Families sleep together on larger hammocks, which are decorated and meticulously constructed for flexibility and strength. They are made of rope, twine, and strong woven mats. A large central mat is woven in a decorative pattern, which is then affixed to a rope support structure. The finished hammock is then affixed to branches of Hometree. The Na’vi refer to this large family hammock as a swaynivi, ‘family hammock’, nivi being the general term for a sleeping hammock.
Because of the fine craftsmanship, swaynivi can last for more than twenty Earth years. It is up to family elders to decide when a new hammock is needed. Construction takes place over a period of months and generates a good deal of enthusiasm within both the family and the clan as a whole; everyone contributes to the effort. A great deal of time is spent gathering the correct materials, and it is during this process that most of the familial bonding takes place. The construction itself is a relatively informal and straightforward process. As the hammock nears completion, several ceremonies take place to honor and acknowledge the hard work. When the new hammock is finally installed and the old one is removed, there is a ceremony in which the old hammock is burned on a pyre in a serious, respectful manner. At the end of this ceremony, the family puts on a celebration with food and dance in honor of the moment of renewal.