<s>
A	O
3D	B-Algorithm
projection	I-Algorithm
(	O
or	O
graphical	B-Algorithm
projection	I-Algorithm
)	O
is	O
a	O
design	O
technique	O
used	O
to	O
display	O
a	O
three-dimensional	O
(	O
3D	O
)	O
object	O
on	O
a	O
two-dimensional	O
(	O
2D	O
)	O
surface	O
.	O
</s>
<s>
These	O
projections	B-Application
rely	O
on	O
visual	B-Architecture
perspective	I-Architecture
and	O
aspect	O
analysis	O
to	O
project	B-General_Concept
a	O
complex	O
object	O
for	O
viewing	O
capability	O
on	O
a	O
simpler	O
plane	O
.	O
</s>
<s>
3D	B-Algorithm
projections	I-Algorithm
use	O
the	O
primary	O
qualities	O
of	O
an	O
object	O
's	O
basic	O
shape	O
to	O
create	O
a	O
map	O
of	O
points	O
,	O
that	O
are	O
then	O
connected	O
to	O
one	O
another	O
to	O
create	O
a	O
visual	O
element	O
.	O
</s>
<s>
As	O
such	O
,	O
graphical	B-Algorithm
projections	I-Algorithm
are	O
a	O
commonly	O
used	O
design	O
element	O
;	O
notably	O
,	O
in	O
engineering	B-Architecture
drawing	I-Architecture
,	O
drafting	B-Application
,	O
and	O
computer	O
graphics	O
.	O
</s>
<s>
Projections	B-Application
can	O
be	O
calculated	O
through	O
employment	O
of	O
mathematical	O
analysis	O
and	O
formulae	O
,	O
or	O
by	O
using	O
various	O
geometric	O
and	O
optical	O
techniques	O
.	O
</s>
<s>
Projection	B-Application
is	O
achieved	O
by	O
the	O
use	O
of	O
imaginary	O
"	O
projectors	O
"	O
;	O
the	O
projected	O
,	O
mental	O
image	O
becomes	O
the	O
technician	O
's	O
vision	O
of	O
the	O
desired	O
,	O
finished	O
picture	O
.	O
</s>
<s>
Methods	O
provide	O
a	O
uniform	O
imaging	O
procedure	O
among	O
people	O
trained	O
in	O
technical	B-Application
graphics	I-Application
(	O
mechanical	O
drawing	O
,	O
computer	O
aided	O
design	O
,	O
etc	O
.	O
)	O
.	O
</s>
<s>
There	O
are	O
two	O
graphical	B-Algorithm
projection	I-Algorithm
categories	O
,	O
each	O
with	O
its	O
own	O
method	O
:	O
</s>
<s>
In	O
parallel	O
projection	B-Application
,	O
the	O
lines	O
of	O
sight	O
from	O
the	O
object	O
to	O
the	O
projection	B-Application
plane	O
are	O
parallel	O
to	O
each	O
other	O
.	O
</s>
<s>
Parallel	O
projection	B-Application
also	O
corresponds	O
to	O
a	O
perspective	B-Architecture
projection	I-Architecture
with	O
an	O
infinite	O
focal	B-Algorithm
length	I-Algorithm
(	O
the	O
distance	O
from	O
a	O
camera	O
's	O
lens	O
and	O
focal	O
point	O
)	O
,	O
or	O
"	O
zoom	O
"	O
.	O
</s>
<s>
Images	O
drawn	O
in	O
parallel	O
projection	B-Application
rely	O
upon	O
the	O
technique	O
of	O
axonometry	B-Application
(	O
"	O
to	O
measure	O
along	O
axes	O
"	O
)	O
,	O
as	O
described	O
in	O
Pohlke	O
's	O
theorem	O
.	O
</s>
<s>
In	O
general	O
,	O
the	O
resulting	O
image	O
is	O
oblique	O
(	O
the	O
rays	O
are	O
not	O
perpendicular	O
to	O
the	O
image	B-General_Concept
plane	I-General_Concept
)	O
;	O
but	O
in	O
special	O
cases	O
the	O
result	O
is	O
orthographic	O
(	O
the	O
rays	O
are	O
perpendicular	O
to	O
the	O
image	B-General_Concept
plane	I-General_Concept
)	O
.	O
</s>
<s>
Axonometry	B-Application
should	O
not	O
be	O
confused	O
with	O
axonometric	O
projection	B-Application
,	O
as	O
in	O
English	O
literature	O
the	O
