PENELOPE 2003 - OECD Nuclear Energy Agency

5.6. Debugging and viewing the geometry 171
Table 5.2: One-character commands of the gview2d geometry viewer.
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+ x --> change window orientation, x-axis, +
+ y --> change window orientation, y-axis, +
+ z --> change window orientation, z-axis, +
+ r,right --> shift right, l,left --> shift left, +
+ u,up --> shift up, d,down --> shift down, +
+ f,pgup --> shift front, b,pgdn --> shift back, +
+ i,+ --> zoom in, o,- --> zoom out, +
+ 1 --> actual size, h,? --> help, +
+ blank, enter --> repeat last command, q --> quit. +
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When running the gview2d program, you will be asked to give the path+name of
the geometry definition file and the coordinates (XC,YC,ZC) of the centre of the window
(relative to the laboratory frame) in cm. The window may appear black (the colour for
void regions) if no material bodies are intersected. In this case, use the one-character
viewer commands to reach the bodies or, more conveniently, start again and place the
window centre near or within a filled body.
gview3d generates three-dimensional pictures of the geometry by using a simple raytracing
algorithm, with the source light and the camera at the same position. Bodies
are displayed with the same colour code used by gview2d and the intensity of each
pixel is determined by the angle between the vision line and the normal to the limiting
surface. This method does not produce shadows and disregards light diffusion, but
makes fairly realistic three-dimensional images. The camera is assumed to be outside
the system (placing the camera inside a body would stop the program). To reveal the
inner structure of the system, the program can eliminate a wedge (limited by two vertical
planes that intersect in the z-axis). The position and size of the system can be modified
by means of one-character commands entered from the graphics window. The command
keys and actions are similar to those of gview2d. It is worth noting that gview3d
generates the image pixel by pixel, whereas gview2d does it by drawing straight lines
on the window; as a result, gview2d is much faster.
gview2d and gview3d produce an output file named GEOMETRY.REP (which is
generated by subroutine GEOMIN) in the working directory. The programs are stopped
either when an input format is incorrect (reading error) or when a clear inconsistency in
the definition file is found (e.g. when the element that is being defined and the furnished
information do not match). The wrong datum appears in the last printed lines of the
GEOMETRY.REP file, usually in the last one. Error messages are also written on that file,
so that the identification of inconsistencies is normally very easy. When the structure of
the input file is correct, the codes do not stop and the geometry is displayed for further
analysis. Most of the possible errors in the input file can only be revealed by direct
inspection of the images generated by gview2d and gview3d.
The file GEOMETRY.REP is a duplicate of the input definition file. The only differ-