The cogs and key animation was quite easy to set up. As the cogs would not be seen in great detail I didn't need to do any maths calculations to work out the correct rotation rate for each cog. I just set rotation values in the X-axis to zero on the first frame for all cogs and set another value of 360 on frame 25. As I did not want to go to the trouble of setting up joints for all the cogs, I baked out the animation instead. Originally, I left the key separate from the skeleton but I had issues getting it to animate correctly in UE4. I fixed this by adding the key joint to the main skeleton and skinned it. I used simple 0-360 looping animation the same way I set up the cogs but baking the animation was not necessary in this case. Baked Cog Animation Bind Pose used as a base for all looping animations During my research for flying birds I found a cool way to animate wings by using Expressions in Maya. The following link to the Maya Hacks Youtube channel
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. Simple FK skeleton rig with the root joint at the centr