PATCH-G(1)

NAME

patch-g - convert a preprocessed FASTGEN target description into a BRL-CAD database

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SYNOPSIS
DESCRIPTION
OPTIONS
EXAMPLES
SEE ALSO
AUTHOR
COPYRIGHT
BUG REPORTS

SYNOPSIS

patch-g [options] model.g

patch-g converts FASTGEN target geometry into a BRL-CAD .g database. FASTGEN is a modeling system used to create military target descriptions, whose primitives (triangles in volume and plate mode, wedges, spheres, boxes, cylinders, and rods) are reproduced by patch-g as NMG solids, BoTs (polysolids), or ARB6 solids.

The FASTGEN file must first be passed through the rpatch(1) preprocessor, which produces the intermediate ".rp" file that patch-g consumes. The preprocessed input is read from standard input unless the -f option names a file, and the resulting geometry is written to the model.g database named as the sole positional argument.

By default solids are written as NMG primitives; -p selects BoT (polysolid) output, and -6 converts plate-mode triangles to ARB6 solids. Components are grouped into regions with a fixed number of unions each (see -T and -A for the tolerances controlling vertex fusing and face merging). Diagnostic messages are emitted when geometry cannot be converted; the -d option raises the verbosity, with higher levels producing more output.

OPTIONS

-f fastgen.rp: Read the pre-processed (through rpatch(1)) FASTGEN file instead of standard input.
-n: Process volume mode components as plate mode.
-u number: Number of union operations per region (default 5).
-c "x y z": Center of the object, in inches, used for some plate-mode surface normal calculations. The quotation marks are required to group the three values.
-t title: Title for the output database (default "patch-g conversion").
-o object_name: Name of the top-level object, containing no spaces (default "all").
-p: Write volume- and plate-mode components as BoT (polysolid) primitives rather than NMG solids.
-6: Process plate-mode triangles as ARB6 solids (overrides -p for triangles).
-i group.file: Read group label (region naming) information from the named file.
-m mat.file: Read material property information from the named file.
-j jtype.file: Read component JTYPE thickness from the named text file (units: in) for components that have no/zero thickness.
-r: Reverse the surface normals for plate-mode triangles.
-d level: Set the debug (diagnostic verbosity) level. Higher numbers produce more diagnostic output (levels above 3 also write intermediate NMG solids to the database).
-x flag: Set the librt debugging flags (hexadecimal).
-X flag: Set the NMG (librt) debugging flags (hexadecimal).
-T distance: Vertex tolerance distance, in inches. Two vertices closer together than this are treated as the same vertex.
-A tolerance: Perpendicularity tolerance, given as the cosine of an angle (0.0 through 1.0). Two unit vectors whose dot product is less than this value are considered perpendicular.

EXAMPLES

Example 1. Convert a FASTGEN target to a polysolid BRL-CAD database

rpatch < tank.fastgen > tank.rp
patch-g -p -f tank.rp -t "M1 Tank" -o tank tank.g

First rpatch(1) preprocesses the raw FASTGEN file into the intermediate tank.rp. patch-g then converts it, writing BoT (polysolid) geometry under a top-level group named tank, with a database title of "M1 Tank", into the new tank.g database that can be opened in mged(1).