3D scene file created by the jMonkeyEngine (JME) SDK, an application suite used for developing 3D games in Java; saves 3D objects, textures, lighting properties, effects, and other 3D scene information; uses a proprietary binary format required to load the scene into the game at runtime.

J3O files can be created by the SDK's Scene Composer program or by importing a 3D scene that is saved in the OgreXML format. Blender, an open source 3D modeling tool, provides OgreXML export and therefore is a common tool for creating JME scenes. After an OgreXML scene is imported, you can right-click the model and choose "Convert to JME binary" to convert the model into the J3O format. NOTE: You can preview J3O files with SceneViewer, a program included with the jMonkeyEngine SDK.