<s>
An	O
engineering	B-Architecture
drawing	I-Architecture
is	O
a	O
type	O
of	O
technical	B-Application
drawing	I-Application
that	O
is	O
used	O
to	O
convey	O
information	O
about	O
an	O
object	O
.	O
</s>
<s>
Usually	O
,	O
a	O
number	O
of	O
drawings	B-Application
are	O
necessary	O
to	O
completely	O
specify	O
even	O
a	O
simple	O
component	O
.	O
</s>
<s>
The	O
drawings	B-Application
are	O
linked	O
together	O
by	O
a	O
master	O
drawing	O
or	O
assembly	O
drawing	O
which	O
gives	O
the	O
drawing	O
numbers	O
of	O
the	O
subsequent	O
detailed	O
components	O
,	O
quantities	O
required	O
,	O
construction	O
materials	O
and	O
possibly	O
3D	O
images	O
that	O
can	O
be	O
used	O
to	O
locate	O
individual	O
items	O
.	O
</s>
<s>
The	O
process	O
of	O
producing	O
engineering	B-Architecture
drawings	I-Architecture
is	O
often	O
referred	O
to	O
as	O
technical	B-Application
drawing	I-Application
or	O
drafting	O
(	O
draughting	O
)	O
.	O
</s>
<s>
Drawings	B-Application
typically	O
contain	O
multiple	O
views	O
of	O
a	O
component	O
,	O
although	O
additional	O
scratch	O
views	O
may	O
be	O
added	O
of	O
details	O
for	O
further	O
explanation	O
.	O
</s>
<s>
More	O
detailed	O
production	O
drawings	B-Application
may	O
be	O
produced	O
based	O
on	O
the	O
information	O
given	O
in	O
an	O
engineering	B-Architecture
drawing	I-Architecture
.	O
</s>
<s>
Drawings	B-Application
have	O
an	O
information	O
box	O
or	O
title	O
block	O
containing	O
who	O
drew	O
the	O
drawing	O
,	O
who	O
approved	O
it	O
,	O
units	O
of	O
dimensions	O
,	O
meaning	O
of	O
views	O
,	O
the	O
title	O
of	O
the	O
drawing	O
and	O
the	O
drawing	O
number	O
.	O
</s>
<s>
Technical	B-Application
drawing	I-Application
has	O
existed	O
since	O
ancient	O
times	O
.	O
</s>
<s>
Complex	O
technical	B-Application
drawings	I-Application
were	O
made	O
in	O
renaissance	O
times	O
,	O
such	O
as	O
the	O
drawings	B-Application
of	O
Leonardo	O
da	O
Vinci	O
.	O
</s>
<s>
Modern	O
engineering	B-Architecture
drawing	I-Architecture
,	O
with	O
its	O
precise	O
conventions	O
of	O
orthographic	O
projection	O
and	O
scale	O
,	O
arose	O
in	O
France	O
at	O
a	O
time	O
when	O
the	O
Industrial	O
Revolution	O
was	O
in	O
its	O
infancy	O
.	O
</s>
<s>
L	O
.	O
T	O
.	O
C	O
.	O
Rolt	O
's	O
biography	O
of	O
Isambard	O
Kingdom	O
Brunel	O
says	O
of	O
his	O
father	O
,	O
Marc	O
Isambard	O
Brunel	O
,	O
that	O
"	O
It	O
seems	O
fairly	O
certain	O
that	O
Marc	O
's	O
drawings	B-Application
of	O
his	O
block-making	O
machinery	O
(	O
in	O
1799	O
)	O
made	O
a	O
contribution	O
to	O
British	O
engineering	O
technique	O
much	O
greater	O
than	O
the	O
machines	O
they	O
represented	O
.	O
</s>
<s>
Engineering	B-Architecture
drawings	I-Architecture
specify	O
requirements	O
of	O
a	O
component	O
or	O
assembly	O
which	O
can	O
be	O
complicated	O
.	O
</s>
<s>
Standardization	O
also	O
aids	O
internationalization	O
,	O
because	O
people	O
from	O
different	O
countries	O
who	O
speak	O
different	O
languages	O
