By organizing related assets into sets, you can effectively manage complex scenes that have a large number of assets involved.
Like groups, sets are used for the selection and organization of items in a scene. Unlike groups, the visibility of sets can be animated, and the animation stored in sets can be cached.
Using sets, you can select a pre-defined collection of several objects every time you want to work with them. Once stored in a set, you can manipulate the whole set instead of each individual object.
For example, if you add all the nodes from a skeleton’s arm to a set, you can then scale, rotate, or translate the entire arm at the same time. When you manipulate a set, the proportions and positions of its objects are constrained.
Despite their similarities, the fundamental difference between groups and sets is that unlike groups, sets are exclusive. This means that while the same asset can appear in many groups, it can only occur once in one set. You cannot copy an asset or object from a set, you can only move it from one set to another.
The Sets window gives you a way to quickly transform and select a collection of objects, as well as toggle their visibility.