Files with the LWO extension are used, among others, by the id Tech 4 video game engine, also known as Doom 3 Engine. However, these files are created in a 3D modeling program called LightWave 3D. These files store a structure of 3D objects called a mesh. The surface of such an object is composed of a certain number of polygons. In addition, such objects can have attributes such as color, texture, transparency, etc.

LightWave 3D was developed by NewTek, Inc. The LWO format can also be exported by Foundry Modo.