can	O
read	O
the	O
same	O
engineering	B-Architecture
drawing	I-Architecture
,	O
and	O
interpret	O
it	O
the	O
same	O
way	O
.	O
</s>
<s>
One	O
major	O
set	O
of	O
engineering	B-Architecture
drawing	I-Architecture
standards	O
is	O
ASME	O
Y14.5	O
and	O
Y14.5M	O
(	O
most	O
recently	O
revised	O
in	O
2009	O
)	O
.	O
</s>
<s>
Britain	O
,	O
BS	B-Application
8888	I-Application
(	O
Technical	O
Product	O
Specification	O
)	O
has	O
undergone	O
important	O
updates	O
in	O
the	O
2010s	O
.	O
</s>
<s>
For	O
centuries	O
,	O
until	O
the	O
1970s	O
,	O
all	O
engineering	B-Architecture
drawing	I-Architecture
was	O
done	O
manually	O
by	O
using	O
pencil	O
and	O
pen	O
on	O
paper	O
or	O
other	O
substrate	O
(	O
e.g.	O
,	O
vellum	O
,	O
mylar	O
)	O
.	O
</s>
<s>
Since	O
the	O
advent	O
of	O
computer-aided	B-Application
design	I-Application
(	O
CAD	B-Application
)	O
,	O
engineering	B-Architecture
drawing	I-Architecture
has	O
been	O
done	O
more	O
and	O
more	O
in	O
the	O
electronic	O
medium	O
with	O
each	O
passing	O
decade	O
.	O
</s>
<s>
Today	O
most	O
engineering	B-Architecture
drawing	I-Architecture
is	O
done	O
with	O
CAD	B-Application
,	O
but	O
pencil	O
and	O
paper	O
have	O
not	O
entirely	O
disappeared	O
.	O
</s>
<s>
Some	O
of	O
the	O
tools	B-Application
of	I-Application
manual	I-Application
drafting	I-Application
include	O
pencils	O
,	O
pens	O
and	O
their	O
ink	O
,	O
straightedges	O
,	O
T-squares	B-Application
,	O
French	O
curves	O
,	O
triangles	O
,	O
rulers	O
,	O
protractors	O
,	O
dividers	O
,	O
compasses	O
,	O
scales	O
,	O
erasers	O
,	O
and	O
tacks	O
or	O
push	O
pins	O
.	O
</s>
<s>
(	O
Slide	O
rules	O
used	O
to	O
number	O
among	O
the	O
supplies	O
,	O
too	O
,	O
but	O
nowadays	O
even	O
manual	O
drafting	O
,	O
when	O
it	O
occurs	O
,	O
benefits	O
from	O
a	O
pocket	O
calculator	B-Application
or	O
its	O
onscreen	O
equivalent	O
.	O
)	O
</s>
<s>
The	O
English	O
idiom	O
"	O
to	O
go	O
back	O
to	O
the	O
drawing	O
board	O
"	O
,	O
which	O
is	O
a	O
figurative	O
phrase	O
meaning	O
to	O
rethink	O
something	O
altogether	O
,	O
was	O
inspired	O
by	O
the	O
literal	O
act	O
of	O
discovering	O
design	O
errors	O
during	O
production	O
and	O
returning	O
to	O
a	O
drawing	O
board	O
to	O
revise	O
the	O
engineering	B-Architecture
drawing	I-Architecture
.	O
</s>
<s>
Drafting	B-Application
machines	I-Application
are	O
devices	O
that	O
aid	O
manual	O
drafting	O
by	O
combining	O
drawing	O
boards	O
,	O
straightedges	O
,	O
pantographs	O
,	O
and	O
other	O
tools	O
into	O
one	O
integrated	O
drawing	O
environment	O
.	O
</s>
<s>
CAD	B-Application
provides	O
their	O
virtual	O
equivalents	O
.	O
</s>
<s>
Producing	O
drawings	B-Application
usually	O
involves	O
creating	O
an	O
original	O
that	O
is	O
then	O
reproduced	O
,	O
generating	O
multiple	O
copies	O
to	O
be	O
distributed	O
to	O
the	O
shop	O
floor	O
,	O
vendors	O
,	O
company	O
archives	O
,	O
and	O
so	O
on	O
.	O
</s>
<s>
The	O
classic	O
reproduction	O
methods	O
involved	O
