Researching and creating the biped rig - Part 1

I chose to rig using a biped as I felt it would be quicker and easier than creating all of the bones myself. As my character is a basic humanoid a biped works well, but if I were making any other creature I would use a different method.

Before creating my own biped, I read through an informative text tutorial by Jason Wiser, which goes into a lot of detail about the key stages of rigging. Although I found the tutorial extremely useful for the most part, there are areas where I find that visual examples are needed to get a good understanding. For that, I watched through a 40 minute rigging tutorial by Mike Pickton, which gives a basic demonstration of the rigging process.

I will provide blog updates as I rig my mesh and give a brief explanation of things I've learnt at every step.





1. Preparing the mesh

• It's suggested that the character should be created in a T-pose with palms down and fingers somewhat spread, so that the the skinning envelopes don't grab the wrong vertices. As I plan to add Morpher facial animation, I detached the head from the body before I began.

• Organisation is important for finding certain parts of the body or bones, so I've labelled every part of my model with the prefix 'Larthur_', followed by a suffix such as 'EyeR' or 'EyeL'. Organisation is also paramount when working in teams where other people will be using your model, as it allows them to easily find what they're looking for.

• Scaling the model is vital to do it before adding the biped because once a model is fully skinned/rigged it's difficult to re-size everything accurately, as I learnt the heard way. After doing some basic skinning on a test biped, I'd realised that my model was around 21' in height, and I had to re-do it from the start at a more appropriate 6'7" height.

• Lastly, it's good to make sure that the character is in the right position before adding the biped. The feet should be on the "ground" plane (0,0), and the centre of the shoulder and ankles should be aligned with the Z-line.

2. Creating and setting a biped

• Creating the biped can be done from the Create/System, and should be aligned to (0.0) at the mesh's feet. The different parts of the biped are automatically named in a logical way, but should be added to a new "biped" layer in the Layers Manager.

• To start scaling the bones in the biped, Figure Mode has to be turned on under the Motion panel. Under the Structure rolldown I changed the number of fingers and finger links to match my mesh, and only gave it 1 toe as the mesh is wearing shoes.

• The rest of the body is positioned to match up with the mesh, with 3 segments along the spine for accurate bending. The arm joint stays quite deep inside the shoulder mesh so that the armpit crease looks good when animated.

3. Biped animation

• It's good to set up an animation for the biped before skinning, because it means you can play it as you skin and see how the mesh deforms. To animate the biped you first have to go out of figure mode, and then animate it in the same way you would animate a finished rig. 

• Although the tutorial suggests using a walk cycle as the animation, I decided to follow the YouTube video and create an animation which tests the movement and rotation of each individual body part; this was so that I could test each limb to the limits of its movement.

• To animate using IK controls you can move the hands or feet, and to animate using FK controls you can move the legs and arms.

• Although the Auto Key button works the same for bipeds as it does for other animation, if you want to set an individual key at a specific point you have to use the red "Set Key" circle in the Character Studio Motion panel.