Shapes are objects that can pick random points within a certain area or volume. More...
Modules | |
| Surface Shapes | |
| Surface shapes are shapes that support the getPointSourceDirection() method. | |
Classes | |
| class | EGS_BaseShape |
| Base shape class. All shapes in the EGSnrc C++ class library are derived from EGS_BaseShape. More... | |
| class | EGS_SurfaceShape |
| A surface shape. More... | |
| class | EGS_PointShape |
| A point shape. This is the simplest shape possible: it simply always returns the same point. More... | |
| class | EGS_BoxShape |
| A box shape. More... | |
| class | EGS_SphereShape |
| A sphere shape. More... | |
| class | EGS_CylinderShape |
| A cylinder shape. More... | |
| class | EGS_CircleShape |
| A circle shape. More... | |
| class | EGS_CirclePerpendicularShape |
| A circle shape perpendicular to source particles. More... | |
| class | EGS_EllipseShape |
| An elliptical shape. More... | |
| class | EGS_ExtendedShape |
| An extended shape. More... | |
| class | EGS_GaussianShape |
| A Gaussian shape. More... | |
| class | EGS_LineShape |
| A line shape. More... | |
| class | EGS_TriangleShape |
| A triangular shape. More... | |
| class | EGS_PolygonShape |
| A polygon shape. More... | |
| class | EGS_RectangleShape |
| A rectangular shape. More... | |
| class | EGS_RectangularRing |
| A "rectangular ring". More... | |
| class | EGS_ShapeCollection |
| A shape collection. More... | |
| class | EGS_VoxelizedShape |
| A "voxelized shape". More... | |
Detailed Description
Shapes are objects that can pick random points within a certain area or volume.
Many of the sources used in the standard set of EGSnrc user codes and provided as classes derived from EGS_BaseSimpleSource determine the direction and position of a particle from the following generic algorithm:
- Set the position
from either a fixed position or a random position picked within a certain region in space. - Pick a random position
in some other region in space and determine the direction as 
.
This algorithm does not depend on the details of selecting the random positions and is therefore ideally implemented using abstract objects that are able to deliver a random position. Such objects are called 'shapes' in the egspp framework. All concrete shapes available in the EGSnrc C++ class library are derived from the abstract EGS_BaseShape class, which specifies the interface to shape objects. The most important method defined is getPoint() , which takes a random number generator as input and delivers a random 3D vector. All shapes can have an affine transformation 
, which is applied to the random position before returning it to the caller.
A large number of shapes is provided with the egspp package. Most shapes are implemented as small DSOs, which are loaded dynamically as needed. Such shapes require the library key to be present in their definition in the input file. A few of the most frequently used shapes are compiled into egspp and therefore require a type key instead of a library key.
