It’s simple to edit the rotational axes for joints to achieve the desired orientation and movement. This is a part of our series on 3D art and animation basics. If you need tools to get started, see our guides to the best 3D modelling software and the best laptops for 3D modelling.

Usually, upon creation, a joint’s orientation is set so that it automatically points to its parent in the hierarchy. This makes animation more predictable. However, there will be times when you may need a different primary axis, such as when working with a game engine or to help reduce gimbal lock.

There will also be times when the axes are reset or even changed by accident, so they need to be corrected. Fortunately, editing rotational axes is very easy to do and you have full freedom to configure them any way you like, and at any angle too. Let’s take a look at how you would approach this in a simple, three-joint arm setup.

01. Broken rotations: The joints in this simple arm setup have been reset to match the world orientation. The issue is, as you rotate the shoulder, the elbow joint moves away from its original location, meaning this isn’t a natural movement and would prove difficult for an animator to work with.

02. Set up your orientations: What we need to do is reset the orientations, and in most applications there is a simple tool to help do this. Usually there are three options: Primary Axis is the axis that points down the joint, with Secondary Axis pointing away from the joint. Secondary Axis World Orientation is which direction the secondary axis points in.

03. Reset your orientations: If we use X as the Primary Axis, and Y as both the Secondary Axis and Secondary Axis World Orientation, our axes are now fixed with X now pointing down the joints and Y pointing up. Now, when we rotate the shoulder, the elbow remains in place. The same goes for the forearm and the wrist.