Although capsules are not directly renderable, you can still show off or render your capsules/joints using a conversion process to generate a simple polygon cylinder from the capsules.

1. Select the capsule objects you want to create polygon representations for.

   

2. Select Muscle > Muscles/Bones > Generate Polygon Cylinders from Capsules from the main menu bar.

   New polygon cylinders with the same size and material color are created and automatically parented under each capsule. These can now be rendered.