User Manual 3.3 Facets
Definition
A facet is a surface defined by its area and a normal vector, no supposition made of its exact shape.
From those information, it can compute its cross section seen from any incidental vector.
A facet is visibile only from one half-space : the cross section computed is not null only if the dot product with the incidental vector is negative.
It shall be used to describe a spacecraft geometry in cross section computations for force models.
Implementation
This class implements the CrossSectionProvider interface (org.apache.commons.math.geometry.euclidean.threed).
Please refer to the Javadoc for a complete list of public methods.
Instantiation
The Facet class is built from its area and normal vector :
Vector3D normalvector = new Vector3D(1.0, 5.6,-3.2); CrossSectionProvider facet = new Facet(normalvector , 5.0);
Usage
The Facet class proposes basic methods to get its area and normal vector.
It also provides the method getCrossSection (CrossSectionProvider interface), that shall be used this way :
Vector3D incidentialBeam = new Vector3D(7.0,-2.0, 8.0); double crossSection = facet.getCrossSection(incidentialBeam);
The result is not null only if "incidentialBeam " dot product with "normalvector " is negative.
