<s>
In	O
real-time	B-General_Concept
computer	I-General_Concept
graphics	I-General_Concept
,	O
geometry	B-General_Concept
instancing	I-General_Concept
is	O
the	O
practice	O
of	O
rendering	O
multiple	O
copies	O
of	O
the	O
same	O
mesh	B-Algorithm
in	O
a	O
scene	O
at	O
once	O
.	O
</s>
<s>
Although	O
vertex	O
data	O
is	O
duplicated	O
across	O
all	O
instanced	O
meshes	B-Algorithm
,	O
each	O
instance	O
may	O
have	O
other	O
differentiating	O
parameters	O
(	O
such	O
as	O
color	O
,	O
or	O
skeletal	O
animation	O
pose	O
)	O
changed	O
in	O
order	O
to	O
reduce	O
the	O
appearance	O
of	O
repetition	O
.	O
</s>
<s>
Starting	O
in	O
Direct3D	B-Application
version	O
9	O
,	O
Microsoft	O
included	O
support	O
for	O
geometry	B-General_Concept
instancing	I-General_Concept
.	O
</s>
<s>
This	O
method	O
improves	O
the	O
potential	O
runtime	O
performance	O
of	O
rendering	O
instanced	O
geometry	O
by	O
explicitly	O
allowing	O
multiple	O
copies	O
of	O
a	O
mesh	B-Algorithm
to	O
be	O
rendered	O
sequentially	O
by	O
specifying	O
the	O
differentiating	O
parameters	O
for	O
each	O
in	O
a	O
separate	O
stream	O
.	O
</s>
<s>
The	O
same	O
functionality	O
is	O
available	O
in	O
Vulkan	B-Application
core	O
,	O
and	O
the	O
OpenGL	B-Application
core	O
in	O
versions	O
3.1	O
and	O
up	O
but	O
may	O
be	O
accessed	O
in	O
some	O
earlier	O
implementations	O
using	O
the	O
EXT_draw_instanced	O
extension	O
.	O
</s>
<s>
Geometry	B-General_Concept
instancing	I-General_Concept
in	O
Houdini	B-Application
,	O
Maya	B-Language
or	O
other	O
3D	O
packages	O
usually	O
involves	O
mapping	O
a	O
static	O
or	O
pre-animated	O
object	O
or	O
geometry	O
to	O
particles	O
or	O
arbitrary	O
points	O
in	O
space	O
,	O
which	O
can	O
then	O
be	O
rendered	O
by	O
almost	O
any	O
offline	O
renderer	O
.	O
</s>
<s>
Geometry	B-General_Concept
instancing	I-General_Concept
in	O
offline	O
rendering	O
is	O
useful	O
for	O
creating	O
things	O
like	O
swarms	O
of	O
insects	O
,	O
in	O
which	O
each	O
one	O
can	O
be	O
detailed	O
,	O
but	O
still	O
behaves	O
in	O
a	O
realistic	O
way	O
that	O
does	O
not	O
have	O
to	O
be	O
determined	O
by	O
the	O
animator	O
.	O
</s>
<s>
Most	O
packages	O
allow	O
variation	O
of	O
the	O
material	B-General_Concept
or	O
material	B-General_Concept
parameters	O
on	O
a	O
per	O
instance	O
basis	O
,	O
which	O
helps	O
ensure	O
that	O
instances	O
do	O
not	O
appear	O
to	O
be	O
exact	O
copies	O
of	O
each	O
other	O
.	O
</s>
<s>
In	O
Houdini	B-Application
,	O
many	O
object	O
level	O
attributes	O
(	O
e.g.	O
</s>
<s>
In	O
many	O
offline	O
renderers	O
,	O
such	O
as	O
Pixar	O
's	O
PhotoRealistic	B-Application
RenderMan	I-Application
,	O
instancing	O
is	O
achieved	O
by	O
using	O
delayed	O
load	O
render	O
procedurals	O
to	O
only	O
load	O
geometry	O
when	O
the	O
bucket	O
containing	O
the	O
instance	O
is	O
actually	O
being	O
rendered	O
.	O
</s>
<s>
ATI	B-Device
Radeon	I-Device
9500	O
and	O
up	O
(	O
R300	O
GPU	O
or	O
later	O
)	O
.	O
</s>
