1. A method of customizing a model entity presentation based on a presentation policy comprising: creating a plurality of first models according to a second model including elements with information defining a structure and hierarchical arrangement of elements for the first models; associating elements of the second model with a presentation policy model including presentation policies, wherein the presentation policies indicate display characteristics controlling a visual appearance for presented elements; applying the presentation policies to the elements of the first models to generate a corresponding presentation model for each of the first models based on the association between the elements of the second model and the presentation policy model, wherein the corresponding presentation models provide different customized display characteristics for the first models and corresponding model entities created from those first models, and wherein each presentation model associates each of one or more individual elements of a corresponding first model with one or more corresponding display characteristics controlling a visual appearance of a presented element; creating a model entity according to a first model, wherein the model entity includes actual data pertaining to an entity and the first model includes elements with information defining a structure and hierarchical arrangement of elements for the model entity; reading model content from said first model and reading presentation data from said corresponding presentation model; and applying the read model content and presentation data to said model entity to present elements of the model entity including the actual data with a visual appearance in accordance with the associated display characteristics of corresponding individual elements of the first model, wherein at least two elements of the model entity are presented with different display characteristics within a presentation.