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2-Dimensional Geometry Plots

We have made a start on implementing 2-dimensional geometry plots—the type of geometry plot made by MCNP. The geometry is shown by color shading and/or black outlines. The default is to outline colored regions; optionally, cells may be outlined. The colors are the Sabrina cell colors. The coloring respects Sabrina’s transparency settings—transparent cells are drawn in the background color. Transparent cells are outlined with the cell outline feature.

The 2-D plots work—sort of—in the geometry testing mode. Depending on the particular geometry error present, a red (or whatever is the error color) will appear at the site of the error. We have also seen cases where the error region is larger than it should be, and where it is drawn in other colors. A geometry error can also cause unexpected colors in different regions of the plot. We have seen a model where spurious geometry errors are reported and extra lines appear when not geometry testing. A scan line in the plot coinciding with a surface causes this problem. Duplicate (2 surface numbers defining the same surface) MCNP surfaces can cause a similar problem. See the discussion in the Geometry Testing section

Most SLICE commands will result in a new plot. The toolbar slice button makes a 2-D plot with the current settings.

The ZOOM and QUERY commands work with the 2-D plots (except for ZOOM ABSOLUTE). We will add the ability to automatically label the 2-D plots with cell, surface, etc. labels.

The 2-D body-based renderer does not draw torii correctly; the surface-based renderer does. The former is used by default with solid body geometry, the latter with surface—usually MCNP—geometry. One can force Sabrina to use the non-default algorithm with the SLICE MODE command, followed by B for the solid body renderer or S for the surface geometry one. In nearly all cases, the surface algorithm shows slices through solid body geometries correctly.

We have encountered one case (JIMS_ROOM.SAB in the example set) that caused Sabrina to prematurely terminate when slicing with the surface algorithm if the surrounding sphere in that model has a very large radius. With a smaller radius, this model is drawn incorrectly with both the surface and body algorithms. We will, of course, attempt to fix this problem.