<s>
QuickDraw	B-Operating_System
3D	I-Operating_System
,	O
or	O
QD3D	B-Operating_System
for	O
short	O
,	O
is	O
a	O
3D	O
graphics	O
API	B-General_Concept
developed	O
by	O
Apple	O
Inc	O
.	O
(	O
then	O
Apple	O
Computer	O
,	O
Inc	O
.	O
)	O
starting	O
in	O
1995	O
,	O
originally	O
for	O
their	O
Macintosh	B-Device
computers	I-Device
,	O
but	O
delivered	O
as	O
a	O
cross-platform	O
system	O
.	O
</s>
<s>
QD3D	B-Operating_System
was	O
separated	O
into	O
two	O
layers	O
.	O
</s>
<s>
A	O
lower	O
level	O
system	O
known	O
as	O
RAVE	O
(	O
Rendering	O
Acceleration	O
Virtual	O
Engine	O
)	O
provided	O
a	O
hardware	B-Operating_System
abstraction	I-Operating_System
layer	I-Operating_System
with	O
functionality	O
similar	O
to	O
Direct3D	B-Application
or	O
cut-down	O
versions	O
of	O
OpenGL	B-Application
like	O
MiniGL	B-Library
.	O
</s>
<s>
On	O
top	O
of	O
this	O
was	O
an	O
object-oriented	O
scene	B-Data_Structure
graph	I-Data_Structure
system	O
,	O
QD3D	B-Operating_System
proper	O
,	O
which	O
handled	O
model	O
loading	O
and	O
manipulation	O
at	O
a	O
level	O
similar	O
to	O
OpenGL++	B-Library
.	O
</s>
<s>
The	O
system	O
also	O
supplied	O
a	O
number	O
of	O
high-level	O
utilities	O
for	O
file	O
format	O
conversion	O
,	O
and	O
a	O
standard	O
viewer	O
application	O
for	O
the	O
Mac	B-Device
OS	O
.	O
</s>
<s>
QD3D	B-Operating_System
had	O
little	O
impact	O
in	O
the	O
computer	O
market	O
,	O
both	O
as	O
a	O
result	O
of	O
Apple	O
's	O
beleaguered	O
position	O
in	O
the	O
mid-1990s	O
,	O
as	O
well	O
as	O
several	O
fateful	O
decisions	O
made	O
by	O
the	O
design	O
team	O
about	O
future	O
changes	O
in	O
the	O
3D	O
hardware	O
market	O
that	O
did	O
not	O
come	O
true	O
.	O
</s>
<s>
Apple	O
abandoned	O
work	O
on	O
QD3D	B-Operating_System
after	O
Steve	O
Jobs	O
took	O
over	O
in	O
1998	O
,	O
and	O
announced	O
that	O
future	O
3D	O
support	O
on	O
Mac	B-Device
OS	O
would	O
be	O
based	O
on	O
OpenGL	B-Application
.	O
</s>
<s>
The	O
canonical	O
3D	O
API	B-General_Concept
of	O
the	O
1990s	O
was	O
OpenGL	B-Application
.	O
</s>
<s>
This	O
had	O
been	O
written	O
by	O
SGI	O
and	O
initially	O
closely	O
matched	O
the	O
capabilities	O
of	O
their	O
workstation	B-Device
systems	O
,	O
operating	O
as	O
a	O
hardware	B-Operating_System
abstraction	I-Operating_System
layer	I-Operating_System
.	O
</s>
<s>
The	O
OpenGL	B-Application
API	B-General_Concept
consisted	O
mostly	O
of	O
state-setting	O
instructions	O
for	O
setting	O
up	O
drawing	O
modes	O
like	O
the	O
paint	O
color	O
or	O
camera	O
position	O
,	O
and	O
system	O
for	O
sending	O
geometry	O
into	O
the	O
system	O
,	O
normally	O
as	O
meshes	O
of	O
triangles	O
.	O
</s>
<s>
OpenGL	B-Application
lacked	O
many	O
features	O
that	O
are	O
needed	O
to	O
produce	O
a	O
complete	O
3D	O
program	O
.	O
</s>
<s>
A	O
number	O
of	O
efforts	O
started	O
to	O
provide	O
standardized	O
higher	O
level	O
APIs	B-General_Concept
,	O
like	O
OpenGL++	B-Library
and	O
(	O
later	O
)	O
Fahrenheit	B-Library
,	O
which	O
