"DOORS/Analyst looks great. For requirements gathering and specification we typically model use cases and write the textual descriptions and non-functional requirements in separate tools. To be able to do this within one integrated tool environment would be a great leap forward in reducing the non-productive requirements work." SaabTech

What is Visual Modeling?

Visual modeling is fundamentally the activity of drawing diagrams and pictures to describe something: the structure of a system, a sequence of events, relations between entities, etc. With visual modeling, furthermore, we usually mean that certain regulations are put on how the drawings can be designed - a certain degree of formality is imposed, which means that the drawing activities will result in something that follows at least a basic set of rules or standards. This in turn means that the end result is more than just a "drawing" - it is a model.

There are many advantages to this approach. First, it makes it possible to build tools that will help the user when designing models, providing built-in syntactic and semantic checks that guide the user in finding inconsistencies and gaps in the drawings, and making sure that a change in one part of the drawing is automatically reflected in other parts where it is relevant. Second, with visual modeling, a set of agreed standards is usually applied which means that a common visual language is established which makes it easier for other people to interpret the model, leaving less room for misunderstandings. Third, with modeling using a formal visual language it is possible to design tools that can actually simulate the models to demonstrate and understand behavior.

	Use cases provide an efficient way to capture typical user scenarios – Use case image created in DOORS/Analyst.
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Some tools, such as TAU Generation2 and the new DOORS/Analyst offer the user a choice: either draw with relaxed rules and little demands for formality, or put in the effort to create a complete detailed model. DOORS/Analyst offers a particularly liberal approach since it does not impose any demands that the drawings must be part of one, coherent model. An additional flexibility is introduced in these tools through the support of user-defined pictures and diagrams which make it easy to create drawings that reflect real-life concepts and systems.

The most popular visual modeling language is UML. This language was first standardized in 1997, and was recently released in a major updated version: UML 2.0. With UML 2.0, which is the language supported in TAU and DOORS/Analyst, the language has been much improved for visual modeling of complex systems. With UML 2.0 it is easy to describe system architectures, to model typical use cases and to describe sequences of events - to name but a few.

Find out more by downloading the white paper
"Requirements-driven and Model-driven Development: Combining the Benefits for Systems Engineering"