Animation Research Blog – 01 – Wings
(This blog was meant to come out last Sunday but I forgot to publish it)Hello, this is my second blog in my new blogging routine. The plan is to 3 blogs a week, a random blog on Tuesday, a project blog on Friday, and a research blog on Sunday. This will force me to think more critically about what I am doing and to force to do more research on subjects relating to digital art and computer graphics.
This entry is a research entry on the subject of bird animation, I’ll be exploring bird anatomy and common methods used in the 3D industry to rig and animate birds. All the knowledge I gain from this research will apply to the work I am doing for my rapid project (more on that in other entries).
Men Can Fly
Wings may seem complicated as there is so much going on, but as I did my research they’re underlying structure is much simpler than I thought. I started by looking at the bones as I would have to imitate their positions if I wanted the best result for rigs bone placement. So their wing bones are split up similarly to a human arm, there is a shoulder, an elbow and a wrist. The only difference is that the forearm is longer and there is a single finger(digit). Birds bones are much lighter than other animals to allow flight, the inside of the bones is similar to a honeycomb, this way they are still light while remaining strong, the bones are actually lighter than the feathers.
Most of the bone and joints are named the same as the one found in the human arm so it is easier to understand the function and movement of each bone. For my rig I firstly created three main bones to define the main movement pivots for the wing, I then used the refine tool in the bone tool menu to add extra segments to allow for more organic deformation when the wings are flapping. In real production environments, they would add a segment for each feather on the wing, but that involved extra time I did not have for this project. So I added extra segments at a less frequent rate and it gave me a really good result anyway.
Do you even lift off bro?
The actual wing muscle might be hard to identify as most of the time it is covered by all the wing feathers. But if you have ever seen a whole chicken in the supermarket that is pretty much what they look like. As before, the muscle names are very similar to that of a human. It is important to understand the muscle system of a bird even with a simple model because it allows you to differentiate between what should be part of the base mesh and what should be feathers. Another part that should be mentioned is that it is not as important to understand how they fold if you are not going to see the bird tucking its wings properly. In my case I only worried about the model working for the bird in a flying and occasionally diving pose.
The hardest part of the wing to understand is the feather, how they work and how they are arranged. The actual flying feathers are the long individual feathers, they are divided into primaries which are the longest and most important for flight, and into secondaries which are the ones closer to the body. the flying feathers are the thinnest and stiffest of all the feathers. The amount of these is dependent on each species of bird, larger birds tending to have a greater amount of flying feathers. The coverts are layers of softer feathers that, as their name suggests, cover the the primaries allowing air to pass by the wing more smoothly. The coverts are divided into 3, the primary coverts which cover the primary feathers, the secondary coverts which cover the secondary feather and finally the marginal coverts which in hand cover the other two sets of coverts.
In terms of modelling it is just important to identify the layout of the feathers and how they overlap. But when it comes to rigging it is really important to identify where each feather comes from and how the fold so that you can get more realistic control over the feather. In some cases they use a spline IK setup for the feather to allow them to move and bend more naturally, but that process is very repetitive and in my case is just simply assigned each feather to a specific bone.For my feather layout I excluded the marginal coverts as it was much more work to make them look good. So in the end the wing looked better without them, although if I had extra time I would definitely add them.
In terms of animating the wings i have found this link very informative and interesting Brendan Body Flight Tutorial, he worked on that owl movie and he did some really extensive research for the film. But beside that I didn’t really get into it as I myself wont be doing any extensive wing animation. It was important to understand the movement so i could give the other animators the best controls and setup.
That is about it, I’m sure there are other things I researched for this rig, but none of them come to mind st the moment, to finish here is a video of my rig in action.