EVE was designed to integrate engineering analysis data with graphical models representing the spacecraft, aircraft, or other objects being analyzed within a virtual environment. The virtual environment is an interactive time based simulation and analysis environment allowing the user to see the data being analyzed within the context of the operating environment of the craft or crafts.
To accomplish these goals, EVE is built on several components including a solar system model, craft geometry representation models, geometry manipulation tools, dynamics propagators, data input readers, report writers, media capture modules, a data display management system, a navigation module, a time control module, a graphical user interface suite, and object relationship analysis tools.
EVE offers two options to the user for a working environment, a generic base reference frame or that of a solar system environment. When starting with a base reference frame, objects are placed into the scene relative to that reference frame, or to other objects that the user has already added. When starting with a solar system environment, all primary solar system planets and moons are available within the scene. The models of the planets and moons are placed within the scene utilizing the SPICE libraries as a function of the Julian Date. Objects can then be added to the scene as children of the various planets moons, or other objects that the user has already added using one of several provided reference frames such as ecliptic, equatorial, or flight.
Objects within the scene are represented using graphics models. These models can be brought into EVE using one of the many different file formats supported by the OpenSceneGraph API. In addition, EVE supports the use of a DDEX file to define the assembly hierarchical structure of parts. DDEX was developed by AMA and provides a hierarchical description of parts and assemblies that define the overall geometry structure of a craft within EVE, mass information for each part, and joint information. Once brought into EVE, the user can manipulate the crafts at the part, assembly or craft level to move, edit or delete components.
In the scene, object placement is a function of simulation time based on an assigned dynamics model. Dynamics models and the associated propagator position each element in the scene based on the current simulation time. There are several different types of dynamics models that provide for relative placement of an object in the scene. Fixed models provide constant relative placement. Discrete models place objects based on analysis data read from a file. Streaming models place objects based on data read from a network connection. Internal models, such as a Kepler model, place objects based on a well defined algorithm based on a well defined set of starting conditions.
For file operations, EVE provides readers and writers for many different discrete file formats, a reader for the primary EVE mission file, writers for report and log files, a mission package exporter and importer, and leverages OSG for the reading of the geometry files. Except for geometry model files and specific discrete data files, EVE has adopted the use of the XML standard for the specification and storage of data being read into EVE. To support the large amounts of data now being integrated within EVE, a unique hierarchical SAX based reader system has been developed to read in the mission file and associated discrete data.
Once a mission has been created or loaded into EVE, EVE provides numerous components for the exploration and dissemination of the data. The two main exploration modules are the time and navigation modules. To analyze the data and object relationships, EVE contains several analysis tools. These are proximity analysis for studying object to object collision and polygonal level location relationships, line of sight analysis, for studying clear sight between objects and more general distance relationships, and angle analysis for measuring angles between vectors and planes. All analysis data is available within the Data Display Management system for display on the HUD or embedded in the scene, as well as exported using report writing. To disseminate data, EVE provides a Media Export capability for the creation of images and animations.