Waseem and Sadiq Figure 9. Parametric diagram for mass and power budgets. properties and their parameters, along with other properties from within the internal block context. In this way, the parametric diagram can show how constraint blocks are combined in a particular usage as a set of constraint properties. A constraint block in SysML is a modeling element (a special kind of block) that defines a Boolean constraint expression evaluating to either true or false. It is a mathematical relationship that is used to constrain value properties of blocks. The variables in a constraint expression are called constraint parameters. They generally represent quantities, so they are typed most often by value types. APRIL 2018 For demonstration of SysML parametrics, we have modeled mass and power budgets of NSS-1 in this article and used the ParaMagic plug-in of MagicDraw for dynamic analysis. The corresponding parametric diagram is shown in Figure 9. The procedure starts with requirement diagrams in which the constraint blocks have been created to calculate the mass and power margins in the budgets, keeping in view the mass and power requirement by the user. This scenario is depicted in the SysML requirement diagram with the verify relationship. A test case or other named element can be used in a similar fashion to represent any standard verification method, such as re- IEEE A&E SYSTEMS MAGAZINE 31