Part vs Assembly¶
Part is an atomic component; it cannot be disassembled, and it
is typically made of a single material.
Assembly would typically hold itself together, as an intermedite
step of construction.
Part is not to be confused with a primative (like a cube, sphere,
or cylinder to name a few), nor is it to be confused with constructive
For a detailed example of a hierarchy, have a look at Make your own Assembly.
If you were to make something from scratch, from raw materials, each
Part is each individual object after material processing
(such as forging, printing, or milling, just to name a few).
Or put another way…
If you had a thing with you, and you pulled it apart as much as possible (this may involve unscrewing, prying apart, de-soldering, just to name a few).
Each time you pull out a smaller thing:
- if it can be disassembled further, that is an
- if it cannot be pulled apart, then it’s a
When you have recursively disassembled everything, you will only be left
Exceptions to the rule¶
Just like any other rule, there are exceptions:
For example, an SD Card has many components inside it, but since it can be
assumed that it won’t be pulled apart, or need to be constructed, an SD Card
will most likely be represented by a single
Conversely, a sticker (like a branding sticker) cannot be disassembled.
But visually you may want its orientation to be recognisable, or
you just want it to render properly. This is where a
Part is limited,
because it can only be one color. So the sticker may be 2
instances in an
Assembly, one for the backing, and one for the text,
A well designed
Assembly is something that can be used in others’
Consider how others may want to use your
Assembly, and empower the
class with the tools necessary to make their job easy.
More discussion on this in Make your own Assembly.