blue	O
and	O
white	O
appearances	O
(	O
whether	O
white-on-blue	B-Application
or	O
blue-on-white	B-Application
)	O
,	O
which	O
is	O
why	O
engineering	B-Architecture
drawings	I-Architecture
were	O
long	O
called	O
,	O
and	O
even	O
today	O
are	O
still	O
often	O
called	O
,	O
"	O
blueprints	B-Application
"	O
or	O
"	O
bluelines	B-Application
"	O
,	O
even	O
though	O
those	O
terms	O
are	O
anachronistic	O
from	O
a	O
literal	O
perspective	B-Architecture
,	O
since	O
most	O
copies	O
of	O
engineering	B-Architecture
drawings	I-Architecture
today	O
are	O
made	O
by	O
more	O
modern	O
methods	O
(	O
often	O
inkjet	O
or	O
laser	O
printing	O
)	O
that	O
yield	O
black	O
or	O
multicolour	O
lines	O
on	O
white	O
paper	O
.	O
</s>
<s>
The	O
more	O
generic	O
term	O
"	O
print	O
"	O
is	O
now	O
in	O
common	O
usage	O
in	O
the	O
U.S.	O
to	O
mean	O
any	O
paper	O
copy	O
of	O
an	O
engineering	B-Architecture
drawing	I-Architecture
.	O
</s>
<s>
In	O
the	O
case	O
of	O
CAD	B-Application
drawings	B-Application
,	O
the	O
original	O
is	O
the	O
CAD	B-Application
file	I-Application
,	O
and	O
the	O
printouts	B-General_Concept
of	O
that	O
file	O
are	O
the	O
"	O
prints	O
"	O
.	O
</s>
<s>
Almost	O
all	O
engineering	B-Architecture
drawings	I-Architecture
(	O
except	O
perhaps	O
reference-only	O
views	O
or	O
initial	O
sketches	O
)	O
communicate	O
not	O
only	O
geometry	O
(	O
shape	O
and	O
location	O
)	O
but	O
also	O
dimensions	O
and	O
tolerances	O
for	O
those	O
characteristics	O
.	O
</s>
<s>
Coordinate	O
dimensioning	O
was	O
the	O
sole	O
best	O
option	O
until	O
the	O
post-World	O
War	O
II	O
era	O
saw	O
the	O
development	O
of	O
geometric	B-Application
dimensioning	I-Application
and	I-Application
tolerancing	I-Application
(	O
GD&T	B-Application
)	O
,	O
which	O
departs	O
from	O
the	O
limitations	O
of	O
coordinate	O
dimensioning	O
(	O
e.g.	O
,	O
rectangular-only	O
tolerance	O
zones	O
,	O
tolerance	O
stacking	O
)	O
to	O
allow	O
the	O
most	O
logical	O
tolerancing	O
of	O
both	O
geometry	O
and	O
dimensions	O
(	O
that	O
is	O
,	O
both	O
form	O
 [ shapes/locations ] 	O
and	O
sizes	O
)	O
.	O
</s>
<s>
Drawings	B-Application
convey	O
the	O
following	O
critical	O
information	O
:	O
</s>
<s>
cutting	O
plane	O
–	O
are	O
thin	O
,	O
medium-dashed	O
lines	O
,	O
or	O
thick	O
alternately	O
long	O
-	O
and	O
double	O
short-dashed	O
that	O
may	O
be	O
used	O
to	O
define	O
sections	O
for	O
section	B-Application
views	I-Application
.	O
</s>
<s>
section	O
–	O
are	O
thin	O
lines	O
in	O
a	O
pattern	O
(	O
pattern	O
determined	O
by	O
the	O
material	O
being	O
"	O
cut	O
"	O
or	O
"	O
sectioned	O
"	O
)	O
used	O
to	O
indicate	O
surfaces	O
in	O
section	B-Application
views	I-Application
resulting	O
from	O
"	O
cutting	O
"	O
.	O
</s>
<s>
Type	O
F	O
lines	O
are	O
Type	O
E	O
lines	O
,	O
except	O
these	O
are	O
used	O
for	O
drawings	B-Application
in	O
electrotechnology	O
.	O
</s>
<s>
First-angle	O
projection	O
is	O
the	O
ISO	B-Application
