<s>
BRL-CAD	B-Language
is	O
a	O
constructive	O
solid	O
geometry	O
(	O
CSG	O
)	O
solid	O
modeling	O
computer-aided	B-Application
design	I-Application
(	O
CAD	B-Application
)	O
system	O
.	O
</s>
<s>
It	O
includes	O
an	O
interactive	O
geometry	O
editor	O
,	O
ray	B-Algorithm
tracing	I-Algorithm
support	O
for	O
graphics	O
rendering	O
and	O
geometric	O
analysis	O
,	O
computer	B-Architecture
network	I-Architecture
distributed	O
framebuffer	B-Algorithm
support	O
,	O
scripting	O
,	O
image-processing	O
and	O
signal-processing	O
tools	O
.	O
</s>
<s>
Although	O
BRL-CAD	B-Language
can	O
be	O
used	O
for	O
a	O
variety	O
of	O
engineering	O
and	O
graphics	O
applications	O
,	O
the	O
package	O
's	O
primary	O
purpose	O
continues	O
to	O
be	O
the	O
support	O
of	O
ballistic	O
and	O
electromagnetic	O
analyses	O
.	O
</s>
<s>
In	O
keeping	O
with	O
the	B-Operating_System
Unix	I-Operating_System
philosophy	I-Operating_System
of	O
developing	O
independent	O
tools	O
to	O
perform	O
single	O
,	O
specific	O
tasks	O
and	O
then	O
linking	O
the	O
tools	O
together	O
in	O
a	O
package	O
,	O
BRL-CAD	B-Language
is	O
basically	O
a	O
collection	O
of	O
libraries	O
,	O
tools	O
,	O
and	O
utilities	O
that	O
work	O
together	O
to	O
create	O
,	O
raytrace	B-Algorithm
,	O
and	O
interrogate	O
geometry	O
and	O
manipulate	O
files	O
and	O
data	O
.	O
</s>
<s>
In	O
contrast	O
to	O
many	O
other	O
3D	O
modelling	O
applications	O
,	O
BRL-CAD	B-Language
primarily	O
uses	O
CSG	O
rather	O
than	O
boundary	B-Algorithm
representation	I-Algorithm
.	O
</s>
<s>
This	O
means	O
BRL-CAD	B-Language
can	O
"	O
study	O
physical	O
phenomena	O
such	O
as	O
ballistic	O
penetration	O
and	O
thermal	O
,	O
radiative	O
,	O
neutron	O
,	O
and	O
other	O
types	O
of	O
transport	O
"	O
.	O
</s>
<s>
It	O
does	O
also	O
support	O
boundary	B-Algorithm
representation	I-Algorithm
.	O
</s>
<s>
The	O
BRL-CAD	B-Language
libraries	O
are	O
designed	O
primarily	O
for	O
the	O
geometric	O
modeler	O
who	O
also	O
wants	O
to	O
tinker	O
with	O
software	O
and	O
design	O
custom	O
tools	O
.	O
</s>
<s>
Each	O
library	O
is	O
designed	O
for	O
a	O
specific	O
purpose	O
:	O
creating	O
,	O
editing	O
,	O
and	O
ray	B-Algorithm
tracing	I-Algorithm
geometry	O
,	O
and	O
image	O
handling	O
.	O
</s>
<s>
The	O
application	O
side	O
of	O
BRL-CAD	B-Language
also	O
offers	O
a	O
number	O
of	O
tools	O
and	O
utilities	O
that	O
are	O
primarily	O
concerned	O
with	O
geometric	O
conversion	O
,	O
interrogation	O
,	O
image	O
format	O
conversion	O
,	O
and	O
command-line-oriented	O
image	O
manipulation	O
.	O
</s>
<s>
When	O
no	O
CAD	B-Application
package	O
was	O
found	O
to	O
be	O
adequate	O
for	O
this	O
purpose	O
,	O
BRL	O
software	O
developers	O
–	O
led	O
by	O
Mike	O
Muuss	O
–	O
began	O
assembling	O
a	O
suite	O
of	O
utilities	O
capable	O
of	O
interactively	O
displaying	O
,	O
editing	O
,	O
and	O
interrogating	O
geometric	O
models	O
.	O
</s>
<s>
This	O
suite	O
became	O
known	O
as	O
BRL-CAD	B-Language
.	O
</s>
<s>
Development	O
on	O
BRL-CAD	B-Language
as	O
a	O
package	O
subsequently	O
began	O
in	O
1983	O
;	O
the	O
first	O
public	O
release	O
was	O
made	O
in	O
1984	O
.	O
</s>
<s>
BRL-CAD	B-Language
became	O
an	O
open-source	B-Application
project	O
in	O
December	O
2004	O
.	O
</s>
<s>
The	O
BRL-CAD	B-Language
source	B-General_Concept
code	I-General_Concept
repository	I-General_Concept
is	O
the	O
oldest	O
known	O
public	O
version-controlled	B-Architecture
codebase	O
in	O
the	O
world	O
that	O
's	O
still	O
under	O
active	O
development	O
,	O
dating	O
back	O
to	O
1983-12-16	O
00:10:31	O
UTC	O
.	O
</s>
