rigging too.

BY NO MEANS, I am an expert in rigging, but I am about intermediate level. I am a teacher and mentor, so I know the general foundations pretty well.

While my Blender knowledge is 1+ year old. I am new to Blender rigging. So I am a student again.

I wish there are more Blender riggers out there can mentor or share their techniques. Or actual Blender projects that can push me better with Blender rigging. But I guess if I keep looking I will find a way.

So, I am not totally blind with rigging, but at the same time I am new to Blender rigging. Luckily Blender Rigging has some similarity to Maya. And more.

Anyhow, one needs to be brave to take first step and start learning.

BLENDER RIGGING

When switching to Blender, there is a slightly different approach. Conceptually, rigging in any 3D package is pretty similar.

But I don't like how people often oversimplifying things. Rigger cannot just switch from one package to another, there is always a bit of learning curve, but they may be able to learn it faster if they have experienced in that area.

Yes, rigging can be automated, like MIXAMO Rig or all kinds of automatic rigging script out there. However, they are good for generic character. There is nothing more beautiful than a nicely rigged character that works well for particular animation.

Using particular 3D tool, whether it is Maya, Softimage, Houdini, 3dsmax, Cinema4D, Lightwave, or Blender, a really good rigger needs to be flexible and switch his/her ways of thinking to suit the rigging tool set in hand.

It is not certainly not just different in UI. There is always advantages and disadvantages of one tool over another tool.

Quoted from Nathan Vegdahl: "Rigging is a mean to and end". So, every rig should have a purpose. When rig is complete, that is when animation can begin. RIGGING is just part of process to get to the final.

BLENDER WIKI ON RIGGING AND ARMATURE

http://wiki.blender.org/index.php/Doc:2.6/Manual/Rigging/Armatures

BLENDER DVD ON RIGGING

Nathan Vegdahl's "Humane Rigging DVD" is probably the only Blender Rigging DVD out there. I could be wrong, but this is certainly one of the BEST rigging DVD out there.

There are also some Blender rigging video tutorials from CMIVFX (the Mammoth Rig) but unfortunately they use older Blender version. They did try to kind of explain the difference, but still it is not easy to study rigging tutorial using old Blender when you are actually using new Blender interface.

STEP BY STEP RIGGING CONCEPT (this is the same on every 3D software)

1. Analyzing and preparing the 3D model to be rigged. Do clean up, make sure it has good topology. Make sure it is face the FRONT axis of the world.
2. Consult your animator and clearly understand on what this rig is going to be used for (what animation).
3. Break down the rig into smaller functions: Face Rig, Eye Rig, Leg Rig, Arm Lig, Torso/Spine Rig,  
4. Draw and place joints (or bones) in place.
5. Create controls and apply constraints
6. Paint weighting
7. Corrective Shapes
8. Body Rig and Facial Rig
9. Advance additional layers: Muscles, Dynamics

BLENDER EMPTY, ARMATURE EDIT MODE AND POSE MODE

Blender has its own unique way in handling rigging.

Like Nathan stated on his rigging DVD, there are 2 very important Objects related to rigging:
The Empty and The Armature.

Empty (or sometimes called NULL) is an object that only has Transformation information (position, rotation, scale). It cannot be rendered, but it appears on 3D viewport as a shape.

Armature is similar to Empty, but it has more to it. For every Armature object, it consists of bones hierarchy (aka bone chain), Armature has 2 mode to work with: EDIT MODE and POSE MODE.

To switch to Armature Edit Mode, you select the Armature object and hit TAB.
To switch to Armature Pose Mode, you select the Armature object and hit SHIFT+TAB.

Animator animates in Pose Mode. Armature is a single object that actually contains a lot of other objects and information, but able to maintain a Single Actions animation data.

BONES IN ARMATURE

Bone in Blender is simply powerful.

Bone in Pose Mode is Transform-able (Position, Rotate, Scale).
Bone can be saved as Pose Library.
Bone can be extruded.

As single bone can be squashed, stretched, and broken into segments (like for tail)

BLENDER CONSTRAINTS AND DRIVERS

There are also 2 features that relates closely to rigging: Constraints and Drivers.

This is quite common in all 3D package, but Blender has its own set of Constraints. In Blender, there are some constraints that are available for all common object (including Empty)

There are also more constraints that are only available inside Armature and can be applied when you are in Pose Mode:

Well, both seems to be showing all the constraints, but things like Inverse Kinematics is something that specific to Armatures and Bones.

BLENDER SPLINE IK SETUP

Spline IK in Blender is very interesting.

The Bone Constraint Spline IK itself is pretty simple, easy to setup. We need CURVE object that will drive the Bone. But how do we drive the CURVE? How do we CONTROL it? The answer is HOOK. Apparently we can also exchange HOOK with BONE!!

Grease Pencil => Curve => resample Curve (simplify) => Polygon Edge Mesh => Skin Modifier => turn this into a BONE CHAIN

HOOK Modifier - Blender Diplom

https://www.youtube.com/watch?v=Z7WXOM3iQYM

PARENTING CONCEPT

Ctrl+P to parent.
Alt+P to unparent.

In Blender, Bone is can be FREE, PARENTED, CONNECTED.

