What are some alternatives?
When comparing OpenSceneGraph and irrlicht, you can also consider the following products
OpenGL - OpenGL is the premier environment for developing portable, interactive 2D and 3D graphics...
Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.
Urho3D - Urho3D is a lightweight, cross-platform rendering and game engine implemented in C++ and released...
Vulkan - Vulkan is a new generation graphics and compute API that provides high-efficiency, cross-platform access to modern GPUs used in a wide variety of devices from PCs and consoles to mobile phones and embedded platforms.
Panda3D - Panda3D is a video game development engine and rendering software. It is developed and maintained by the Carnegie Mellon University Entertainment Technology Center.
Unity - The multiplatform game creation tools for everyone.