Hello and welcome to another developer blog post from BubbleZap Games! Today we'll be exploring some of the behind the scenes of the animation process for Air Kingdoms. We'll go over the thought process and explain the steps we take when creating assets for the game. Then finally we'll show off some of the playblasts we've created for a finalized look at the animations. So sit back, relax and enjoy the show!
When creating animation assets for Air Kingdoms we took sort of a different approach than a traditional game using the Unity engine. Every studio has their own process for creating animation assets for their titles and there is usually a general way of going about it. But since we are developing a game on the mobile platform we needed to keep an extremely low overhead to keep the game running smoothly. For this we decided to bake our animations and export them in pieces. We'd then take the exported FBX files and assemble them in Unity and add them to the game. Since we have so many units on screen we have to do this to keep the draw calls low and keep the game running smoothly. Taking those factors into consideration we kicked off our character pipeline. When implementing a character we took a very common route, after the 3D artist modeled and textured the character they handed it off to the animator. The animator then takes the model and creates what is called a rig. The purpose of the rig is to act like a skeletal structure for the model. The bones of the rig go inside the model and are used to control the movement of the geometry that the player can see in game. Here is an example of a model without and with a rig attached.
Next the controls are created for the rig. Controls are just visual objects/curves the animator can see to select and move parts of the characters body. Creating controls can be a lot of work, but having really good and customizable controls is a valuable asset when animating a character. Here is an updated rig with controls attached.
So after the character rig is complete we move on to animating the character. Usually in the animation portion we break it down into phases. The first phase is usually the blocking phase, after we have an idea of what we want the animation to look like we simply pose the character into different poses we'll use later on in the final animation.
The next phase if very similar to the first except we break down the blocking phase into smaller steps which creates a better look at the animation we are looking for. This phase starts to give a final motion to the poses and lets us get our timing down a little better.
After a few iterations of the break down phase we come to the final stage of taking the animation curves and setting them from stepped to linear. After completing this step we polish the entire animation. Usually the final polish stage will have little tweaks here or there but mostly our animation is complete and we're ready to show our team.
And adding some polish.
After we finalize the animation and the director signs off on it we move onto the exporting process. Since we're baking animations the exporting process to Unity is a bit involved, nothing too extreme but small steps that need to be followed in order to get a good working export in the engine. We first need to bake the animation by selecting all the bones and the geometry and hitting the "Bake Animation" button in our 3D program. After baking the animation we need to delete the IK handles from the rig. IK handles are just a smaller tool used to help the rig move how we want. Once those are deleted from the rig we simply delete any non-deformer history he had on the geometry. This is done by simply selecting the geometry and hitting the "Delete Non-Deformer History" button located again in our 3D program. Once all these smaller steps are complete we then select the portion of the character (depending on either the upper or lower portion) we'd like to export. We also select the base of the rig than export to an FBX file. This character in particular has three portions that needs to be exported then unified to work in game, his upper, his lower and his weapon.
And that's about it. We hand off the parts to the engineers and they get it working in our game with their programmer magic! The animation portion is a fun and rewarding part of the development process and it's always amazing to see you game come together a little more with moving characters on screen. Thanks again for taking the time to check out our development blog and stay tuned for more from the world of Air Kingdoms!