Umbrello is a KDE based software for creating UML diagrams in standard format. Try some of them and choose the one which suits you best. Here are some of the most popular free and open source UML Modelling softwares that you can use with Ubuntu or other Linux distro, some of them are cross-platform i.e also available for Windows and Mac OS. There are various tools available such as IBM Rational Rose, for drawing UML diagrams but in this post you are going to know about some open source modelling tools, that you can use on your Linux based Operating systems e.g Ubuntu 11.04 (Natty Narwhal) /11.10 (Oneiric Ocelot, the code name of upcoming version)/ or older versions such as 10.10/10.04 LTS…, Linux Mint, Fedora, OpenSuse etc.

UML diagrams represents – Static as well as Dynamic views of a system, by using UML tools you can draw – class diagrams, activity diagrams, sequence diagrams, use case diagrams etc. In fact, the UML diagrams makes coding part easier in complex systems, so the time you would spent in drawing will save you a lot of time (later, during development/implementation phase).

UML, created by OMG (Object Management Group), has now become the standard approach to software modelling. It is typically used in the design phase of object oriented software development process, to express the thought in graphical representation, to visualize the system and so on. Unified Modelling Language (UML) is a modelling languages.

Sequence diagram online tool uml 2.5