1. A method of rendering a virtual environment, said virtual environment having a virtual model, comprising: identifying a user entering the virtual environment and user context in the virtual model; rendering an output of the virtual model using objects in the virtual model; locating, in associated user memory, previous versions of the objects in the virtual model; identifying differences between the objects in the virtual model and the previous versions of the objects located in the user memory; and rendering a layer of the identified differences on the rendered output of the virtual model by modifying the objects in the virtual model based on user preference, wherein an identified difference is rendered differently than another identified difference according to the user preference and according to type of object.