Since we need to pose our character for this project, we must create an interior skeleton. Using the joint creation tool, the skeleton for this arm is drawn out from the root node outwards. Since this is just an arm in this demo, I have begun with the shoulderblade rather than the hips. I have also utilized the double shoulder bone method for the skeleton, allowing greater control of upwards and backwards flexing. Once the skeleton is drawn into place AND NAMED IN THE HYPERGRAPH it is time to smooth bind it to the LOW POLY MESH. Binding directly to the high poly mesh can create disasterous problems when needing to paint skin weights. Below you see my smooth bind options. Note that I keep my max influences low, as well as my dropoff rate low, which i find gives a cleaner initial bind. Once bound as well, I make sure to SET my PREFFERED ANGLE which will allow me, in conjunction with Go TO BIND POSE, to reassume the bind pose at any point while posing the character.

Inevitably the binding will need to be tweaked to make sure that the bones defore the skeleton in a way that simulates the stretching of the muscle. In painting my skin weights I always, ALWAYS make sure to paint from the root node downwards, in this case painting the shoulderblade weights first, the finger weights last. I also make sure to always Add or Replace weight values, never Subtract them, as the subtraction will RANDOMLY RE-ASSIGN that section of skin's weighting to some other bone, taking control away from you. To also assure that I am painting my weights to diminish as many f@*kups as possible, I will usually Flood my weights downwards. The purpose of this is to insure that the tip of the pinkie bone isnt randomly effecting the shoulder. In this way, I can make sure that if there is some small error in the rigging, It will be much more localized. So, here is my tip to you.... use the Isolate Select feature when painting your skin weights.

Below we see I am about to paint the initial weighting for the elbow. Sooooo, I will select everything below the elbow on the skin and choose view selected.

Next I will switch back to object mode once the rest of the arm is hidden and I can flood the weights for this section on downwards to 1.

Unchecking the view selected shows us that the weights were flooded nicely for this region. Using the smooth feature, we can taper the falloff from full bend to no effect. While tweaking these details, I often find it helpful to positon the mesh in maximum flexion to see how the falloff works, and whether or not the muscle groups are behaving accordingly.

New in Maya 2011+ is the ability to use a Color Ramp instead of just black and white. Enabling this feature allows for greater visual clarity when trying to find small weights.

Also new in Maya 2011+ is the Hammer Weights tool. If you have a stray weighting on a single vertex (or a few verts) just select them and hit the hammer icon shown below and the weights will automatically be redistributed to the surrounding average.

Here you can see a before and after:

 

Rigging the body for Pose in Maya (Interactive smooth bind):

The new new Interactive Skin Bind replicates systems already in place in Max, Mudbox and Zbursh, allowing for quick, artist friendly skin binds. While, this doesn’t allow for as much control as traditional skin weighting, it does go very fast. You can find the option under Animation-Skin-Bind Skin-Interactive Skin Bind-options box. This creates a capsule, which you can re-size around every bone for quick weighting. NO MORE EXCUSES ABOUT NOT BEING ABLE TO PAINT WEIGHTS!!!!!

You can find this capsule tool under Skin-Edit Smooth Skin- Interactive Skin Binding. The best part is: the whole system is symetrical by default. Notice how in the image to the right, the capsules for the right side match what I am editing by hand on the left. As long as you mirror your joints!

Watch the system in action here:

 

Transfer Skin Weights
Well, the low poly mesh is rigged, but what If I need to render with my high-poly sculpt visible instead. Since we have already uv'd the model and since the two meshes are identical in terms of construction, we can cop the skin weights. Our first step is to also smooth bind the highpoly object. Then under Animation-->Skin-->Edit Smooth Skin we can Copy the Skin Weights (shown below).

While the high-poly object's weights may need some final tweaking, we can see that the weights have copied and my mesh will bend in a very similar way, allowing me to animate using the low poly standin, but render off the high-poly shell.