The Models node allows you to configure your simulation by specifying which physical models to apply and to define options related to those models. Once a model is selected from this tree (that is, using the check boxes), further configuration options are available to specify any necessary model parameters. For example, when Spray Model is selected, icons become available for configuring injectors, and under injectors are nozzles and injection events. Items under the Models node include Chemistry, Transport, Spray Model, Spark Ignition, Crevice Model, and Soot Model.