Online modeling tools, at the very least, provide a platform, using unified modeling language (UML) to draw and share models online with other users. Complex software systems require unified modeling language tools to provide a semantically and statistically rich visual modeling language that can allow full collaboration. They act as central model repositories for teams which allow for easy and simultaneous modeling collaboration. While unified modeling language is not, in itself, a programming language, it can be used to generate lines code in many different languages by employing UML diagrams. This is because it has a direct correlation with object-oriented analysis and design of software applications. It is, in fact, a combination of several object-oriented notations. Many unified modeling language tools allow users to build highly detailed models, manage project complexity, reverse engineer code, and track all changes, all the while involving the entire team. Diagramming tools, which are only suitable for drawing simple models, lack essential editing features for complex diagrams, including their modification and layout. Unified modeling tools are powerful enough to scale-up and significantly improve the entire software development process. Unified modeling tools are also useful in several other non-software modeling needs. Their applications now go beyond software development to understanding complex process flows such as the ones used in manufacturing plants.