standard	I-Application
and	O
is	O
primarily	O
used	O
in	O
Europe	O
.	O
</s>
<s>
The	O
true	O
size	O
and	O
shape	O
of	O
any	O
feature	O
in	O
an	O
engineering	B-Architecture
drawing	I-Architecture
can	O
only	O
be	O
known	O
when	O
the	O
Line	O
of	O
Sight	O
(	O
LOS	O
)	O
is	O
perpendicular	O
to	O
the	O
plane	O
being	O
referenced	O
.	O
</s>
<s>
One	O
of	O
the	O
things	O
that	O
makes	O
isometric	O
drawings	B-Application
so	O
attractive	O
is	O
the	O
ease	O
with	O
which	O
60°	O
angles	O
can	O
be	O
constructed	O
with	O
only	O
a	O
compass	O
and	O
straightedge	O
.	O
</s>
<s>
Perspective	B-Architecture
is	O
an	O
approximate	O
representation	O
on	O
a	O
flat	O
surface	O
,	O
of	O
an	O
image	O
as	O
it	O
is	O
perceived	O
by	O
the	O
eye	O
.	O
</s>
<s>
The	O
two	O
most	O
characteristic	O
features	O
of	O
perspective	B-Architecture
are	O
that	O
objects	O
are	O
drawn	O
:	O
</s>
<s>
Projected	O
views	O
(	O
either	O
Auxiliary	O
or	O
Multiview	O
)	O
which	O
show	O
a	O
cross	B-Application
section	I-Application
of	O
the	O
source	O
object	O
along	O
the	O
specified	O
cut	O
plane	O
.	O
</s>
<s>
In	O
assembly	O
drawings	B-Application
,	O
hardware	O
components	O
(	O
e.g.	O
</s>
<s>
Plans	O
are	O
usually	O
"	O
scale	O
drawings	B-Application
"	O
,	O
meaning	O
that	O
the	O
plans	O
are	O
drawn	O
at	O
specific	O
ratio	O
relative	O
to	O
the	O
actual	O
size	O
of	O
the	O
place	O
or	O
object	O
.	O
</s>
<s>
Various	O
scales	O
may	O
be	O
used	O
for	O
different	O
drawings	B-Application
in	O
a	O
set	O
.	O
</s>
<s>
Scale	O
is	O
a	O
nuanced	O
subject	O
in	O
the	O
use	O
of	O
engineering	B-Architecture
drawings	I-Architecture
.	O
</s>
<s>
On	O
one	O
hand	O
,	O
it	O
is	O
a	O
general	O
principle	O
of	O
engineering	B-Architecture
drawings	I-Architecture
that	O
they	O
are	O
projected	O
using	O
standardized	O
,	O
mathematically	O
certain	O
projection	O
methods	O
and	O
rules	O
.	O
</s>
<s>
Thus	O
,	O
great	O
effort	O
is	O
put	O
into	O
having	O
an	O
engineering	B-Architecture
drawing	I-Architecture
accurately	O
depict	O
size	O
,	O
shape	O
,	O
form	O
,	O
aspect	B-Device
ratios	I-Device
between	O
features	O
,	O
and	O
so	O
on	O
.	O
</s>
<s>
And	O
yet	O
,	O
on	O
the	O
other	O
hand	O
,	O
there	O
is	O
another	O
general	O
principle	O
of	O
engineering	B-Architecture
drawing	I-Architecture
that	O
nearly	O
diametrically	O
opposes	O
all	O
this	O
effort	O
and	O
intent	O
—	O
that	O
is	O
,	O
the	O
principle	O
that	O
users	O
are	O
not	O
to	O
scale	O
the	O
drawing	O
to	O
infer	O
a	O
dimension	O
not	O
labeled	O
.	O
</s>
<s>
This	O
stern	O
admonition	O
is	O
often	O
repeated	O
on	O
drawings	B-Application
,	O
via	O
a	O
boilerplate	O
note	O
in	O
the	O
title	O
block	O
telling	O
the	O
user	O
,	O
"	O
DO	O
NOT	O
SCALE	O
DRAWING.	O
"	O
</s>
<s>
The	O
first	O
principle	O
—	O
that	O
drawings	B-Application
will	O
be	O
made	O
so	O
carefully	O
and	O
accurately	O
—	O
serves	O
the	O
prime	O
goal	O
of	O
why	O
engineering	B-Architecture