latter	O
usually	O
refers	O
only	O
to	O
a	O
specific	O
class	O
of	O
pictorials	O
(	O
see	O
below	O
)	O
.	O
</s>
<s>
The	O
orthographic	O
projection	B-Application
is	O
derived	O
from	O
the	O
principles	O
of	O
descriptive	B-Language
geometry	I-Language
and	O
is	O
a	O
two-dimensional	O
representation	O
of	O
a	O
three-dimensional	O
object	O
.	O
</s>
<s>
It	O
is	O
a	O
parallel	O
projection	B-Application
(	O
the	O
lines	O
of	O
projection	B-Application
are	O
parallel	O
both	O
in	O
reality	O
and	O
in	O
the	O
projection	B-Application
plane	O
)	O
.	O
</s>
<s>
It	O
is	O
the	O
projection	B-Application
type	O
of	O
choice	O
for	O
working	B-Application
drawings	I-Application
.	O
</s>
<s>
To	O
project	B-General_Concept
the	O
3D	O
point	O
,	O
,	O
onto	O
the	O
2D	O
point	O
,	O
using	O
an	O
orthographic	O
projection	B-Application
parallel	O
to	O
the	O
y	O
axis	O
(	O
where	O
positive	O
y	O
represents	O
forward	O
direction	O
-	O
profile	O
view	O
)	O
,	O
the	O
following	O
equations	O
can	O
be	O
used	O
:	O
</s>
<s>
As	O
a	O
result	O
,	O
lengths	O
are	O
not	O
foreshortened	O
as	O
they	O
would	O
be	O
in	O
a	O
perspective	B-Architecture
projection	I-Architecture
.	O
</s>
<s>
With	O
multiview	O
projections	B-Application
,	O
up	O
to	O
six	O
pictures	O
(	O
called	O
primary	O
views	O
)	O
of	O
an	O
object	O
are	O
produced	O
,	O
with	O
each	O
projection	B-Application
plane	O
parallel	O
to	O
one	O
of	O
the	O
coordinate	O
axes	O
of	O
the	O
object	O
.	O
</s>
<s>
The	O
views	O
are	O
positioned	O
relative	O
to	O
each	O
other	O
according	O
to	O
either	O
of	O
two	O
schemes	O
:	O
first-angle	O
or	O
third-angle	O
projection	B-Application
.	O
</s>
<s>
In	O
oblique	O
projections	B-Application
the	O
parallel	O
projection	B-Application
rays	O
are	O
not	O
perpendicular	O
to	O
the	O
viewing	O
plane	O
as	O
with	O
orthographic	O
projection	B-Application
,	O
but	O
strike	O
the	O
projection	B-Application
plane	O
at	O
an	O
angle	O
other	O
than	O
ninety	O
degrees	O
.	O
</s>
<s>
In	O
both	O
orthographic	O
and	O
oblique	O
projection	B-Application
,	O
parallel	O
lines	O
in	O
space	O
appear	O
parallel	O
on	O
the	O
projected	O
image	O
.	O
</s>
<s>
Because	O
of	O
its	O
simplicity	O
,	O
oblique	O
projection	B-Application
is	O
used	O
exclusively	O
for	O
pictorial	O
purposes	O
rather	O
than	O
for	O
formal	O
,	O
working	B-Application
drawings	I-Application
.	O
</s>
<s>
The	O
distortion	O
created	O
thereby	O
is	O
usually	O
attenuated	O
by	O
aligning	O
one	O
plane	O
of	O
the	O
imaged	O
object	O
to	O
be	O
parallel	O
with	O
the	O
plane	O
of	O
projection	B-Application
thereby	O
creating	O
a	O
true	O
shape	O
,	O
full-size	O
image	O
of	O
the	O
chosen	O
plane	O
.	O
</s>
<s>
Special	O
types	O
of	O
oblique	O
projections	B-Application
are	O
:	O
</s>
<s>
In	O
cavalier	O
projection	B-Application
(	O
sometimes	O
cavalier	O
perspective	O
or	O
high	O
view	O
point	O
)	O
a	O
point	O
of	O
the	O
object	O
is	O
represented	O
by	O
three	O
coordinates	O
,	O
x	O
,	O
y	O
and	O
z	O
.	O
</s>
<s>
On	O
the	O
flat	O
drawing	O
,	O
two	O
axes	O
,	O
x	O
and	O
z	O
on	O
