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Opening OpenEXR Files 627
• You ca n set the display itself to linear or
logarithmic mode. Logarithmic display remaps
all values greater than 1.0 to a logarithmic
cur ve. The dotted spacing indicators are
supplemented by heavier dotted lines that
indicate when the scale has changed by a factor
of 10. This is useful for most HDR images, as
the HDR data is usually spread out over a wide
range.
• SettingX-AxisScaletoAutomodecausesthe
histogram to encompass the entire spectrum
of the image. If you switch back and forth,
prev ious manually set values are preserved and
restored.
File Loading Parameters group
St or a ge B uf f er Form at —Specifies the format in
which the image data is stored within 3ds Max. The
base types are variations on 8-bits-per-channel
and 16-bits-per-channel integer formats. There
are two forms of each: one with alpha (RGBA)
and one w ithout alpha (RGB). If you are lo ading
an image with an alpha channel but don’t require
thealphadata,choosetheRGBversiontosave
some memory. If you choose a storage type that
supports alpha, but load an image without alpha,
no memory is allocated for the alpha channel;
the loader detects the situation and reverts to the
alpha channel-free storage option with equivalent
RGB bit depth.
The options supports the HDR bitmap
storage options. This allows storage of the
high-dynamic-range data within 3ds Max in three
different HDR formats: 24- and 32-bit LogLUV
formats and 32-bit RealPixel format.
EXR fi les loaded using these storage modes
are suitable for use as environment maps for
reflections and skylight.
Co lor Transform—Because EXR images often
containvaluesbrighterthan“white,”itisoften
desirabletochangetheluminancerangeinthe
source image over which black to white occurs;
that is, to remap the color data. When Color
Transform is on, you can adjust these luminance
and general brightness controls:
Ex ponent—The exponent to apply when loading
the file
Black Point—Where black should be in the
luminancerangeoftheimage
White Point—The white point
RG B Level —A standard multiplier for the RGB data
RGB Offset—An additive offset for the RGB data
Prev iew—The Preview window provides for
interactive previewing of color-transform options
for loading EXR files. After choosing an EXR
file to open, click Preview to enable the preview
window. The image file is loaded into the preview
window, and from then on any c hanges to the
Color Transform options update the thumbnail
in real time.
The preview window ignores the aspec t ratio of
the image to make the most of the small screen
space available.
Plugin About—Opens a dialog that shows
information about the OpenEXR plug-in.
File Info—Opens the File Information dialog (page
3–627),whichletsyouviewfilestatisticsplusany
attributesandchannelsstoredinthefile.
OK —Accepts any changes, closes the dialog, and
opens the image file.
Cance l—Discards any changes and closes the
dialog without loadin g the image fi le.
File Information dialog
This read-only dia log displays basic file statistics
including date, time, size, and resolution, plus any
attributes and channel information stored with