A part a design built: its id, name and the body it is, its shape and per face the names
references find it by, its evaluated properties, material and appearance, its volume in the
document's length unit cubed when the body is solid, and its mass in kilograms when it is solid
and its material has a density. shapeHash is a digest of the features and values that made the
shape: the same in every build that makes the same shape and new when the shape changes, so a
viewer keeps a mesh exactly as long as the shape it shows.
itemKey names the item the part is: 16 hexadecimal digits over its document's id, its part id
and parameters, the declared values it reads (through its features, material, appearance and
properties, and back through the parameters computed from others). A parameter the part never
reads, the configuration that set the values and the document's version are not in it, so a
revision keeps the key and identical parts share it. buildKey adds the document's version, for
caches and editors that must tell revisions apart.
In an assembly build each item is one entry, from its document, and its id is the part's own
followed by its item key, such as post-3f9a1c2e5b7d4e8f: the same item has the same id in every
build, whatever order the components are in. When the build is given several versions of the
document, the first eight digits of the version follow, so two revisions placed together stay two
parts. Tools may show the first eight digits of the key.
A part a design built: its
id,nameand thebodyit is, its shape and per face the names references find it by, its evaluated properties, material and appearance, itsvolumein the document's length unit cubed when the body is solid, and itsmassin kilograms when it is solid and its material has a density.shapeHashis a digest of the features and values that made the shape: the same in every build that makes the same shape and new when the shape changes, so a viewer keeps a mesh exactly as long as the shape it shows.itemKeynames the item the part is: 16 hexadecimal digits over its document's id, its part id andparameters, the declared values it reads (through its features, material, appearance and properties, and back through the parameters computed from others). A parameter the part never reads, the configuration that set the values and the document's version are not in it, so a revision keeps the key and identical parts share it.buildKeyadds the document's version, for caches and editors that must tell revisions apart.In an assembly build each item is one entry, from its
document, and itsidis the part's own followed by its item key, such aspost-3f9a1c2e5b7d4e8f: the same item has the same id in every build, whatever order the components are in. When the build is given several versions of the document, the first eight digits of the version follow, so two revisions placed together stay two parts. Tools may show the first eight digits of the key.