The emergence of cheaper technologies for immersive environments has increased considerably the interest on applications of Virtual Reality (VR). However, currently available VR frameworks force user applications to be developed specifically for them. This increases the cost of converting an existing graphical application to virtual reality environments. This paper proposes a new framework, the LVRL (Lightweight Virtual Reality Libraries), which allows both creation and conversion of existing applications to VR without changing the structure of the application. The LVRL main objective is to provide a minimalist programming interface and non intrusive allowing the development of VR applications by non VR developers. This article describes the architecture of LVRL, its features, usage and the benefits obtained by the applications that use it. © 2012 IEEE.