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Sequence Diagram Sync/Async and Time Constraints

I have a few questions about the Sequence Diagrams as implemented in Astah.

When either a Synchronous Message or Asynchronous Message is added to a Sequence Diagram, a block of time is shown at both ends of the arrow. According to the SysML specification, it should be possible to show messages with no time block shown (indicating no duration at either end of the message). How do you hide the boxes in Astah? (I think these are called "Execution Specification" in the SysML spec). In Astah, I can't figure out how to remove, hide or reduce them to invisible size.

Second Question: According to the reference material I have seen, the duration constraint should be able to be specified for the Execution Specification time blocks. When I try to insert a duration constraint, I have to select the message arrows, not the Execution Specification time blocks. Is there way to show the duration constraint on the time block and not between arrows? Sometimes there is no arrow at the end of the time block.

Thank you.

Product: Astah SysML

Hi mp,

Thank you for your questions.

1: Currently you cannot hide the Execution Specification with Astah SysML. But it is available with Astah Professional edition. Image Text

2: I'm sorry but you cannot add the duration constraint to the execution specifications now. We'll consider implementing in the future release.

Have you tried out Astah Professional before?

Thanks, SJ

Thanks Satomi. I really don't understand why I would need to buy another package to get features that Astah SysML should implement. I only need SysML, not the other features of Professional. I'm asking about a basic feature of SysML, not an extension or addition to SysML.

Looking at the description page for Professional, it doesn't implement all of SysML. BDD and IBD are not listed in the diagram list. So why would a SysML user think he might need to purchase that software? Do I need to purchase both SysML and Professional to get all of the available SysML features?

Also the comparison page says Astah SysML supports package diagrams. It doesn't have package diagrams.

In Astah SysML here are many features that are inconsistent with the basic properties of the language. I understand the cost is low, but it would be best in my opinion to either implement a feature correctly or leave it out completely (and be honest about it on the website that it's not implemented). It is misleading to show a "duration constraint" tool, but the tool implements a constraint that is not consistent with the SysML specification.

Hi mp,

Thanks for getting back to me so quickly. First of all, I agree with you. I mean Astah SysML should have the same ability for the Sequence diagram that Astah Professional does, and more than anything, it should comply with SysML specifications correctly.

I didn't mean to ask you to purchase Astah Professional. I was going to offer a free license of Astah Professional until our team updates Astah SysML with the ability. A lot of our customers would start with Astah Professional, so I thought you might have checked out Astah Professional before you touched Astah SysML.

Regarding the package diagrams, we'd like you to create it using BDD. This is noted on FAQ but should have been more clear. Sorry about that.

Most of our dev. team resource is spent on our flagship product - Astah Professional, therefore updating Astah SysML edition has gone behind we're afraid. If you are happy with the features of the sequence diagram in Astah Professional, I'd be happy to provide a free license for it, so please let me know. (although the duration constraint behaviour is same in both editions..)

So are you currently evaluating SysML tools?

Best regards,


Thanks Satomi, I have not used Astah Professional because my first experience with this type of modeling started with SysML. If the features of Astah Professional integrate directly with the SysML software then it would be useful to use the Professional license. If it is a separate program and cannot open the SysML model files I have created with the SysML software, then it may not be of much use. Please contact me about that at the email address I am using here for notifications (or if you don't have access to that info please let me know and I will send an email to support).

Regarding the package diagram, I see that that is possible but it's not clear to me if this is used just to make diagrams that look like package diagrams, or if they actual model the system as done with package diagrams. I haven't worked with these enough to be sure. Also when sharing diagrams with non-Astah users, it is cumbersome to have to explain that some of the BDDs are PKG diagrams. It highlights the fact that I'm using a limited tool to model.

I have been trying to learn SysML for about a year and as any new SysML user will find, there are few tools and some very expensive. I'm also using SysML on an active project with a team outside my organization that is using a more mainstream (expensive) tool that my group can't afford. So I am building a model in Astah that I use to share information with them, and they put it in their model. It becomes difficult to properly describe the model when the tool does not implement the SysML spec in the right way, which is where I'm running into trouble.

Hi mp,

Thanks again for your reply and sharing the context how you are using Astah SysML.

First, Astah Professional and Astah SysML files are not compatible, so I'm afraid that giving you an access to Astah Professional would make you go back and forth between the two apps which would end up being inefficient since you seem to be using other diagrams (BDD, IBD...etc) much. Sorry. (Some of our customers who heavily used Sequence diagrams were okay with this solution in the past, so.)

Regarding the Package diagram, I'll have to say that the former is correct - to make diagrams that look like Package diagrams. It does actually model some - packages, stereotypes, generalizations...etc. However other relations such as ProfileApplication, references won't be modelled - those would be just visuals.

Thank you for choosing Astah SysML, you must've had some hopes up towards our tool when you started out. And I am really sorry that the lack of implementations in Astah SysML is giving you troubles and frustrations. I've asked dev. team and confirm that there is no plan to update Astah SysML any time soon. I am really sorry. If this plan changes, I'll post here to inform you that. (I don't have an access to your email address that you use here.)



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