1. A method for generating a model tree structure for a multiphysics modeling system configured to model combined physical systems having physical quantities represented in terms of partial differential equations, the method being executable on one or more processing units associated with the multiphysics modeling system, the method comprising the acts of: transmitting, for display on one or more display devices, a plurality of selectable physics options for association with at least one of the combined physical systems; receiving, via the one or more processing units, a first input associated with a selection of at least one of the plurality of selectable physics options; transmitting, for display on the one or more display devices, one or more selectable study options for association with the combined physical systems, each transmitted study option corresponding to at least one of the plurality of selectable physics options; receiving, via the one or more processing units, a second input associated with a selection of at least one of the one or more selectable study options; and in response to receiving the second input, generating a model tree structure using the one or more processing units to graphically represent a multiphysics model data structure, the model tree structure including a plurality of user-selectable nodes generated from one or more selected physics options and one or more selected study options, the generated user-selectable nodes including one or more geometry nodes, one or more physics nodes, and one or more study nodes as logically associated branches of the same generated model tree structure such that the plurality of user-selectable nodes include one or more parent nodes and one or more child nodes to the one or more parent nodes, the geometry nodes including user-editable fields for receiving and storing user inputs defining a geometry of the combined physical systems, the user-selectable nodes including fields storing physical quantities for modeling the combined physical systems, at least one of the one or more child nodes including a field storing a modeling operation corresponding to at least one of the selected physics options and at least one of the one or more child nodes including another field storing a modeling operation corresponding to at least one of the selected study options for modeling the combined physical systems, wherein the one or more child nodes include exclusive and non-exclusive child nodes representing modeling operations to generate contributions to equations associated with one or more geometric entities, the exclusive child nodes overriding other nodes and representing contributions that do not coexist with contributions from other nodes on one or more of the geometric entities, the non-exclusive child nodes representing contributions that coexist with other contributions from other non-exclusive nodes.