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McStas: Shape Component

[ Identification | Description | Input parameters | Output parameters | Links ]

The Shape Component

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


  • Author: E. Farhi
  • Origin: ILL
  • Date: June 23rd 2009
  • Version:(Unknown)
  • Modification history:
    • E. Farhi, based on Incoherent


An inactive geometrical shape, for drawing purposes only.
It does not propagate neutron, nor interact.
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)

Input parameters

Parameters in boldface are required; the others are optional.
Name Unit Description Default
geometry str Name of an Object File Format (OFF) file for complex geometry. The OFF file may be generated from XYZ coordinates using qhull/powercrust 0
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 bounding box if off file [m] Depth of sample 0
thickness m Thickness of hollow sample 0

Output parameters

Name Unit Description Default


  • Source code for Shape.comp.
  • Geomview and Object File Format (OFF)
  • Powercrust/qhull

[ Identification | Description | Input parameters | Output parameters | Links ]

Generated automatically by McDoc, Peter Willendrup <> / Wed Jan 12 15:13:31 2022

Last Modified: Wednesday, 12-Jan-2022 16:13:31 CET
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