Geometry Finders

MaxQ exposes the SPICE Geometry Finder subsystem to Unreal Engine. This subsystem can solve for a large number of geometric conditions.

Action
gfoclt Find occultation
gfposc Observer-Target Vector Coordinate search
gfilum Illumination angle search
gfpa Phase angle search
gfrfov Is ray in FOV?
gfrr Range rate search
gfsep Angular separation search
gfsntc Surface intercept vector coordinate search
gfsubc Subpoint vector coordinate search
gftfov Is target in FOV?

gfstol sets a tolerance value for many of the Geometry Finder blueprint actions.

The SPICE documentation mentions a few “recipes” that can be quickly Blueprinted.

Periapse/Apoapse

To find the unique closest approach of an observer to a target over a specified time window, call gfdist, specifying the

ABSMIN
(absolute minimum) relational operator. To find all of the ‘close approaches’ of an observer to a target over a specified time window use the
LOCMIN
(local minimum) relational operator.
For apoapse events, use the absolute or local maximum operators instead:

ABSMAX
LOCMAX

Spacecraft eclipse
Defining a spacecraft eclipse as the presence of the spacecraft in the shadow created by the Sun and a blocking body, one can observe that eclipses are equivalent to occultations, where the spacecraft is the observer, the Sun is the ‘back’ body, and the blocking body is the ‘front’ body.

Use gfoclt to search for spacecraft eclipses.

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