drawing	I-Architecture
even	O
exists	O
,	O
which	O
is	O
successfully	O
communicating	O
part	O
definition	O
and	O
acceptance	O
criteria	O
—	O
including	O
"	O
what	O
the	O
part	O
should	O
look	O
like	O
if	O
you	O
've	O
made	O
it	O
correctly.	O
"	O
</s>
<s>
But	O
in	O
some	O
ways	O
,	O
the	O
advent	O
of	O
the	O
CAD	B-Application
and	O
MBD	O
era	O
challenges	O
these	O
assumptions	O
that	O
were	O
formed	O
many	O
decades	O
ago	O
.	O
</s>
<s>
Even	O
in	O
dealing	O
with	O
2D	O
drawings	B-Application
,	O
the	O
manufacturing	O
world	O
has	O
changed	O
since	O
the	O
days	O
when	O
people	O
paid	O
attention	O
to	O
the	O
scale	O
ratio	O
claimed	O
on	O
the	O
print	O
,	O
or	O
counted	O
on	O
its	O
accuracy	O
.	O
</s>
<s>
Today	O
,	O
in	O
the	O
era	O
of	O
ubiquitous	O
desktop	O
printing	O
,	O
where	O
original	O
drawings	B-Application
or	O
scaled	O
prints	O
are	O
often	O
scanned	O
on	O
a	O
scanner	O
and	O
saved	O
as	O
a	O
PDF	O
file	O
,	O
which	O
is	O
then	O
printed	O
at	O
any	O
percent	O
magnification	O
that	O
the	O
user	O
deems	O
handy	O
(	O
such	O
as	O
"	O
fit	O
to	O
paper	O
size	O
"	O
)	O
,	O
users	O
have	O
pretty	O
much	O
given	O
up	O
caring	O
what	O
scale	O
ratio	O
is	O
claimed	O
in	O
the	O
"	O
scale	O
"	O
box	O
of	O
the	O
title	O
block	O
.	O
</s>
<s>
Sizes	O
of	O
drawings	B-Application
typically	O
comply	O
with	O
either	O
of	O
two	O
different	O
standards	O
,	O
ISO	O
(	O
World	O
Standard	O
)	O
or	O
ANSI/ASME	O
Y14.1	O
(	O
American	O
)	O
.	O
</s>
<s>
Engineering	B-Architecture
drawings	I-Architecture
could	O
be	O
readily	O
doubled	O
(	O
or	O
halved	O
)	O
in	O
size	O
and	O
put	O
on	O
the	O
next	O
larger	O
(	O
or	O
,	O
respectively	O
,	O
smaller	O
)	O
size	O
of	O
paper	O
with	O
no	O
waste	O
of	O
space	O
.	O
</s>
<s>
All	O
ISO	O
paper	O
sizes	O
have	O
the	O
same	O
aspect	B-Device
ratio	I-Device
,	O
one	O
to	O
the	O
square	O
root	O
of	O
2	O
,	O
meaning	O
that	O
a	O
document	O
designed	O
for	O
any	O
given	O
size	O
can	O
be	O
enlarged	O
or	O
reduced	O
to	O
any	O
other	O
size	O
and	O
will	O
fit	O
perfectly	O
.	O
</s>
<s>
Technical	O
lettering	O
is	O
the	O
process	O
of	O
forming	O
letters	O
,	O
numerals	O
,	O
and	O
other	O
characters	O
in	O
technical	B-Application
drawing	I-Application
.	O
</s>
<s>
Engineering	B-Architecture
drawings	I-Architecture
use	O
a	O
Gothic	O
sans-serif	O
script	O
,	O
formed	O
by	O
a	O
series	O
of	O
short	O
strokes	O
.	O
</s>
<s>
Lower	O
case	O
letters	O
are	O
rare	O
in	O
most	O
drawings	B-Application
of	O
machines	O
.	O
</s>
<s>
When	O
CAD	B-Application
drawings	B-Application
became	O
more	O
popular	O
,	O
especially	O
using	O
US	O
American	O
software	O
,	O
such	O
as	O
AutoCAD	O
,	O
the	O
nearest	O
font	O
to	O
this	O
ISO	B-Application
standard	I-Application
font	O
was	O
Romantic	O
Simplex	O
(	O
RomanS	O
)	O
-	O
a	O
proprietary	O
shx	O
font	O
)	O
with	O
a	O
manually	O
adjusted	O
width	O
factor	O
(	O
over	O
ride	O
)	O
to	O
make	O
it	O
look	O
as	O
near	O
