ASC2G(1)

NAME

asc2g - convert a BRL-CAD geometry database from ASCII to binary form

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SYNOPSIS
DESCRIPTION
DEPRECATION
OPTIONS
EXAMPLES
FILES
SEE ALSO
DIAGNOSTICS
HISTORY
DISCLAIMER
AUTHOR
COPYRIGHT
BUG REPORTS

SYNOPSIS

asc2g [-h] input.asc output.g

asc2g converts a BRL-CAD geometry database from an ASCII format (created by g2asc(1)) to the current binary ".g" format. The tool accepts both the legacy record-based ASCII format and the current Tcl-script-based ASCII format (see HISTORY), automatically detecting which one is present, but always writes the current ("v5") binary geometry database.

Both input.asc and output.g are required, and they must name different files. The conversion is one shot: the entire ASCII file is read and a new binary database is created.

Historically, the binary representation of a geometry database was architecture-dependent. asc2g and g2asc(1) were used to export databases to a portable ASCII form for transfer between systems. While this is no longer necessary for the architecture-independent "v5" binary format, the tools remain useful for migrating legacy "v4" databases, inspecting database contents in a human-readable form, or procedurally generating models via scripts.

DEPRECATION

asc2g is not deprecated and remains a supported part of BRL-CAD. However, its original purpose — producing an architecture-independent form of a geometry database for transfer between machines — has been obsoleted by the machine-independent "v5" binary ".g" format, which can be moved between systems directly. For that reason, asc2g is no longer needed for portability. It is still applicable for importing databases saved with g2asc(1), for building databases from hand-written or generated ASCII scripts, and for round-tripping geometry through a text editor or revision-control system. For upgrading an older database to the current binary version, use dbupgrade(1) instead.

OPTIONS

-h, -?: Print a usage message and exit.

EXAMPLES

Example 1. Round-trip a database through ASCII to migrate it between machines

g2asc model.g model.asc
scp model.asc remote:model.asc
ssh remote "asc2g model.asc model.g"

On the local machine g2asc(1) serializes the binary database to a portable ASCII file, which is copied to a remote host and converted back to a binary ".g" with asc2g. This is the classic workflow for moving geometry between systems, and is also handy for round-tripping a database through a text editor or revision-control system.

Example 2. Build a database from a hand-written or generated script

asc2g model.asc model.g
mged model.g ls

The current ASCII format is a Tcl script of geometry commands (for example put, attr, color, and title), so a database can be produced procedurally by emitting such a script and feeding it to asc2g. The resulting model.g can then be opened with mged(1).

FILES

input.asc is a file previously created using g2asc(1), and output.g is the name of the file where the resulting binary database will be stored.

DIAGNOSTICS

The diagnostics are intended to be self-explanatory. Unrecognized or unsupported records are skipped with a warning written to standard error.

HISTORY

Release 6.0 introduced a new ASCII format. This format is a Tcl script that, when executed by a simplified geometry command interpreter (in essence, a suitably empowered Tcl interpreter), rebuilds the database from which it was derived.

In contrast, the old ASCII format consisted of a sequence of one-line records that corresponded to the old (v4) database format records.

DISCLAIMER

The ASCII representation of BRL-CAD geometry databases is not a fixed format and is allowed to change without deprecation notice. In general, this will not occur any more frequently than the binary geometry database format changes, though both are open specifications. Regardless, the ASCII representation is subject to change without notice and should not be relied upon by external codes. (See HISTORY.)