CHAPTER 9
812
Multimedia Features
The Daily News
New Planet
Discovered!
FIGURE 9.8
3D annotation positioned on the page
3D Background Dictionaries
A
3D background dictionary
defines the background over which a 3D view is to
be drawn; the entries in a background dictionary are shown in Table 9.41. Cur-
rently, only a single opaque color is supported, where the color must be defined in
the
DeviceRGB
color space. 3D artwork may include transparent objects; howev-
er, there is no interaction between such objects and objects drawn below the an-
notation. In effect, the 3D artwork and its background form a transparency group
whose flattened results have an opacity of 1 (see Chapter 7, “Transparency”).
Note:
An annotation’s normal appearance should have the same behavior with re-
spect to transparency when the appearance is intended to depict the 3D artwork.
This recommendation does not necessarily apply when the appearance is used for
another purpose, such as a compatibility warning message.
TABLE 9.41 Entries in a 3D background dictionary
KEY
TYPE
VALUE
Type
name
name
name or
array
(Optional)
The type of PDF object that this dictionary describes; if present, must be
3DBG
for a 3D background dictionary.
(Optional)
The type of background. The only valid value is
SC
(solid color), which
indicates a single opaque color. Default value:
SC
.
(Optional)
The color space of the background. The only valid value is the name
De-
viceRGB
. Default value:
DeviceRGB
.
Note:
PDF consumers must be prepared to encounter other values that may be sup-
ported in future versions of PDF.
Subtype
CS