Inverse Kinematics

Expert Topic for experienced builders.

Big idea

Inverse kinematics lets you place a target where you want the end of a chain to go, and Bottango solves the joints and keyframes to get it there.

Every movement you’ve made so far in Bottango has been using something called “forward kinematics.” Let’s imagine a hand connected to an arm, and you want to reach the hand out to grab an apple. With forward kinematics, the way you’ve been animating so far, you would first position the shoulder, then the elbow, then the wrist, to put the hand in the right position.

Inverse kinematics is a tool to help you make movements like that more easily and naturally. With inverse kinematics, you place the hand where you want it, next to the apple, and Bottango figures out where to move the wrist, elbow, and shoulder to facilitate the desired position of the hand.

The current state of inverse kinematics in Bottango

Note

There’s still a lot of work to be done to improve inverse kinematics in Bottango. What is here is only the start of what is planned.

As will be discussed later on this page, the current workflow uses IK to create keyframes on your joints. A future version will allow you to animate the target of an IK chain directly. Also, there is work to be done to improve the stability of the IK solver.