This section describes basic concepts concerning sets and surfaces. The following topics are discussed:

• “What is a set?,” Section 72.2.1

• “How do part sets and assembly sets differ?,” Section 72.2.2

• “What is a surface?,” Section 72.2.3

• “Regeneration of geometry sets and surfaces,” Section 72.2.4

• “Specifying a particular side or end of a region,” Section 72.2.5