Software is ubiquitous in modern systems, yet popular MBSE processes and frameworks don’t consider it in much depth. Why don’t more people in the MBSE community talk about software? For many systems engineers and process designers, software is not their specific area of expertise. But software is present in virtually all SysML behavior models and accounts for a preponderance of the complexity and cost of many of them. In this paper, we review SysML Behavior models, examine the difference between embedded and non-embedded software, propose some requirements for generating useful code from MBSE models, and illustrate these requirements by example. Finally, we propose some use cases for using code generation in an iterative MBSE development process, and introduce the pattern of Model-Generate-Test.