Within Fusion 360 you may have noticed that in some commands such as, Mirror and Pattern. There is an option to select Faces as the "Pattern Type". You may have asked yourself, why and when would I select Faces over the other options like Features, Bodies, Components.
So, here is a quick example on how the Faces option will result in a different solution compared to when selecting the Features option. We will start with a few primitive shape to demonstrate. FYI, This is one solid body.
First we will mirror the bump out labeled "1" as a Feature using the bottom of the part as the mirror plane.
For each Feature selected (rectangular shape and the extruded text) in this case. The result created a new solid body for each of them because the mirror plane that was chosen pushed the new features off the original.
If the mirror plane would have kept the new features conjoined to "Body1" then this would have been the result. Still a single solid body.
Now, let's take a look at the Faces option. Here I will select the second rectangular feature with its extruded text labeled "2" and the original mirror plane (the bottom of the part).
When selecting the Faces option and the result becomes detached the command will in a sense heal itself and extend back to next leaving you still with a single solid body. Here I show the original Mirror Feature option next to the Mirror Face option for reference. Of course if when using the Faces option and the mirror cannot extend back and hit something (like the result is out in space) the feature will fail unlike using the Features option where it will succeed.
As always, I hope this finds you well and back to sweeping mines!