<s>
Assembly	O
modeling	O
is	O
a	O
technology	O
and	O
method	O
used	O
by	O
computer-aided	B-Application
design	I-Application
and	O
product	O
visualization	O
computer	O
software	O
systems	O
to	O
handle	O
multiple	O
files	O
that	O
represent	O
components	O
within	O
a	O
product	O
.	O
</s>
<s>
All	O
CAD	B-Application
and	O
CPD	O
systems	O
support	O
this	O
form	O
of	O
bottom-up	O
construction	O
.	O
</s>
<s>
Components	O
can	O
be	O
positioned	O
within	O
the	O
product	O
assembly	O
using	O
absolute	O
coordinate	O
placement	O
methods	O
or	O
by	O
means	O
of	O
mating	B-Algorithm
conditions	I-Algorithm
.	O
</s>
<s>
Mating	B-Algorithm
conditions	I-Algorithm
are	O
definitions	O
of	O
the	O
relative	O
position	O
of	O
components	O
between	O
each	O
other	O
;	O
for	O
example	O
alignment	O
of	O
axis	O
of	O
two	O
holes	O
or	O
distance	O
of	O
two	O
faces	O
from	O
one	O
another	O
.	O
</s>
<s>
The	O
final	O
position	O
of	O
all	O
components	O
based	O
on	O
these	O
relationships	O
is	O
calculated	O
using	O
a	O
geometry	B-Application
constraint	I-Application
engine	I-Application
built	O
into	O
the	O
CAD	B-Application
or	O
visualization	O
package	O
.	O
</s>
