The Forge AlternativesGame Development Tools and other similar apps like The Forge

Torque 3D is a easy-to-use game creation platform. Architected from the ground up for maximum flexibility and performance across a wide range of hardware and built upon the Frontline award-winning Torque Game Engine Advanced, Torque 3D comes equipped with a full suite of tools...

OGRE (Object-Oriented Graphics Rendering Engine) is a scene-oriented, flexible 3D engine written in C++ designed to make it easier and more intuitive for developers to produce applications utilizing hardware-accelerated 3D graphics.

Pygame is a set of Python modules designed for writing video games. Pygame adds functionality on top of the excellent SDL library. This allows you to create fully featured games and multimedia programs in the python language.

ZModeler (or Zanoza Modeler) is a 3D modeling application. It is aimed at modelers who model for computer games such as 18 Wheels of Steel, Grand Theft Auto, Need for Speed, Midtown Madness or similar video games.

Intrinsic is a Vulkan based cross-platform graphics and game engine.

The Grit Game Engine is an MIT-Licensed Open Source Game Engine that is highly scriptable via Lua. It supports huge open world maps and dynamically streams assets from disk. The Grit Game Engine is a community project to build a free game engine (and toolchain) for implementing...

Awakening is a powerful professional real-time 3D solution. With it, you can easily create eye-catching interactive 3D presentations, brief films, games...

Arianne is a multiplayer online games framework and engine to develop turn based and real time games. It provides a simple way of creating games on a portable and robust server architecture. The server is coded in Java and you may use Python for your game description, provides a...

HGE is an easy to use yet powerful hardware accelerated 2D game engine. It is a full featured middleware for all who want to develop commercial quality 2D games rapidly and easily. It covers all imaginable 2D game genres: you could create everything from a simple puzzle to...

MOS is a lightweight cross platform game engine/library, written in modern C++. Some of the included functionality is: 3D mesh rendering, physically based material model, global illumination, particle rendering, text rendering, collision detection, 3D audio playback and asset...

two is an all-purpose c++ app prototyping library, focused towards live graphical apps and games.

The Irrlicht Engine is an open source high performance realtime 3D engine written in C++. It is completely cross-platform, using D3D, OpenGL and its own software renderers, and has all of the state-of-the-art features which can be found in commercial 3d engines.