Adobe 12020596 Supplement Manual page 61

Adobe Acrobat SDK
Adobe® Supplement to the ISO 32000
The following algorithm is used to map model space distances for display in 3D measurements for each of
the three sets of units.
The following are default values:
n = 1.0
m = 1.0
Units = "Model Units"
In the algorithm that follows, an entry is defined if it is included in the 3D Units dictionary.
Creation time units – The following is the process creation time units definition:
If is defined, then
TU
If
TSm
If
TSn
Note:
User override units – The following is the process user override units definition:
If is defined, then
UU
If
USm
If
USn
Note:
Display units – The following is the display units definition:
If is defined, then
DU
If
DSm
If
DSn
Note:
Finally, if X is a model space distance and Y is the displayed value, the functional relationship between X
and Y is given by the equation
Units = TU
is defined, then
m = TSm
is defined, then
n = TSn
If either or is defined,
TSm TSn
defined in this case, the unit specification is undefined and is ignored.
Units = UU
is defined, then
m = USm
is defined, then
n = USn
If either or is defined,
USm USn
defined in this case, the unit specification is undefined and is ignored.
Units = DU
is defined, then
m = m * DSm
is defined, then
n = n * DSn
If either or is defined,
DSm DSn
defined in this case, the unit specification is undefined and is ignored.
Y Units = (m/n) * X
Multimedia Features (Chapter 9 in PDF Reference)
9.5.6 Persistence of 3D Measurements and Markups
// a number
// a number
// a text string
should be included in the 3D Units dictionary; if
TU
should be included in the 3D Units dictionary; if
UU
should be included in the 3D Units dictionary; if
DU
.
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is not
TU
is not
UU
is not
DU