handled	O
many	O
of	O
the	O
more	O
common	O
bookkeeping	O
tasks	O
like	O
loading	O
geometry	O
from	O
files	O
and	O
providing	O
a	O
display	O
.	O
</s>
<s>
These	O
standardized	O
scene	B-Data_Structure
graph	I-Data_Structure
systems	O
meant	O
the	O
programmer	O
only	O
had	O
to	O
provide	O
the	O
GUI	O
for	O
the	O
program	O
.	O
</s>
<s>
While	O
OpenGL	B-Application
is	O
mostly	O
low-level	O
,	O
it	O
did	O
include	O
some	O
higher-level	O
concepts	O
that	O
were	O
only	O
really	O
used	O
on	O
SGI	O
systems	O
.	O
</s>
<s>
This	O
led	O
to	O
another	O
series	O
of	O
APIs	B-General_Concept
that	O
removed	O
these	O
features	O
to	O
make	O
it	O
easier	O
to	O
implement	O
on	O
common	O
hardware	O
.	O
</s>
<s>
The	O
best	O
known	O
of	O
these	O
is	O
MiniGL	B-Library
,	O
which	O
is	O
not	O
a	O
separate	O
API	B-General_Concept
,	O
but	O
simply	O
a	O
list	O
of	O
those	O
functions	O
in	O
OpenGL	B-Application
that	O
are	O
guaranteed	O
to	O
be	O
supported	O
across	O
all	O
hardware	O
,	O
thus	O
ensuring	O
that	O
a	O
program	O
limiting	O
itself	O
to	O
those	O
calls	O
will	O
run	O
with	O
maximum	O
performance	O
.	O
</s>
<s>
QD3D	B-Operating_System
was	O
designed	O
from	O
the	O
start	O
to	O
operate	O
on	O
computers	O
with	O
considerably	O
less	O
power	O
than	O
workstations	B-Device
.	O
</s>
<s>
This	O
led	O
to	O
a	O
concerted	O
effort	O
to	O
cleanly	O
separate	O
the	O
upper	O
and	O
lower	O
layers	O
of	O
the	O
API	B-General_Concept
,	O
with	O
the	O
lower-level	O
RAVE	O
system	O
being	O
closer	O
to	O
MiniGL	B-Library
from	O
the	O
start	O
.	O
</s>
<s>
This	O
had	O
the	O
advantage	O
of	O
providing	O
a	O
clean	O
and	O
minimal	O
API	B-General_Concept
that	O
could	O
be	O
more	O
easily	O
ported	O
to	O
different	O
hardware	O
.	O
</s>
<s>
Since	O
only	O
RAVE	O
needed	O
to	O
be	O
ported	O
,	O
the	O
upper	O
layer	O
APIs	B-General_Concept
could	O
be	O
made	O
as	O
complex	O
as	O
desired	O
,	O
and	O
the	O
QD3D	B-Operating_System
system	O
included	O
a	O
complete	O
scene	B-Data_Structure
graph	I-Data_Structure
,	O
a	O
standardized	O
model	O
file	O
format	O
,	O
3DMF	B-Operating_System
,	O
and	O
even	O
basic	O
GUI	O
objects	O
that	O
utilized	O
them	O
.	O
</s>
<s>
To	O
write	O
a	O
simple	O
application	O
in	O
QD3D	B-Operating_System
,	O
the	O
programmer	O
only	O
had	O
to	O
include	O
a	O
few	O
libraries	O
and	O
then	O
place	O
the	O
GUI	O
elements	O
in	O
their	O
program	O
using	O
ResEdit	B-Operating_System
or	O
similar	O
tools	O
.	O
</s>
<s>
The	O
QD3D	B-Operating_System
API	B-General_Concept
was	O
an	O
object-like	O
system	O
based	O
on	O
pure-C	O
code	O
.	O
</s>
<s>
Objects	O
knew	O
all	O
the	O
drawing	O
state	O
they	O
needed	O
,	O
thereby	O
eliminating	O
code	O
that	O
would	O
normally	O
be	O
needed	O
when	O
developing	O
under	O
OpenGL	B-Application
.	O
</s>
<s>
On	O
the	O
downside	O
,	O
QD3D	B-Operating_System
's	O
layering	O
introduced	O
performance	O
issues	O
.	O
</s>
<s>
Another	O
area	O
of	O
concern	O
is	O
that	O
the	O
