In this section, we will learn how to apply the symmetric advanced mate. We will do that by applying the symmetric mate to the indicated surfaces around the shown symmetry plane in the following drawing. In this exercise, we are continuing our work on the assembly we started with the width mate: 

To set up the symmetric mate, we need to meet two requirements, a symmetry plane and surfaces to make symmetrical. To apply the symmetry mate, follow these steps: 

1. Check whether any of the default planes with the assembly match our required plane. In this case, there are none. Hence, we can create a new plane using the reference geometry function. The symmetry plane should be in the middle of the outer joint, as highlighted in the preceding diagram. The following screenshot highlights the settings for our new reference geometry plane:

2. Select the Symmetric mate by selecting the Mate command, scrolling to the Advanced Mates option, and then selecting the Symmetric mate, as highlighted in the screenshot:

3. Now, we will be prompted to set up the mate. We can set it up as highlighted in the following screenshot. Here is more explanation about the selection: 
   • Symmetry plane: Here, we can select the plane we created in step 1. Note that if the plane is not visible in the canvas, we can find it and select it by expanding the design tree available in the canvas, as indicated in the following screenshot.  
   • Entities to mate: This is the field under the Symmetry plane. Here, we can select the two surfaces we want to mate. In this case, they are the two surfaces highlighted in the following screenshot:

4. Click on the green checkmark to apply the mate. Once you confirm the mate, try moving the different parts to see the effect of the new mate. 

This concludes how to use the symmetric mate; we can start exploring more advanced mates. Next, we will explore the distance range and angle range mates.