A truncated pyramid (frustum) with trigonal base.
Pyramid3(L, H, alpha)
Parameters:
Constraint:
The orthographic projection also shows the angle
As for any other Form factor.
Class Pyramid3 inherits from the interface class IFormFactor .
Form factor computation is based on the generic form factor of a polyhedron provided by libformfactor .
Volume has been validated
against
More special:
Scattering by uncorrelated, oriented pyramids for horizontal incidence. Rotation around
Generated by Examples/ff/Pyramid3.py .
Was incorrectly named “Tetrahedron” up to BornAgain 1.19.
Corresponds to “Tetrahedron” in IsGISAXS [manual, Eq. 2.29;
Renaud 2009, Eq. 220] and “Truncated tetrahedron” in FitGISAXS [Babonneau 2013]. In BornAgain 1.6, redefined to let the
Up to BornAgain 1.5, we computed the form factor by numeric integration, as in IsGISAXS. Since BornAgain 1.6 higher speed and accuracy are achieved by using the generic form factor of a polyhedron [Wuttke 2021] with series expansions near singularities.