to	O
the	O
ISO	O
lettering	O
for	O
the	O
drawing	O
board	O
.	O
</s>
<s>
In	O
more	O
recent	O
revisions	O
of	O
software	O
packages	O
,	O
the	O
TrueType	O
font	O
ISOCPEUR	O
reliably	O
reproduces	O
the	O
original	O
drawing	O
board	O
lettering	O
stencil	O
style	O
,	O
however	O
,	O
many	O
drawings	B-Application
have	O
switched	O
to	O
the	O
ubiquitous	O
Arial.ttf	O
.	O
</s>
<s>
Every	O
engineering	B-Architecture
drawing	I-Architecture
must	O
have	O
a	O
title	O
block	O
.	O
</s>
<s>
The	O
title	O
block	O
(	O
T/B	O
,	O
TB	O
)	O
is	O
an	O
area	O
of	O
the	O
drawing	O
that	O
conveys	O
header-type	O
information	O
about	O
the	O
drawing	O
,	O
such	O
as	O
:	O
</s>
<s>
ISO	B-Application
7200	I-Application
specifies	O
the	O
data	O
fields	O
used	O
in	O
title	O
blocks	O
.	O
</s>
<s>
The	O
revisions	O
block	O
(	O
rev	O
block	O
)	O
is	O
a	O
tabulated	O
list	O
of	O
the	O
revisions	O
(	O
versions	O
)	O
of	O
the	O
drawing	O
,	O
documenting	O
the	O
revision	B-Architecture
control	I-Architecture
.	O
</s>
<s>
"	O
FL5	O
"	O
(	O
flagnote	O
5	O
)	O
and	O
"	O
D5	O
"	O
(	O
delta	O
note	O
5	O
)	O
are	O
typical	O
ways	O
to	O
abbreviate	O
in	O
ASCII-only	O
contexts	O
.	O
</s>
<s>
Some	O
drawings	B-Application
call	O
out	O
dimensions	O
with	O
parameter	O
names	O
(	O
that	O
is	O
,	O
variables	O
,	O
such	O
a	O
"	O
A	O
"	O
,	O
"	O
B	O
"	O
,	O
"	O
C	O
"	O
)	O
,	O
then	O
tabulate	O
rows	O
of	O
parameter	O
values	O
for	O
each	O
part	O
number	O
.	O
</s>
<s>
As	O
in	O
many	O
technical	O
fields	O
,	O
a	O
wide	O
array	O
of	O
abbreviations	O
and	O
symbols	O
have	O
been	O
developed	O
in	O
engineering	B-Architecture
drawing	I-Architecture
during	O
the	O
20th	O
and	O
21st	O
centuries	O
.	O
</s>
<s>
Most	O
engineering	B-Architecture
drawings	I-Architecture
are	O
language-independent	O
—	O
words	O
are	O
confined	O
to	O
the	O
title	O
block	O
;	O
symbols	O
are	O
used	O
in	O
place	O
of	O
words	O
elsewhere	O
.	O
</s>
<s>
With	O
the	O
advent	O
of	O
computer	O
generated	O
drawings	B-Application
for	O
manufacturing	O
and	O
machining	O
,	O
many	O
symbols	O
have	O
fallen	O
out	O
of	O
common	O
use	O
.	O
</s>
<s>
For	O
example	O
,	O
ASME	O
Y14.5M	O
1994	O
excludes	O
a	O
few	O
elements	O
that	O
convey	O
critical	O
information	O
as	O
contained	O
in	O
older	O
US	O
Navy	O
drawings	B-Application
and	O
aircraft	O
manufacturing	O
drawings	B-Application
of	O
World	O
War	O
2	O
vintage	O
.	O
</s>
<s>
Here	O
is	O
an	O
example	O
of	O
an	O
engineering	B-Architecture
drawing	I-Architecture
(	O
an	O
isometric	O
view	O
of	O
the	O
same	O
object	O
is	O
shown	O
above	O
)	O
.	O
</s>
<s>
An	O
engineering	B-Architecture
drawing	I-Architecture
is	O
a	O
legal	O
document	O
(	O
that	O
is	O
,	O
a	O
legal	O
instrument	O
)	O
,	O
because	O
it	O
communicates	O
all	O
the	O
needed	O
information	O
about	O
"	O
what	O
is	O
wanted	O
"	O
to	O
the	O
people	O
who	O
will	O
expend	O
resources	O
turning	O
the	O
idea	O
into	O
a	O
reality	O
.	O
</s>
