Choosing a free UML tool

Background

I have decided to write this article for college undergraduate, small sized company that would like to have free UML modeling tool that is required for software design. I believe that comparison is not enough as it is but you need always to specify the context you are doing the comparison for, and usually comparison factors have different weights to each one.

Context

Low budget company or student who would like to have tool for drawing UML diagrams to the latest specs as much as possible, also being able generate documentation for the tool viewable by other colleges or having a viewer for its diagrams. Code generation will be very good option, but mainly sharing the design as images to be able to communicate it to others is the most important.

	Modelio	Papyrus	Astah
Supported UML version	Yes, 2.4.1	Yes, 2.5	2.1 to 2.5 based on user request.
Use-case diagram	Yes	Yes	Yes
Class diagram	Yes	Yes	Yes
Object diagram	Yes	Yes, as variation of class diagram, refer to this forum thread.	Yes
Sequence diagram	Yes	Yes	Yes
Collaboration / Communication diagram	Yes	Yes	Yes
State diagram	Yes	Yes	Yes
Package diagram	Yes, through class diagram.	Yes	Yes
Component diagram	Yes, through class diagram.	Yes	Yes
Activity diagram	Yes	Yes	Yes
Export diagram to image	Yes	Yes	Yes
Publish to Web (Export to HTML)	Yes, free edition Web Model Publisher.	Not by itself, need either modeling gendoc or BIRT, based on this thread. Quite complex.	Yes, professional version
Publish to rtf or doc	Yes, professional edition, Document Publisher, but expensive 400 Euro.	Not by itself, need either modeling gendoc or BIRT, based on this thread. Quite complex.	Yes, professional version
Based on Standard IDE	Eclipse RCP framework	Eclipse	No, seems Java based product only.
UML to code generation (Languages)	Yes (Java)	Yes (Java, C/C++, ADA)	Yes (Java, C++, C#), but professional version only.
Reverse Engineer code to UML	Yes (Java)	Yes (Java)	Yes (Java), but professional version only
Model checking (Pre-defined/Customizable)	-- TODO --	-- TODO --	-- TODO --
Model checking (While saving/On Demand)	-- TODO --	-- TODO --	-- TODO --
XMI version (Import & Export)	Yes, OMG UML 2.1.1 -> 2.4.1 (From Preferences -> XMI)	Yes, 2.1	Yes, but for professional version only
Started since	2009	2008	1999 as JUDE, and renamed to Astah 2009
Release activity	Major release every 1.5 or 2 years Bug fix release: around 4 per year.	1 Major release is planned across 1 year, minor releases are quite few.	No major release since 2009, but most of minor releases has new features, and around 2 - 5 minor releases per year.
Latest release & date	v3.1.2 (2014-05-20)	v1.0.0 (2014-06-25)	v2.8 (2014-02-13)
Has Enterprise version for future upgrade.	Yes	No	Yes
Forum activity	Between low and average	Above average	Between low and average
Extendable and marketplace	Yes	Extendable but not marketplace.	Yes
Integration with Atlassian Confluence	No	No	Yes, for server edition free, not available for cloud
Windows installer	Yes	Yes, eclipse based just as update	Yes
Mac OS installer	Yes, instruction here.	Yes, eclipse based just as update	No
Linux installer	Yes	Yes, eclipse based just as update	No
iPad version	No	No	Yes, iOS 8
Download link	here, around 200 MB	here, around 330 MB for Eclipse Modeling Tools, then papyrus 94 MB.	here, around 60 MB
Youtube channel	ModelioCommunity	Papyrus Eclipse	ChangeVision Astah
General comment	Tool is quite good. Its help is great and search on Internet gets quick answer. Community had a lot of answers to my questions. Require some learning curve for adding and hiding elements.	Documentation is not complete. Tutorial is outdated since 2010. Although download components separately, it took more than 3 hours installing eclipse and Papyrus, even was not responding several minutes. It is quite comprehensive & having lots of features. Very hard from usability perspective. Require longest time learning curve.	Much smaller than other releases. Lightweight tool. Not good interface. Simple in creating attributes, operations.

Conclusion

I have decided to use Modelio for the moment and will keep posting feedback to the page.For anyone viewing this blogpost, take the above table as a base and add whatever factors you would like to have in the tool, and complete the comparison and decide for yourself, I believe the above list contains the best free UML tools as by the time of writing this blogpost.

I'm open for discussion and feedback.

Discarded Products

Product name	Reason for disqualification
Visual Paradigm - community edition	Community is full featured but limited to one diagram per diagram type.
Argo UML	Not maintained since 2011.
BOUML	It became licensed software.
TopCoder UML tool	Last activity in May 2013, after stopping around 3 years.
Gaphor	Only UML 2.0 support.
Dia	It seems not maintained anymore.
NClass	Not maintained since 2010 although its GUI is very good.
yEd	Supports only class diagram& object diagram.
Umbrello	Only UML 2.0 support.
Poseidon for UML community	Only UML 2.0 support.
Star UML 2	Old version has lot of adaptation, but new version which seem complete re-write is still under development. It seems might be very good choice in near future

Comparison References

• Modeling languages: UML tools
• Object by Design: Product by company
• Wikipedia list of UML tools
• Software Talk: Comparison of free UML tool.
• Evaluation of Free UML tools.
• Top 12 Open Source UML tools.