Structure and analysis groups are very convenient for customized analysis, parameter sweeps and optimization, and in general they provide a good way to organize objects in your simulation when dealing with complex structures. The object library provides many ready-to-use groups but you can build your own.
Generally, when you create these groups you want to make sure that the properties of the objects inside can only be accessed through the group properties. For example, if your group is composed by an array of spheres it is convenient to make sure that the radius of one of them cannot be changed by editing it separately. This helps to keep track of the setup, especially if you are dealing with a large number of objects. To prevent changes to child object from being saved, check the option construction group as shown below. When the construction group option is used, objects inside the group can only be added through the group’s setup script, so an object outside the group cannot be added to it.