the	O
figure	O
,	O
are	O
perpendicular	O
and	O
the	O
length	O
on	O
these	O
axes	O
are	O
drawn	O
with	O
a	O
1:1	O
scale	O
;	O
it	O
is	O
thus	O
similar	O
to	O
the	O
dimetric	O
projections	B-Application
,	O
although	O
it	O
is	O
not	O
an	O
axonometric	O
projection	B-Application
,	O
as	O
the	O
third	O
axis	O
,	O
here	O
y	O
,	O
is	O
drawn	O
in	O
diagonal	O
,	O
making	O
an	O
arbitrary	O
angle	O
with	O
the	O
x″	O
axis	O
,	O
usually	O
30	O
or	O
45°	O
.	O
</s>
<s>
The	O
term	O
cabinet	O
projection	B-Application
(	O
sometimes	O
cabinet	O
perspective	O
)	O
stems	O
from	O
its	O
use	O
in	O
illustrations	O
by	O
the	O
furniture	O
industry	O
.	O
</s>
<s>
Unlike	O
cavalier	O
projection	B-Application
,	O
where	O
the	O
third	O
axis	O
keeps	O
its	O
length	O
,	O
with	O
cabinet	O
projection	B-Application
the	O
length	O
of	O
the	O
receding	O
lines	O
is	O
cut	O
in	O
half	O
.	O
</s>
<s>
A	O
variant	O
of	O
oblique	O
projection	B-Application
is	O
called	O
military	O
projection	B-Application
.	O
</s>
<s>
The	O
military	O
projection	B-Application
is	O
given	O
by	O
rotation	O
in	O
the	O
xy-plane	O
and	O
a	O
vertical	O
translation	O
an	O
amount	O
z	O
.	O
</s>
<s>
Axonometric	O
projections	B-Application
show	O
an	O
image	O
of	O
an	O
object	O
as	O
viewed	O
from	O
a	O
skew	O
direction	O
in	O
order	O
to	O
reveal	O
all	O
three	O
directions	O
(	O
axes	O
)	O
of	O
space	O
in	O
one	O
picture	O
.	O
</s>
<s>
Axonometric	O
projections	B-Application
may	O
be	O
either	O
orthographic	O
or	O
oblique	O
.	O
</s>
<s>
Axonometric	O
instrument	O
drawings	O
are	O
often	O
used	O
to	O
approximate	O
graphical	B-Architecture
perspective	I-Architecture
projections	B-Application
,	O
but	O
there	O
is	O
attendant	O
distortion	O
in	O
the	O
approximation	O
.	O
</s>
<s>
Because	O
pictorial	O
projections	B-Application
innately	O
contain	O
this	O
distortion	O
,	O
in	O
instrument	O
drawings	O
of	O
pictorials	O
great	O
liberties	O
may	O
then	O
be	O
taken	O
for	O
economy	O
of	O
effort	O
and	O
best	O
effect	O
.	O
</s>
<s>
Axonometric	O
projection	B-Application
is	O
further	O
subdivided	O
into	O
three	O
categories	O
:	O
isometric	O
projection	B-Application
,	O
dimetric	O
projection	B-Application
,	O
and	O
trimetric	O
projection	B-Application
,	O
depending	O
on	O
the	O
exact	O
angle	O
at	O
which	O
the	O
view	O
deviates	O
from	O
the	O
orthogonal	O
.	O
</s>
<s>
Axonometric	O
projections	B-Application
are	O
also	O
sometimes	O
known	O
as	O
auxiliary	O
views	O
,	O
as	O
opposed	O
to	O
the	O
primary	O
views	O
of	O
multiview	O
projections	B-Application
.	O
</s>
<s>
In	O
isometric	O
pictorials	O
(	O
for	O
methods	O
,	O
see	O
Isometric	O
projection	B-Application
)	O
,	O
the	O
direction	O
of	O
viewing	O
is	O
such	O
that	O
the	O
three	O
axes	O
of	O
space	O
appear	O
equally	O
foreshortened	O
,	O
and	O
there	O
is	O
a	O
common	O
angle	O
of	O
120°	O
between	O
them	O
.	O
</s>
<s>
In	O
dimetric	O
pictorials	O
(	O
for	O
methods	O
,	O
see	O
Dimetric	O
projection	B-Application
)	O
,	O
the	O
direction	O
of	O
viewing	O
is	O
such	O
that	O
two	O
of	O
the	O
three	O
axes	O
of	O