scene	B-Data_Structure
graph	I-Data_Structure
was	O
hidden	O
from	O
view	O
,	O
and	O
considerable	O
improvements	O
in	O
rendering	O
performance	O
can	O
be	O
made	O
by	O
carefully	O
"	O
culling	O
"	O
the	O
graph	O
to	O
remove	O
those	O
objects	O
that	O
are	O
not	O
in	O
view	O
.	O
</s>
<s>
Although	O
later	O
releases	O
of	O
QD3D	B-Operating_System
gained	O
the	O
ability	O
to	O
automatically	O
perform	O
visibility	O
culling	O
(	O
based	O
on	O
the	O
grouping	O
of	O
objects	O
in	O
the	O
scene	B-Data_Structure
graph	I-Data_Structure
)	O
,	O
OpenGL	B-Application
's	O
lack	O
of	O
support	O
for	O
this	O
feature	O
typically	O
forced	O
developers	O
to	O
implement	O
it	O
from	O
the	O
start	O
.	O
</s>
<s>
Although	O
RAVE	O
was	O
designed	O
to	O
be	O
cross-platform	O
,	O
only	O
hardware	O
developers	O
which	O
supported	O
Mac	B-Device
(	O
ATI	O
,	O
NVIDIA	O
,	O
and	O
3dfx	O
)	O
produced	O
drivers	O
for	O
it	O
.	O
</s>
<s>
This	O
left	O
any	O
comparison	O
between	O
QD3D	B-Operating_System
and	O
alternative	O
APIs	B-General_Concept
one-sided	O
,	O
as	O
outside	O
of	O
the	O
Mac	B-Device
QD3D	B-Operating_System
was	O
forced	O
to	O
fall	O
back	O
to	O
a	O
software	O
RAVE	O
implementation	O
.	O
</s>
<s>
As	O
OpenGL	B-Application
gained	O
traction	O
on	O
Windows	O
(	O
often	O
credited	O
to	O
id	O
Software	O
,	O
who	O
championed	O
the	O
API	B-General_Concept
over	O
D3D	O
)	O
,	O
hardware	O
developers	O
were	O
increasingly	O
designing	O
future	O
hardware	O
against	O
the	O
future	O
feature	O
set	O
planned	O
for	O
Microsoft	O
's	O
D3D	O
.	O
</s>
<s>
Through	O
its	O
extension	O
mechanism	O
OpenGL	B-Application
was	O
able	O
to	O
track	O
these	O
changes	O
relatively	O
easily	O
,	O
while	O
RAVE	O
's	O
feature	O
set	O
remained	O
relatively	O
fixed	O
.	O
</s>
<s>
At	O
the	O
Macworld	O
Expo	O
in	O
January	O
1999	O
,	O
Apple	O
announced	O
that	O
neither	O
QuickDraw	B-Operating_System
3D	I-Operating_System
nor	O
RAVE	O
would	O
be	O
included	O
in	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
.	O
</s>
<s>
The	O
company	O
laid	O
off	O
the	O
development	O
staff	O
in	O
June	O
1999	O
,	O
replacing	O
the	O
in-house	O
technology	O
with	O
OpenGL	B-Application
after	O
buying	O
a	O
Mac	B-Device
implementation	O
and	O
key	O
staff	O
from	O
Conix	O
Enterprises	O
.	O
</s>
<s>
After	O
Apple	O
withdrew	O
support	O
for	O
QD3D	B-Operating_System
,	O
an	O
open	B-License
source	I-License
implementation	O
of	O
the	O
QD3D	B-Operating_System
API	B-General_Concept
was	O
developed	O
externally	O
.	O
</s>
<s>
Known	O
as	O
Quesa	O
,	O
this	O
implementation	O
combines	O
QD3D	B-Operating_System
's	O
higher	O
level	O
concepts	O
with	O
an	O
OpenGL	B-Application
renderer	O
.	O
</s>
<s>
As	O
well	O
as	O
cross-platform	O
hardware	O
acceleration	O
,	O
this	O
library	O
also	O
allows	O
the	O
use	O
of	O
the	O
QD3D	B-Operating_System
API	B-General_Concept
on	O
platforms	O
never	O
supported	O
by	O
Apple	O
(	O
such	O
as	O
Linux	B-Application
)	O
.	O
</s>
