Is your feature request related to a problem?

Lifelines are currently untyped or referenced to other blocks which inhibits traceability between behaviors (operations) and components. I would like to be able to assign types to lifelines (from other preexisting blocks). Alternatively, (better) would be to display existing parts (blocks or Actors) on interaction diagrams as lifelines so they are inherently tied together with the associated messages/operations.

Describe the solution you'd like

See SysML Table 12.1. "The Sequence diagram describes the flow of control between actors and systems (blocks) or between parts of a system."

The individual lifelines shown in the spec are pre-existing components in the model. Either an unnamed block (just typed), a named block (e.g., a typed property from an internal block diagram), or an actor. Creating lifelines from blocks/actors/properties may be the more optimal route as opposed to adding a type selector for a lifeline.

Related: the SysML site specifically calls out avoiding using strings as the messages and instead using operations/signals. It would be useful if new messages introduced in the interaction diagrams could be tied back to their source block/actor as operations. Auto-assigning the operation to the source block might work initially. However, it may be desirable to assign operations to ports on the source block instead of the block itself. The corollary is that operations already defined on the originating block (or its ports) could be selected when inserting a message instead of generating a new operation on the source components.

Example

Shown below is the intended end goal with an interface behavior diagram and accompanying port definition for the control unit taken from Holt, "Systems engineering demystified", Pakt, 2023

Describe alternatives you've considered

Noted above