Volume-Face Relationships – Shells
Shell – an unordered collection of two or more faces that bound a volume
- Outer Shell – defines the outer boundary of a volume
- Inner Shells – define any inner boundaries of a volume (i.e., “bubbles” within the volume)
- A collection of one or more faces that are connected to one another, but that are not connected to the outer boundary of the volume, form an inner shell even if they do not enclose a space
A face can appear twice in the same shell, once in each orientation