G-PLY(1)

NAME

g-ply - convert BRL-CAD geometry to a Stanford PLY file

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SYNOPSIS
DESCRIPTION
OPTIONS
EXAMPLES
SEE ALSO
AUTHOR
COPYRIGHT
BUG REPORTS

SYNOPSIS

g-ply [-v] [-s] [-t _type_] [-a _abs_tol_] [-r _rel_tol_] [-n _norm_tol_] [-D _dist_tol_] [-x _rt_debug_] [-X _nmg_debug_] -o _output.ply_ _database.g_ _object_ [_object ..._]

g-ply converts the listed object(s) from a BRL-CAD database.g to the Stanford PLY (Polygon File Format) geometry file named by -o. Each object is tessellated into a faceted mesh by way of the NMG booleans before being written, so any solid, region, or combination that can be evaluated to a triangle mesh may be exported. The output may be ASCII or binary PLY, and by default all requested objects are merged into a single file.

OPTIONS

-o output.ply: Name of the PLY file to write. This option is required. When -s is given, this name is appended as a suffix to each per-object file, which is named object**_output.ply.
-s: Write a separate PLY file for each object instead of merging all objects into a single file.
-t type: Select the PLY encoding. Valid values are asc for ASCII, le for binary little-endian, and be for binary big-endian.
-a abs_tol: Absolute tessellation tolerance in millimeters (the maximum chord distance between the true surface and a facet edge). Setting this clears the relative tolerance. Default is 0.0 (disabled).
-r rel_tol: Relative tessellation tolerance, expressed as a fraction of the bounding-box size of the object. Default is 0.01.
-n norm_tol: Surface normal tessellation tolerance, the maximum angle in degrees between facet normals. Setting this clears the relative tolerance. Default is 0.0 (disabled).
-D dist_tol: Calculational distance tolerance in millimeters used when deciding whether two vertices are coincident. Default is 0.0005.
-x rt_debug: Set the librt debug flag to the given hexadecimal value.
-X nmg_debug: Set the libnmg debug flag to the given hexadecimal value.
-v: Enable verbose output during conversion.
-h, -?: Print the usage message and exit.

EXAMPLES

Example 1. Export a single ASCII PLY for downstream tools

g-ply -t asc -a 0.5 -o widget.ply widget.g body bracket

Tessellates the body and bracket objects from widget.g with a 0.5 mm absolute tolerance, merging them into one human-readable ASCII PLY file that can be inspected or imported into mesh editors and 3D printing slicers.

Example 2. Write one binary mesh per object

g-ply -s -t le -r 0.005 -o parts.ply assembly.g part1 part2 part3

Produces a compact little-endian binary PLY for each of part1, part2, and part3 using a tighter relative tolerance, keeping the individual components in separate files for per-part processing.