[ Identification | Description | Input parameters | Links ]

# The `Disc` Component

A geometric shape without effect on neutron, for instrument display purpose.

## Identification

- Site:
- Author: E. Farhi
- Origin: ILL
- Date: June 23rd 2009

## Description

    An inactive geometrical shape, for drawing purposes only.
    It does not propagate neutron, nor interact.
    Shape:
    Geometric shape may be a cylinder, a sphere, a box or any other shape
    box/plate:       xwidth x yheight x zdepth (thickness=0)
    hollow box/plate:xwidth x yheight x zdepth and thickness>0
    cylinder:        radius x yheight (thickness=0)
    hollow cylinder: radius x yheight and thickness>0
    sphere:          radius (yheight=0 thickness=0)
    hollow sphere:   radius and thickness>0 (yheight=0)
    any shape:       geometry=OFF file

    The complex geometry option handles any closed non-convex polyhedra.
    It computes the intersection points of the neutron ray with the object
    transparently, so that it can be used like a regular sample object.
    It supports the OFF and NOFF file format but not COFF (colored faces).
    Such files may be generated from XYZ data using qhull/powercrust, and
    viewed with geomview
    The default size of the object depends of the OFF file data, but its
    bounding box may be resized using xwidth,yheight and zdepth.

    Example: Shape(radius=0.05, yheight=0.1)
    Shape(geometry="socket.off")

## Input parameters

Parameters in boldface are required; the others are optional.

Name | Unit | Description | Default |
radius | m | Outer radius of sample in (x,z) plane | 0 |
xwidth | m | Horiz. dimension of sample (bounding box if off file), as a width | 0 |
yheight | m | Vert. dimension of sample (bounding box if off file), as a height. A sphere shape is used when 0 and radius is set | 0 |
zdepth | m | Depth of sample (bounding box if off file) | 0 |
nx |  |  | 0 |
ny |  |  | 1 |
nz |  |  | 0 |

AT ( | , | , |  | ) RELATIVE |  |
ROTATED ( | , | , |  | ) RELATIVE |

## Links

- Source code for `Disc.comp`.
- Geomview and Object File Format (OFF) <http|://www.geomview.org>
- Powercrust/qhull <http://www.cs.utexas.edu/users/amenta/powercrust>

[ Identification | Description | Input parameters | Links ]