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624 Chapter 20: Managing Scenes and Projects
R/G/B/Alpha—
Let you specif y the channels to save:
red, green, blue, and alpha.
Use R ealPixel RGB Data—When on, compresses the
essential data of floating-point color into 32 bits.
For technical informat ion, see S
tructure RealPixel.
Note: Image motion blur is not applied to the
RealPixel RGBA data by the renderer . If you are
using Image motion blur, you will not be able to
save RealPixel unclamped color data.
Exponent—Enables and sets the power function
exponent to use. This is effectively a gamma curve,
but the exponent is presented in an inverse manner
from typical gamma. The default value is what
exrdisplay expects for input.
Pre-Multiply Alpha—When on, the software uses
premultiplied alpha (page 3–997) when saving the
file. Pre-multiplying saves computation time if you
later use this image in compositing.
Plugin About—Opens a dialog that shows
information about the OpenEXR plug-in.
Ex tra Channels and Attr ibutes—Opens a sub-dialog
(page 3–624) that lets you s p e cify additional
information to save with the OpenEXR image file.
OK —Accepts any changes and closes the dialog.
Cancel—Discards any changes and closes the
dialog.
Extra Channels and Attributes
To specify an extra attribute or channel to b e
included in the saved OpenEXR fi le, click the
corresponding + button and then choose the
attributeorchannelfromthelist. Todeletean
attribute or channel, high light it in the list and
then click the corresponding X button.
General Notes on Extende d Attributes and
Channels
Please note the following:
• You can view the extended information via the
File Info button on the input dialog.
• A default File Tag s tring is provided when you
add an attribute/channel. You can change the
file tag by highlighting the entr y in the list and
theneditingtheFileTagfieldimmediately
below the list. You can also enable and disable
the attr ibute/channel with the check box to the
left of the File Tag field.
Note: Each saved attribute or channel must
haveauniquefiletag.Ifyouspecifymultiple
instances of a file tag, only the first attribute or
channel with that file tag is used.
• AllthecurrentattributesareStringtype
attributes that are stored in the header for
the file, and can be read in plain text via the
exrheader.exe utility (available from t
he official
Website >Downloadspage).
• Attributes and channels are stored in the file
in alphabetical order according to the ASCII
file tag.
• While this plug-in can write most of the
3ds Max G-Buffer (page 3–946) channels, there
is no software that can utilize them yet.
• Attributes and channels are identified by
plain-text (ASCII) strings. There can be
only one instance of a string tag in an y file.