VW Ladybug Rigging

With a worthy model prepared, I could at last begin to rig.

The Ladybug's unique structure and proportions meant I couldn't generate or borrow a pre-made rig. I had to make a totally new one by hand.

Placing the joints themselves wasn’t too difficult. After a quick tutorial or two to familiarize myself with the rigging tools, it was just a simple matter of moving them into place and maintaining the hierarchy as I went.

I hadn’t quite decided how many joints I wanted in the creature's spine when I started, so I assembled the legs first and went back for the head, neck, and thorax later. Then, once I had the basic structure in place, I went through and oriented all the joints so they'd rotate in the right directions relative to the Ladybug's actual joints. 

After the skeleton was built out I got to work on painting the skin weights. Maya's auto-generated weights were a decent place to start, but they weren't perfect by any means. I spent a fair amount of time just checking to see if the vertices bound to each joint belonged there; more than once, vertices on one of the right legs would be bound to a joint on the left, or areas that belonged to the legs were bound to the body.

The ability to select vertices by influence and lock joints in the painting tool were vital to this process. If the selection showed odd vertices, I could lock everything except the joint those vertices belonged to and erase their influence from the errant joint. That way they could only be re-assigned to the correct part of the skeleton, and I didn't have to worry about re-checking any of the other joints before I moved on.

A handy trick I picked up during this process was to set a couple of keyframes while I was painting; if you set a key in the default pose on frame one and then key a different pose on frame two, it makes it very easy to swap between them and see how the skin weights are creasing the model. 

Finally, the rigged model needed some controls to make animation easier. The legs were each set up with both IK and FK controls, and controls to swap between the two. The eyes have controls for blinking and rotation within the socket, and there are controls for the chassis at the head, shoulders, and pelvis.

There are two copies of the joint skeleton in the overall rig; one bound to the model, and the other attached to the controls. Every joint in the bind skeleton is constrained by the equivalent joint in the control skeleton to allow an easy separation of the rigged model from the Maya animation controls. So, if I ever need to export the model without the controls, I just have to break all the parent constraints between the control skeleton and the bind skeleton.

The eye controls were mostly done with set driven keys. The individual eyelid controls were set up with an orient constraint on each eyelid's joint, and then a hierarchy of set driven keys was used to control each eye as well as both eyes together.

Now, I'm no animator, but the whole point of the project was to get the bug moving, so I had to at least try to show off some basic movements. This sequence shows off the flexibility of the body, the eyes blinking and rotating, and the legs moving up and down. In the future I'd like to try my hand at a walk cycle or an idle animation, but for now I'm content to call this project complete.