Take a look at the difference between joints vs. mates, and how to move items around in Autodesk Fusion. There are several tools available to you for creating and using joints. Let’s learn more about how you can more accurately position components and create complex motion.

Joints vs. Mates

To start off, what’s the difference between joints and as-built joints? Joints allow us to define the motion between components and the position that motion is relative to. As-built joints, on the other hand, create a joint to position components relative to one another and defines the relative motion.

It’s important to determine what kind of motion you want with degrees of freedom. There are three ways we can define the motion between components and the position that motion is relative to. The first is rigid motion, where we don’t want our components to move after alignment. The second is revolute rotation, where a component revolves around the x, y, or z axis, or even a custom axis. We can add sliders to move the object along the chosen axis, which is known as slider motion.

Using Joints in Fusion

After the components are assembled, we want to be able to track the location. Keep in mind that Fusion keeps track of each component’s coordinates. You can create a rigid group by connecting components so that they move as a single unit. Making a rigid group means that we don’t have to add more joints between components. Once the piece is in place, we can use as-built joints. They behave the same as regular joints, but it makes use of the current location of each component, rather than selecting a location where they will be aligned.

You can create a revolute joint to connect a pin and board, a slider joint to allow the piston to move up or down a cylinder, and use contact sets to enable mechanical motions in assemblies without joints.

There will also be factors like tangent relationships and motion links. If a revolute and slider joint is used together, for example, the relationship or ratio between movements can be determined. There are plenty of options when working with Fusion to create mechanical motion. The important thing is to understand that we’re locking down the degrees of freedom between components rather than doing it individually with things like coincident and concentric constraints. You can put joints on assemblies and allow them to move freely.

Now you know the difference between joints vs. mates in Autodesk Fusion as well as how to move things around. Check out the official Fusion YouTube channel for more valuable learning content.