NClass Alternatives

PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams. The generator can be run anywhere within JVM and integrated with various application such as wiki, text editor, IDE, programming language, documentation generator, and others.

Umbrello is a Unified Modelling Language (UML) modelling tool and code generator. It can create diagrams of software and other systems in the industry-standard UML format, and can also generate code from UML diagrams in a variety of programming languages.

Visual Paradigm for UML (VP-UML) is a UML design tool and UML CASE tool designed to aid software development. VP-UML supports key modeling standards such as Unified Modeling Language (UML) 2.4, SysML, ERD, DFD, BPMN 2.0, ArchiMate 2.0, etc.

StarUML is a program to develop fast, flexible, extensible, featureful, and freely-available UML/MDA platform running on Win32 platform. The goal of the StarUML project is to build a software modeling tool and also platform that is a compelling replacement of commercial UML...

High performance and scalable visual modeling tool for the planning, design and construction of business architectures, software and systems. With customers based in all industries, Sparx Systems is a leading vendor of innovative modeling solutions.

UMLet is an open-source UML tool with a simple user interface: draw UML diagrams fast, export diagrams to eps, pdf, jpg, svg, and clipboard, share diagrams using Eclipse, and create new, custom UML elements.

Astah UML is a UML modeling editor with a user-friendly interface. It allows for the creation of various UML 2.x diagrams and mindmaps. The software includes features such as auto-creation of class diagrams, customizable shortcut keys, and merging project files.

Graphical modelling open source UML2 tool based on Eclipse environment.

Design flowcharts, UML, Venn, and mind map diagrams with customizable templates, varied symbols, shapes, connector styles, overlapping sheet support, and intuitive drag-and-drop editing. Export visuals as images, edit multiple diagrams, and organize complex data visibly.

Lightweight, powerful, easy to use, UML tool

Software Ideas Modeler is a lightweight and powerful CASE tool. It supports UML 2.2 diagrams and a lot of other ones. Software Ideas Modeler is freeware (for non-commercial use). Commercial user may use this software only after buying.

The PlantText tool is an online tool for quickly creating UML (Unified Modeling Language) diagrams. Unlike most tools, PlantText can build diagrams without the use of a mouse because it is based on PlantUML markup language.

Violet is a UML editor with these benefits: Very easy to learn and use. Draws nice-looking diagrams. Completely free. Cross-platform. Violet is intended for developers, students, teachers, and authors who need to produce simple UML diagrams quickly.