User Manual 3.4.1 Facets : Différence entre versions
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====Definition==== | ====Definition==== | ||
| − | A facet is a surface defined by its area and a normal vector, no supposition made of its exact shape. | + | A facet is a surface defined by its area and a normal vector, no supposition made of its exact shape.<br> |
| − | From those information, it can compute its cross section seen from any incidental vector. | + | From those information, it can compute its cross section seen from any incidental vector.<br> |
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. | 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. | ||
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====Implementation==== | ====Implementation==== | ||
| − | This class implements the CrossSectionProvider interface (org.apache.commons.math.geometry.euclidean.threed). | + | This class implements the CrossSectionProvider interface (org.apache.commons.math.geometry.euclidean.threed).<br> |
| − | Please refer to the [{{ | + | Please refer to the [{{JavaDoc3.4.1}}/fr/cnes/sirius/patrius/assembly/properties/features/Facet.html Javadoc] for a complete list of public methods. |
====Instantiation==== | ====Instantiation==== | ||
Version actuelle en date du 4 avril 2018 à 13:57
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.