Maya users switching to Blender rigging will be a bit shocked to find this (yes, that's me). We understand the idea of having broken-hiearchy-joints, but the modularity of Rig and the Mesh in Blender is shockingly simple in implementation.

SILHOUETTE SHAPE ON CAMERA DEFORMATION

For a more advanced technique, you will something called Pose Space Deformation fixes.

I think Shape Tweak for Silhouette can be done using AniSculpt tool from Pepe:
http://www.pepeland.com/

PRESERVING VOLUME WHEN USING ARMATURE DEFORMER

ROTATING JOINTS FROM INDIVIDUAL PIVOT

Animator from Maya will understand this "gotcha!". By default, Blender Rotation is not actually based on Joint Individual Rotation. But you can do that if you like to, especially when animating something like tail.

In Maya, there is a lot of restriction on how we can transform Joints.

In Blender, we are FREE to Transform Joints as we please, to move them in space, to scale in any axis, to rotate in any pivot, it will all work, in a Animation Pose kind of way anyway. Probably the Rigger will tend to say => well, we probably need to rig cleverly.

However, in Blender, actually animator don't need to worry about that. Sometimes having JOINTS just moving and deforming character into POSE in 3D is more important.

In Blender, you might notice that ROTATION was not set to EULER by default, but QUATERNION. I was shocked too at first. This is so unusual. However, when animating for ROTATION, animator don't care about XYZ, but more about the SPACING and TIMING to get the POSE. They should not deal with GIMBAL LOCK stuff.

DRAWING AND PLACING BONES (Edit Mode)

Unlike Maya where you draw Joints and need 2 Joints to create Bones, in Blender you always start with a Single Bone. You cannot have just a single entity called Joint. I think similar concept is used in Softimage.

Blender default Bone axis is down in Z axis. Unlike Maya, which typically down in X axis. This means the bone Twist Axis is Z axis by default.

To turn on the Axis visibility of Armatures (all the bones) you do that on the Property panel:

JOINT ORIENTATION (Edit Mode)

Twist of Bone can be adjusted at anytime in Edit Mode. It will not affect the weighting or mesh.

QUATERNION VS EULER (Pose Mode)

Blender has 2 types of rotation for every object, which default on Quaternion.

Euler rotation is prone to Gimbal Lock.
With Quaternion, we don't need to worry about rotation, just pose your character.

MAYA: JOE ALTER L-BRUSH AND BRAVE RABBIT SHAPES

I often got the Pose Space Deformation mixed with Blendshape Corrective Shapes. PSD is probably a more advanced topic.

Something like this would be nice, L-Brush from Joe Alter.

http://www.lbrush.com/

NOTE: I switch back between Maya and Blender and trying to find a similar or equivalent tools in Blender. I think this is a good way to think of it. In Blender, we are all sharing skills and trying to brainstorm for the best and simplest of tool possible.

There is also this one from Brave Rabbit:
https://vimeo.com/80840525

CONTROL AND CONSTRAINT (Pose Mode)

Rig controls in Blender are BONES itself. They are created in Edit Mode, but you do the constraints in Pose Mode.

If you want to do parenting of object geometry, you do it in Pose Mode.

Shape of CONTROLS in Blender can be changed easily. Any MESH can become the SHAPE of controls.

BIND AND SKIN WEIGHT

Parenting Mesh to Armature will give you option whether you want to have Auto Weight. Blender Bone Auto-Weighting is really good. It's like Heat-Map and just works beautifully most of the time.

Select the armature and go to Weight Paint Mode

SPECIAL: ACTION CONSTRAINT

https://vimeo.com/8754153

HOTKEYS FOR RIGGING

USEFUL HOTKEYS WHEN DRAWING JOINTS/ARMATURES

E key = extrude bone
F key = connect between 2 Joint Point (you must elect 2 points only)

ALT +F
Reverse Joints

CTRL+SHIFT+C

To quickly add Constraints

BONE: Edit Mode

This is where you will want to work to edit, extrude bone, etc.

You don't need to Freeze Transform the Shape (unlike Maya)

BONE: Custom Shape

Need to be done in Pose Mode

Alt + P Clear Parent

When creating a quick control, you can quickly extrude bones and then Clear Parent

FOR CURVE

v = change vector handle type

USEFUL HOTKEYS WHEN POSING IN POSE MODE
A = Select All Bones (blue color)
Alt+R = reset rotationg
Alt+G = reset position
Alt+S = reset scaling

Don't forget there is also ARMATURE MENU apart from HOTKEYS:

WORK IN PROGRESS: Sverchok for Bone and Rigging and Procedural Character anc Creature Creation

Don't be scared. Everything will be simpler in time! Remember EDGE => SKIN MODIFIER => BONE.

You can create all kind of complex bone, procedurally and parametric. With a good setup, of course.

Just an unfinished work in progress. Sorry for Grease Pencil scribbles.

USEFUL HOTKEYS FOR WEIGHT PAINTING

RMB Click = select armature joint that you want to paint weight around the mesh points
F key = change brush size

USEFUL RIGGING RELATED LINKS

How to Rig An Arrow
https://vimeo.com/94007193

Rig - Animator Blog
http://www.riganimator.com/tips/animtip/

Suchan Raj Blog
http://suchanspot.blogspot.com.au/