<s>
Visual	B-Application
Molecular	I-Application
Dynamics	I-Application
(	O
VMD	O
)	O
is	O
a	O
molecular	O
modelling	O
and	O
visualization	B-Application
computer	B-Application
program	I-Application
.	O
</s>
<s>
Molecular	O
scenes	O
can	O
be	O
exported	O
to	O
external	O
rendering	O
tools	O
such	O
as	O
POV-Ray	B-Application
,	O
RenderMan	B-Application
,	O
Tachyon	B-Application
,	O
Virtual	B-Application
Reality	I-Application
Modeling	I-Application
Language	I-Application
(	O
VRML	B-Application
)	O
,	O
and	O
many	O
others	O
.	O
</s>
<s>
Users	O
can	O
run	O
their	O
own	O
Tcl	B-Operating_System
and	O
Python	B-Language
scripts	I-Language
within	O
VMD	O
as	O
it	O
includes	O
embedded	O
Tcl	B-Operating_System
and	O
Python	B-Language
interpreters	O
.	O
</s>
<s>
VMD	O
runs	O
on	O
Unix	B-Application
,	O
Apple	O
Mac	O
macOS	B-Application
,	O
and	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
The	O
earliest	O
versions	O
of	O
VMD	O
were	O
developed	O
for	O
Silicon	O
Graphics	O
workstations	O
and	O
could	O
also	O
run	O
in	O
a	O
cave	B-General_Concept
automatic	I-General_Concept
virtual	I-General_Concept
environment	I-General_Concept
(	O
CAVE	O
)	O
and	O
communicate	O
with	O
a	O
Nanoscale	O
Molecular	O
Dynamics	O
(	O
NAMD	B-Application
)	O
simulation	O
.	O
</s>
<s>
In	O
1998	O
,	O
John	O
Stone	O
became	O
the	O
main	O
VMD	O
developer	O
,	O
porting	O
VMD	O
to	O
many	O
other	O
Unix	B-Application
operating	I-Application
systems	I-Application
and	O
completing	O
the	O
first	O
full-featured	O
OpenGL	B-Application
version	O
.	O
</s>
<s>
The	O
first	O
version	O
of	O
VMD	O
for	O
the	O
Microsoft	B-Application
Windows	I-Application
platform	O
was	O
released	O
in	O
1999	O
.	O
</s>
<s>
In	O
2001	O
,	O
Justin	O
Gullingsrud	O
,	O
and	O
Paul	O
Grayson	O
,	O
and	O
John	O
Stone	O
added	O
support	O
for	O
haptic	B-Device
feedback	I-Device
devices	O
and	O
further	O
developing	O
the	O
interface	O
between	O
VMD	O
and	O
NAMD	B-Application
for	O
performing	O
interactive	O
molecular	O
dynamics	O
simulations	O
.	O
</s>
<s>
In	O
subsequent	O
developments	O
,	O
Jordi	O
Cohen	O
,	O
Gullingsrud	O
,	O
and	O
Stone	O
entirely	O
rewrote	O
the	O
graphical	O
user	O
interfaces	O
,	O
added	O
built-in	O
support	O
for	O
display	O
and	O
processing	O
of	O
volumetric	O
data	O
,	O
and	O
the	O
use	O
of	O
OpenGL	B-Language
Shading	I-Language
Language	I-Language
.	O
</s>
<s>
VMD	O
can	O
communicate	O
with	O
other	O
programs	O
via	O
Tcl/Tk	B-Application
.	O
</s>
<s>
Here	O
is	O
a	O
list	O
of	O
some	O
VMD	O
plugins	O
developed	O
using	O
Tcl/Tk	B-Application
:	O
</s>
