There are three different parts of DIRSIG which can be queried through the interactive mode. First comes the overall simulation. These attributes are invariant during the course of a DIRSIG run and are thus queried only once. Next comes the interactive prompt. The user supplies a time, solid angle, ray origin, and ray direction. A "solution" is generated from these parameters. The solution as a whole is queried. Finally, a set of queries are applied to every surface intersected by the ray. The user is then returned to the interactive prompt. The process is summarized as follows:
Simulation Level Queries
Interactive Prompt
Solution Level Queries
Surface Level Queries
Back to Interactive Prompt
An example of a simulation-level query is "simatmmodelname", which outputs the name of the atmospheric model being used. An example of a solution-level query is "pathradiance", which outputs the total radiance associated with a query. An example of a surface-level query is "surfaceradiance", which returns the radiance contributed by each individual surface along the query ray's path.
Each DIRSIG element, such as a surface's Material Id or a simulation's Bounding Box, is extracted via a Collector. These in turn are specified in an XML Collector Configuration File.
Interactive Mode can be set to output plaintext, XML or binary. The plaintext output is designed to be human-friendly. The XML output is designed to be easy to parse by computers using off-the-shelf tools. The binary output allows for high-performance interfacing with Interactive Mode.