Admin : Page créée avec « ====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 cro... »

2018-04-04T13:57:49Z

Page créée avec « ====Definition==== 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 cro... »

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====Definition====
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.<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.

It shall be used to describe a spacecraft geometry in cross section computations for force models.

[[File:facet.PNG|center]]

====Implementation====
This class implements the CrossSectionProvider interface (org.apache.commons.math.geometry.euclidean.threed).<br>
Please refer to the [{{JavaDoc3.3}}/fr/cnes/sirius/patrius/assembly/properties/features/Facet.html Javadoc] for a complete list of public methods.

====Instantiation====
The Facet class is built from its area and normal vector :

<syntaxhighlight lang="java">
Vector3D normalvector = new Vector3D(1.0, 5.6,-3.2);
CrossSectionProvider facet = new Facet(normalvector , 5.0);
</syntaxhighlight>

====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 :

<syntaxhighlight lang="java">
Vector3D incidentialBeam = new Vector3D(7.0,-2.0, 8.0);
double crossSection = facet.getCrossSection(incidentialBeam);
</syntaxhighlight>

The result is not null only if "incidentialBeam " dot product with "normalvector " is negative.

User Manual 3.3 Facets - Historique des versions

Admin : Page créée avec « ====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 cro... »

Admin : Page créée avec « ====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 cro... »