SysML FAQ: What is the relationship between SysML and MBSE?

Unfortunately, de facto standards for Model-Based Tools, Model-Based Architecture Frameworks, and Model-Based Processes have not yet emerged. Commercial and open-source Model-Based Tools that comply with the SysML language standard are available, but many improvements are needed, as you can see from the tool reviews on the MBSE Tool Reviews web. Model-Based Architecture Frameworks that organize System Architecture models defined with SysML are only required for defense applications, where DoD Architecture Framework (DoDAF) prevails. Model-Based Processes that support large-scale MBSE applications are the least mature quadrant of the System Architecture Tetrad pattern.

Bitter experience has show that MBSE projects that fail to properly balance the four parts of the System Architecture Tetrad tend to achieve poor or mixed results.