SysML Parametrics: You can use custom stereotypes keywords «i» and «o» on constraint parameters to indicate their intended use (causality) as (i)nputs and (o)utputs on ConstraintBlocks

The ConstraintParameters of SysML ConstraintBlocks do not have an intrinsic direction. The constraints of ConstraintBlocks usages are applied across a network of constraint equations via BindingConnectors.

It can, however, be useful to indicate the intended use (the causality) by applying custom stereotypes «i» and «o» to indicate the intended use of ConstraintParameters as (i)nputs or (o)utputs:

Pro: Makes it much easier to trace and analyse parameter dependencies.

Con: Can compromise reuse when the dependency flow is different (but one can always then just hide the display of the custom stereotypes).

In MagicDraw SysML Plugin there is a symbol properties feature Position Of Labels. Setting this to the mode 'Inside' is recommended in this case, as otherwise the applied stereotypes «i» and «o» may "float" outside the small parameter box symbols.

This SysML modelling tip is frequently combined with: