ASC-NMG
1
BRL-CAD
BRL-CAD

# asc-nmg

ascii-to-NMG converter

      asc-nmg
        ascii_file
        nmg.g

## DESCRIPTION

asc-nmg converts the specified ascii_file (not a .asc geometry database) to a binary BRL-CAD nmg.g geometry database file containing NMG objects. The ascii_file is expected to contain lines of the following forms:

To start a new outer loop for a face:

    	l

To start a new "hole" loop in the current face:

    	l hole

To indicate a vertex in the current loop:

    	v# x y z

where # is the vertex number and x, y, and z are the coordinates of that vertex.

To extrude a face:

    	e x y z

where x, y, and z compose the extrusion vector for the face.

If an extrusion vector is specified, then the first face in the NMG objects list of faces will be extruded. This is intended for cases where only one face is described and then extruded to form a solid. Supplying an extrusion vector when more than one face is described may produce erroneous results. A solid may be built by extruding a face or by building enough faces to produce a closed shell. Each execution of `asc-nmg` will produce a single NMG object.

## EXAMPLE

If the file ascii_file contains the following:

    l
    	e	-1 0 0
    	v0	1 -1 -1
    	v1	1 1 -1
    	v2	1 1 0
    	v3	1 0 0
    	v4	1 0 1
    	v5	1 -1 1

Then, the command:

    $ asc-nmg ascii_file sample.g

will produce an 'L'-shaped NMG solid to the sample.g database file.

## DIAGNOSTICS

Error messages are intended to be self-explanatory.

## AUTHOR

BRL-CAD Team

## COPYRIGHT

This software is Copyright (c) 1994-2013 by the United States Government as represented by U.S. Army Research Laboratory.

## BUG REPORTS

Reports of bugs or problems should be submitted via electronic mail to <devs@brlcad.org>.