space	O
appear	O
equally	O
foreshortened	O
,	O
of	O
which	O
the	O
attendant	O
scale	O
and	O
angles	O
of	O
presentation	O
are	O
determined	O
according	O
to	O
the	O
angle	O
of	O
viewing	O
;	O
the	O
scale	O
of	O
the	O
third	O
direction	O
(	O
vertical	O
)	O
is	O
determined	O
separately	O
.	O
</s>
<s>
In	O
trimetric	O
pictorials	O
(	O
for	O
methods	O
,	O
see	O
Trimetric	O
projection	B-Application
)	O
,	O
the	O
direction	O
of	O
viewing	O
is	O
such	O
that	O
all	O
of	O
the	O
three	O
axes	O
of	O
space	O
appear	O
unequally	O
foreshortened	O
.	O
</s>
<s>
Objects	O
drawn	O
with	O
parallel	O
projection	B-Application
do	O
not	O
appear	O
larger	O
or	O
smaller	O
as	O
they	O
extend	O
closer	O
to	O
or	O
away	O
from	O
the	O
viewer	O
.	O
</s>
<s>
While	O
advantageous	O
for	O
architectural	B-Architecture
drawings	I-Architecture
,	O
where	O
measurements	O
must	O
be	O
taken	O
directly	O
from	O
the	O
image	O
,	O
the	O
result	O
is	O
a	O
perceived	O
distortion	O
,	O
since	O
unlike	O
perspective	B-Architecture
projection	I-Architecture
,	O
this	O
is	O
not	O
how	O
our	O
eyes	O
or	O
photography	O
normally	O
work	O
.	O
</s>
<s>
M	O
.	O
C	O
.	O
Escher	O
's	O
Waterfall	O
(	O
1961	O
)	O
,	O
while	O
not	O
strictly	O
utilizing	O
parallel	O
projection	B-Application
,	O
is	O
a	O
well-known	O
example	O
,	O
in	O
which	O
a	O
channel	O
of	O
water	O
seems	O
to	O
travel	O
unaided	O
along	O
a	O
downward	O
path	O
,	O
only	O
to	O
then	O
paradoxically	O
fall	O
once	O
again	O
as	O
it	O
returns	O
to	O
its	O
source	O
.	O
</s>
<s>
The	O
video	O
game	O
Fez	B-Application
uses	O
tricks	O
of	O
perspective	O
to	O
determine	O
where	O
a	O
player	O
can	O
and	O
cannot	O
move	O
in	O
a	O
puzzle-like	O
fashion	O
.	O
</s>
<s>
Perspective	B-Architecture
projection	I-Architecture
or	O
perspective	O
transformation	O
is	O
a	O
nonlinear	O
projection	B-Application
where	O
three	O
dimensional	O
objects	O
are	O
projected	O
on	O
a	O
picture	O
plane	O
.	O
</s>
<s>
For	O
example	O
,	O
if	O
railways	O
are	O
pictured	O
with	O
perspective	B-Architecture
projection	I-Architecture
,	O
they	O
appear	O
to	O
converge	O
towards	O
a	O
single	O
point	O
,	O
called	O
the	O
vanishing	B-General_Concept
point	I-General_Concept
.	O
</s>
<s>
Photographic	O
lenses	O
and	O
the	O
human	O
eye	O
work	O
in	O
the	O
same	O
way	O
,	O
therefore	O
perspective	B-Architecture
projection	I-Architecture
looks	O
most	O
realistic	O
.	O
</s>
<s>
Perspective	B-Architecture
projection	I-Architecture
is	O
usually	O
categorized	O
into	O
one-point	O
,	O
two-point	O
and	O
three-point	O
perspective	O
,	O
depending	O
on	O
the	O
orientation	O
of	O
the	O
projection	B-Application
plane	O
towards	O
the	O
axes	O
of	O
the	O
depicted	O
object	O
.	O
</s>
<s>
Graphical	B-Algorithm
projection	I-Algorithm
methods	O
rely	O
on	O
the	O
duality	O
between	O
lines	O
and	O
points	O
,	O
whereby	O
two	O
straight	O
lines	O
determine	O
a	O
point	O
while	O
two	O
points	O
determine	O
a	O
straight	O
line	O
.	O
</s>
<s>
The	O
orthogonal	O
projection	B-Application
of	O
the	O
eye	O
point	O
onto	O
the	O
picture	O
plane	O