<s>
For	O
centuries	O
,	O
engineering	B-Architecture
drawing	I-Architecture
was	O
the	O
sole	O
method	O
of	O
transferring	O
information	O
from	O
design	O
into	O
manufacture	O
.	O
</s>
<s>
In	O
MBD	O
,	O
the	O
information	O
captured	O
by	O
the	O
CAD	B-Application
software	I-Application
app	O
is	O
fed	O
automatically	O
into	O
a	O
CAM	O
app	O
(	O
computer-aided	O
manufacturing	O
)	O
,	O
which	O
(	O
with	O
or	O
without	O
postprocessing	O
apps	O
)	O
creates	O
code	O
in	O
other	O
languages	O
such	O
as	O
G-code	O
to	O
be	O
executed	O
by	O
a	O
CNC	O
machine	O
tool	O
(	O
computer	O
numerical	O
control	O
)	O
,	O
3D	O
printer	O
,	O
or	O
(	O
increasingly	O
)	O
a	O
hybrid	O
machine	O
tool	O
that	O
uses	O
both	O
.	O
</s>
<s>
Thus	O
today	O
it	O
is	O
often	O
the	O
case	O
that	O
the	O
information	O
travels	O
from	O
the	O
mind	O
of	O
the	O
designer	O
into	O
the	O
manufactured	O
component	O
without	O
having	O
ever	O
been	O
codified	O
by	O
an	O
engineering	B-Architecture
drawing	I-Architecture
.	O
</s>
<s>
In	O
MBD	O
,	O
the	O
dataset	B-General_Concept
,	O
not	O
a	O
drawing	O
,	O
is	O
the	O
legal	O
instrument	O
.	O
</s>
<s>
The	O
term	O
"	O
technical	O
data	O
package	O
"	O
(	O
TDP	O
)	O
is	O
now	O
used	O
to	O
refer	O
to	O
the	O
complete	O
package	O
of	O
information	O
(	O
in	O
one	O
medium	O
or	O
another	O
)	O
that	O
communicates	O
information	O
from	O
design	O
to	O
production	O
(	O
such	O
as	O
3D-model	O
datasets	B-General_Concept
,	O
engineering	B-Architecture
drawings	I-Architecture
,	O
engineering	O
change	O
orders	O
(	O
ECOs	O
)	O
,	O
spec	O
revisions	O
and	O
addenda	O
,	O
and	O
so	O
on	O
)	O
.	O
</s>
<s>
It	O
still	O
takes	O
CAD/CAM	O
programmers	O
,	O
CNC	O
setup	O
workers	O
,	O
and	O
CNC	O
operators	O
to	O
do	O
manufacturing	O
,	O
as	O
well	O
as	O
other	O
people	O
such	O
as	O
quality	O
assurance	O
staff	O
(	O
inspectors	O
)	O
and	O
logistics	O
staff	O
(	O
for	O
materials	O
handling	O
,	O
shipping-and-receiving	O
,	O
and	O
front	O
office	O
functions	O
)	O
.	O
</s>
<s>
These	O
workers	O
often	O
use	O
drawings	B-Application
in	O
the	O
course	O
of	O
their	O
work	O
that	O
have	O
been	O
produced	O
from	O
the	O
MBD	O
dataset	B-General_Concept
.	O
</s>
<s>
When	O
proper	O
procedures	O
are	O
being	O
followed	O
,	O
a	O
clear	O
chain	O
of	O
precedence	O
is	O
always	O
documented	O
,	O
such	O
that	O
when	O
a	O
person	O
looks	O
at	O
a	O
drawing	O
,	O
s/he	O
is	O
told	O
by	O
a	O
note	O
thereon	O
that	O
this	O
drawing	O
is	O
not	O
the	O
governing	O
instrument	O
(	O
because	O
the	O
MBD	O
dataset	B-General_Concept
is	O
)	O
.	O
</s>
<s>
In	O
these	O
cases	O
,	O
the	O
drawing	O
is	O
still	O
a	O
useful	O
document	O
,	O
although	O
legally	O
it	O
is	O
classified	O
as	O
"	O
for	O
reference	O
only	O
"	O
,	O
meaning	O
that	O
if	O
any	O
controversies	O
or	O
discrepancies	O
arise	O
,	O
it	O
is	O
the	O
MBD	O
dataset	B-General_Concept
,	O
not	O
the	O
drawing	O
,	O
that	O
governs	O
.	O
</s>
