Binding / Skinning

We need to connect our model now to the skeleton, we can do this via two methods, either rigid or smooth binding.  Smooth skinning provides smooth, articulated deformation effects by enabling several joints to influence the same deformable object points.  Rigid skinning provides articulated deformation effects by enabling joints to influence sets of deformable object points.  With our character, we'll be using Smooth Binding, as this gives us the best influence over the different areas of the character.  Now, with the character, I didn't create a neck, his head kind of sits in his clothing area, I create 'that' area from a simple sphere, and the head sits exactly in the pivot point of the sphere, and when I create the skeleton joint setup, I snapped to exact centre of this area too.  The head, we will be handling a bit differently to the rest of the character, open the Outliner and select the character's Head, and then select the character's Head joint.  Press P to Parent them together, that's our head now connect to the skeleton.  For the rest of the body we're now going to use smooth binding.  Open the outliner and select the following, make sure not to select the groups, but the actual objects instead : -

Once you have them all selected, select the COG joint, not the COG_Control, but the actual joint, then go to SKIN > BIND SKIN > SMOOTH BIND.  It should calculate for a few seconds then finish.  We've now connected the character to the actual skeleton, but.... we're far from finished, as you'll see.  Select any of your character's control and move them about, you'll notice the character moves along with the skeleton, but the deformation is quite off what we would like it to be, we now need to 'paint the weights'.  At each joint where it is bound to the character, it is given a weight of how much influence it has over the particular area, during the smooth binding process these are put in automatically, but they need some cleaning up.  Which is our next step.

To save us time, we'll be painting our weights on one side, and then using Maya's Mirror Skin Weights command to mirror them across to the other side.  Select the character's BODY, then go to SKIN > EDIT SMOOTH SKIN > PAINT SKIN WEIGHTS TOOL, and click on the options box to open the tools window : -

Within the Influence area, you can select each joint as you need it, and then paint the weights as you see fit for each section, we'll start with the COG joint, in the Paint Weights section of the tool box select ADD, then go to Flood, the character's body which should have been in black and white so you can see the weights, should now turn completely white, we're giving full weight to the whole body via the COG joint, then in the Influence section, select the SpineA joint, and then paint the weights for that one, you should end up with something similar to this diagram, I also suggest you turn on Vertex Display within the Display > Polygon Components section, as it will aid you when painting weights across the vertices : -

Remember to paint right around the character, once you've done this, select Smooth in the Paint Weight section, and then press Flood twice : -

Now select the SpineB joint, and do the same again : -

And again, select Smooth in the Paint Weight section, and then press Flood twice, select the SpineC joint, 

With the SpineC joint, notice I've painted up towards the arms as well, again, select Smooth in the Paint Weight section, and then press Flood twice.  Select the Neck joint, and then paint weights for that too.  A handy tip that I learnt to use quite often when I paint weights also, is to use Isolate Select when painting weights for certain body parts, that way I can concentrate only on the areas That I need to, such as the inside of the neck area  :-.  

 theYou can mirror smooth skin weights, either from one smooth skin object to another, or within the same smooth skin object. You can also mirror skin weights on selected components of the skin.  select Smooth in the Paint Weight section, and then press Flood twice.  Select the Head joint, nice and easy with this one, we don't want any influence, so in the Paint Weights section, select Replace, change the Value to 0 and then select Flood, remember to change the value back to 1 when painting more weights.  Now we need to paint the shoulder areas, select the Left_Shoulder and paint the weights : -

Select Smooth in the Paint Weight section, and then press Flood three times.  Now to use the Mirror Weights command, with the body still selected, select SKIN > EDIT SMOOTH SKIN > MIRROR SKIN WEIGHTS, that should take care of our Right Shoulder's weights.  Do the same for the LHip joint.  I'd also recommend using the Toggle Hold Weights On Selected when your happy with your painting to keep the painted weights corrected.  Now, painting weights is a huge and at times, tedious process, and as such I can't go into a really fully detailed breakdown of the whole process within the constraints of this tutorial, I will however, add a few more hints and tips.  Sometimes, there will still be parts of your model being influence by other 'non-related' parts, for instance, you paint the weights for the arm and fingers and all the rest and then grab your controller and move it around, for some strange reason parts of your character body seem to be moving along with the arm, to correct this, select the characters body, go into the paint weights mode, and then select the arm, say the Left arm, start from the Left_Elbow joint, select Replace with a value of 0, and then flood, and then work your way down the characters arm through each of the finger joints too and do the same each time, this should fix the extra influences on the main body.  Another tip is to toggle between wireframe and shaded whenever possible, as this can let you see some vertices being influenced where you wouldn't normally see.  Another tip is to paint your weights on selected areas with the affected joint in it's extreme pose, i.e.  the fingers would be best painted in their curled position, one by one, paint the influence, and then hold the weight and set the finger back to it's normal position.

  As I previously mentioned, the painiting process can be very intricate depending on each models needs, and I really can't go into the sort of depth needed within the scope of this tutorial, but all I can say is you will get better and better with practice.  You can download the final model here with the weights already painted, although they aren't perfect, but maybe you can work on your weights here, I should also mention that once you've animated your character, the final thing you need to do is smooth the polygon object once or twice depending on your requirements and render the high-res version of the characer, using the low-res one to animate with : -

Final Scene - Maya 4.5 Only - Zip File (653kb)

Conclusion : -  In conclusion, there's still a lot I have to learn personally myself in terms of character rigging, this tutorial was part of my own learning process, it was aimed at beginners, and hopefully, there's been some benefit there.  Looking back over it, I'd probably do a few things differently, especially the knee area, I wouldn't have it so far forward, which means when I'm animating I have to compensate for that, moving on, I would insert the knee join a lot closer to the middle of the actual leg.  Anyway, thanks for reading along and I hope you found this tutorial useful.

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