is	O
called	O
the	O
principal	O
vanishing	B-General_Concept
point	I-General_Concept
(	O
P.P.	O
</s>
<s>
its	O
vanishing	B-General_Concept
point	I-General_Concept
,	O
found	O
at	O
the	O
intersection	O
between	O
the	O
parallel	O
line	O
from	O
the	O
eye	O
point	O
and	O
the	O
picture	O
plane	O
.	O
</s>
<s>
The	O
principal	O
vanishing	B-General_Concept
point	I-General_Concept
is	O
the	O
vanishing	B-General_Concept
point	I-General_Concept
of	O
all	O
horizontal	O
lines	O
perpendicular	O
to	O
the	O
picture	O
plane	O
.	O
</s>
<s>
The	O
vanishing	B-General_Concept
points	I-General_Concept
of	O
all	O
horizontal	O
lines	O
lie	O
on	O
the	O
horizon	O
line	O
.	O
</s>
<s>
If	O
,	O
as	O
is	O
often	O
the	O
case	O
,	O
the	O
picture	O
plane	O
is	O
vertical	O
,	O
all	O
vertical	O
lines	O
are	O
drawn	O
vertically	O
,	O
and	O
have	O
no	O
finite	O
vanishing	B-General_Concept
point	I-General_Concept
on	O
the	O
picture	O
plane	O
.	O
</s>
<s>
For	O
example	O
,	O
lines	O
traced	O
from	O
the	O
eye	O
point	O
at	O
45°	O
to	O
the	O
picture	O
plane	O
intersect	O
the	O
latter	O
along	O
a	O
circle	O
whose	O
radius	O
is	O
the	O
distance	O
of	O
the	O
eye	O
point	O
from	O
the	O
plane	O
,	O
thus	O
tracing	O
that	O
circle	O
aids	O
the	O
construction	O
of	O
all	O
the	O
vanishing	B-General_Concept
points	I-General_Concept
of	O
45°	O
lines	O
;	O
in	O
particular	O
,	O
the	O
intersection	O
of	O
that	O
circle	O
with	O
the	O
horizon	O
line	O
consists	O
of	O
two	O
distance	O
points	O
.	O
</s>
<s>
In	O
the	O
perspective	O
of	O
a	O
geometric	O
solid	O
on	O
the	O
right	O
,	O
after	O
choosing	O
the	O
principal	O
vanishing	B-General_Concept
point	I-General_Concept
—	O
which	O
determines	O
the	O
horizon	O
line	O
—	O
the	O
45°	O
vanishing	B-General_Concept
point	I-General_Concept
on	O
the	O
left	O
side	O
of	O
the	O
drawing	O
completes	O
the	O
characterization	O
of	O
the	O
(	O
equally	O
distant	O
)	O
point	O
of	O
view	O
.	O
</s>
<s>
Two	O
lines	O
are	O
drawn	O
from	O
the	O
orthogonal	O
projection	B-Application
of	O
each	O
vertex	O
,	O
one	O
at	O
45°	O
and	O
one	O
at	O
90°	O
to	O
the	O
picture	O
plane	O
.	O
</s>
<s>
Their	O
new	O
intersection	O
locates	O
the	O
projection	B-Application
of	O
the	O
map	O
.	O
</s>
<s>
While	O
orthographic	O
projection	B-Application
ignores	O
perspective	O
to	O
allow	O
accurate	O
measurements	O
,	O
perspective	B-Architecture
projection	I-Architecture
shows	O
distant	O
objects	O
as	O
smaller	O
to	O
provide	O
additional	O
realism	O
.	O
</s>
<s>
The	O
perspective	B-Architecture
projection	I-Architecture
requires	O
a	O
more	O
involved	O
definition	O
as	O
compared	O
to	O
orthographic	O
projections	B-Application
.	O
</s>
<s>
A	O
conceptual	O
aid	O
to	O
understanding	O
the	O
mechanics	O
of	O
this	O
projection	B-Application
is	O
to	O
imagine	O
the	O
2D	O
projection	B-Application
as	O
though	O
the	O
object(s )	O
are	O
being	O
viewed	O
through	O
a	O
camera	O
viewfinder	O
.	O
</s>
<s>
The	O
camera	O
's	O
position	O
,	O
orientation	O
,	O
and	O
field	O
of	O
view	O
control	O
the	O
behavior	O
of	O
the	O
projection	B-Application
