The Generic Line is used to tie Constraints to model elements on a Sequence diagram for SysML and UML 2.5.
How to model a constraint
•Select the constraint symbol from the Draw toolbar, add it to the Sequence diagram, and then name it. The border of the constraint symbol will disappear after drawing it.
How to model start and end regions of a Time or Duration constraint
1 Use the Generic Line symbol and draw a line from the Lifeline to the top of the Constraint symbol. An Associative dialog will open after drawing the line – leave the default ‘to’ direction of the Flow (Sequence) toggled on.
2 To adjust the arrowhead of the Generic Line after drawing it, right-click the line, and then choose to open its Associative Properties.
3 Draw a similar Generic Line from the Lifeline to the bottom of the Constraint symbol. You might need to insert line segments into the line after drawing it to make it orthogonal – to do so, right-click the line, and then select Insert Line Segment.
How to tidy up the Generic Lines
•Make sure their line style is set to Straight-Orthogonal (to access this setting, select the line and select Format > Symbol Format > Line Style).
•Add additional end points into the line if necessary (right-click the line, and then select Insert Line Segment).
•Make sure the arrowhead points at the Constraint (right-click the line, and then select Associative to open the Associative Properties dialog, within which you can specify the direction of arrowheads.
