I have a blue system function that was transitioned from the operation analysis to realize an operation activity. Cool that makes sense.
As part of the SAB I created, I broke this function into two smaller functions. However, in the SFBD, I can’t created a “Contained In” relationship from the two sub-functions within the parent function. Why is that? Isn’t this the point of the SAB and SFBD workflow?
Hum, it is not exactly clear why it is not working, and I can reproduce the issue (which seems to be one from my perspective).
As a workaround, you can drag and drop functions in the project explorer (Tree View) to create the desired hierarchy, it will do the trick.
Maybe just an attention point: when transitioning your Operational Activity into a System Function, do not assume that there is a general pattern where the System Functions you are created are going to be refinement of the functions you transitioned. If you do that at every engineering perspective, you’re duplicating your model at each layer, which is not what Arcadia engineering perspectives are bout (There not refinements of the previous ones, but realizations). More on this in this thread for example: Capabilities in LA/PA
Understood! For the most part I’ve been modelling the realizations and there hasn’t been duplication through the layers and primarily used the SFBD to group related functions into a higher combined function that can be used where the granularity isn’t needed. However, some cases the refinement is needed at the lower levels to be clear that a function includes certain behaviors (ex: IBD equivalent in sysML) that isn’t important at higher levels.
Ex: Spacecraft needs guidance, navigation, and control capabilities, which is realized by lower level capabilities to estimate the state of the vehicle, estimate the environment of the vehicle, control the attitude of the vehicle, control the position of the vehicle, etc. This can be further realized as one or more software and hardware components to do meet those capabilities. At the lowest level a software component realized at middle layer may need to be refined into multiple sub-components to handle all of the things related needs to perform the tasks.