transformation	O
.	O
</s>
<s>
–	O
the	O
display	B-General_Concept
surface	I-General_Concept
's	O
position	O
relative	O
to	O
the	O
camera	O
pinhole	O
C	O
.	O
</s>
<s>
This	O
transformed	O
point	O
can	O
then	O
be	O
projected	O
onto	O
the	O
2D	O
plane	O
using	O
the	O
formula	O
(	O
here	O
,	O
x/y	O
is	O
used	O
as	O
the	O
projection	B-Application
plane	O
;	O
literature	O
also	O
may	O
use	O
x/z	O
)	O
:	O
</s>
<s>
The	O
distance	O
of	O
the	O
viewer	O
from	O
the	O
display	B-General_Concept
surface	I-General_Concept
,	O
,	O
directly	O
relates	O
to	O
the	O
field	O
of	O
view	O
,	O
where	O
is	O
the	O
viewed	O
angle	O
.	O
</s>
<s>
In	O
which	O
is	O
the	O
display	O
size	O
,	O
is	O
the	O
recording	O
surface	O
size	O
(	O
CCD	B-Algorithm
or	O
Photographic	O
film	O
)	O
,	O
is	O
the	O
distance	O
from	O
the	O
recording	O
surface	O
to	O
the	O
entrance	O
pupil	O
(	O
camera	B-Algorithm
center	I-Algorithm
)	O
,	O
and	O
is	O
the	O
distance	O
,	O
from	O
the	O
3D	O
point	O
being	O
projected	O
,	O
to	O
the	O
entrance	O
pupil	O
.	O
</s>
<s>
A	O
"	O
weak	O
"	O
perspective	B-Architecture
projection	I-Architecture
uses	O
the	O
same	O
principles	O
of	O
an	O
orthographic	O
projection	B-Application
,	O
but	O
requires	O
the	O
scaling	O
factor	O
to	O
be	O
specified	O
,	O
thus	O
ensuring	O
that	O
closer	O
objects	O
appear	O
bigger	O
in	O
the	O
projection	B-Application
,	O
and	O
vice	O
versa	O
.	O
</s>
<s>
It	O
can	O
be	O
seen	O
as	O
a	O
hybrid	O
between	O
an	O
orthographic	O
and	O
a	O
perspective	B-Architecture
projection	I-Architecture
,	O
and	O
described	O
either	O
as	O
a	O
perspective	B-Architecture
projection	I-Architecture
with	O
individual	O
point	O
depths	O
replaced	O
by	O
an	O
average	O
constant	O
depth	O
,	O
or	O
simply	O
as	O
an	O
orthographic	O
projection	B-Application
plus	O
a	O
scaling	O
.	O
</s>
<s>
The	O
weak-perspective	O
model	O
thus	O
approximates	O
perspective	B-Architecture
projection	I-Architecture
while	O
using	O
a	O
simpler	O
model	O
,	O
similar	O
to	O
the	O
pure	O
(	O
unscaled	O
)	O
orthographic	O
perspective	O
.	O
</s>
<s>
With	O
these	O
conditions	O
,	O
it	O
can	O
be	O
assumed	O
that	O
all	O
points	O
on	O
a	O
3D	O
object	O
are	O
at	O
the	O
same	O
distance	O
from	O
the	O
camera	O
without	O
significant	O
errors	O
in	O
the	O
projection	B-Application
(	O
compared	O
to	O
the	O
full	O
perspective	O
model	O
)	O
.	O
</s>
<s>
assuming	O
focal	B-Algorithm
length	I-Algorithm
.	O
</s>
<s>
You	O
can	O
use	O
that	O
to	O
do	O
clipping	O
techniques	O
,	O
replacing	O
the	O
variables	O
with	O
values	O
of	O
the	O
point	O
that	O
's	O
are	O
out	O
of	O
the	O
FOV-angle	O
and	O
the	O
point	O
inside	O
Camera	B-General_Concept
Matrix	I-General_Concept
.	O
</s>
<s>
This	O
technique	O
,	O
also	O
known	O
as	O
"	O
Inverse	O
Camera	O
"	O
,	O
is	O
a	O
Perspective	B-Architecture
Projection	I-Architecture
Calculus	O
with	O
known	O
values	O
to	O
calculate	O
the	O
last	O
point	O
on	O
visible	O
angle	O
,	O
projecting	O
from	O
the	O
invisible	O
point	O
,	O
after	O
all	O
needed	O
transformations	O
finished	O
.	O
</s>
