As I am relatively new to rigging and this was my first attempt at rigging a bird, I decided to make things as simple as possible by keeping the total number of joints in the skeleton to a minimum. The first version of the skeleton uses the older wing which is not split into sections. More on this further down the page.
The root joint is placed at the centre of the torso and branches out to a neck joint to control the head movement, shoulder joints for each wing, a tail joint for vertical tail rotation and finally, leg joints which branch out to the claw joints.
In the animation, the Bird character needs to open and close its claws during an action scene. This was the most involved part of the skinning and rigging process as it was quite painstaking work to paint the weights in such a tight area without painting adjacent faces. Luckily, I was able to toggle isolation for selected faces using the Ctrl+1 hotkeys.
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| Simple FK skeleton rig with the root joint at the centre of the bird |
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| Skinning the older wing geometry to the wing shoulder joint |
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| Skinning the claw geometry to the claw joints |
After skinning the bird, I created a simple controller using NURBS curves. I set limits on the X and Y movements for the linear controls. For the leg movement controls, rotation values limited to 0-360 were used.
Rig controller with limits set on translation values
After setting up the controller, the rig needed to be connected to it through Set Driven Keys. As well as setting limits on the controls, limits were also set on the movement of joints to stop geometry moving in an unrealistic fashion, such as the wing intersecting with the body if rotated too far.
The claws took more work as they have more joints. When the controller is in the extreme left position, the claw is fully open . I set the controller to the extreme right position and rotations were set on each claw joint so that the whole claw was closed before setting driven keys. Now I was able to get a nice open and closing action by moving the claw control from left to right.
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| Driving the rotation of the wing by connecting the wing controller to the wing shoulder joint with Set Driven Keys |
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| Setting rotations on the claw joints and connecting to controller with Set Driven Keys |
I wasn't happy with the wings as they looked too rigid when animated. Some work was needed to break them up into three sections. I used the Poly Chip Off tool in Maya's Modelling section to break each wing piece into the three sections. I also fixed the UVs on the altered geometry being careful not to move any of the other UV shells so I wouldn't have too much fixing up to do back in Mari.
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| Completed rig with X Ray Joints turned on |
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