This is the tool that can be used to convert a variety of image files to tiled multiresolution .exr files in OpenEXR format. The resulting tiled OpenEXR textures can be used in V-Ray for 3ds Max through the VRayHDRI texture, or directly in V-Ray for Maya, Modo, and V-Ray Standalone.
The Image to Tiled Multiresolution EXR Converter can be opened from Start Menu > Programs > V-Ray for 3ds Max > Tools > Tiled Multiresolution EXR Converter.
Start the img2tiledexr executable from C:\Program Files\Chaos Group\V-Ray\host application\bin\
Supported input image formats are:
V-Ray image file (*.vrimg)
Portable Network Graphics (*.png)
Windows bitmap (*.bmp)
Targa image file (*.tga)
Radiance HDR image (*.hdr)
Silicon Graphics (*.sgi, *.rgb, *.rgba)
JPEG image file (*.jpg, *.jpeg, *.jpe)
OpenEXR image file (*.exr)
Softimage PICT file (*.pic)
Tagged image file format (*.tif, *.tiff)
Running img2tiledexr without any parameters, or from the Start menu, will open the GUI version of the tool as seen above. The GUI allows you to convert one or a number of image files to tiled multiresolution OpenEXR files.
Pixel type – Specifies whether the data in the .exr file is saved as 16-bit or 32-bit floating point numbers.
Compression type – Sets the compression type, choosing between the several available methods. If not specified, the ZIP method is used.
- RLE - run length encoding
- ZIPS - one scanline at a time
- ZIP - in blocks of 16 scanlines
- PIZ - piz-bazed wavelet compression
- PXR24 - lossy 24-bit float compression
- B44 - lossy 4x4 pixel compression, fixed rate
- B44A - lossy 4x4 pixel compression
- DWAA - lossy DCT based, blocks of 32 scanlines
- DWAB - lossy DCT based, blocs of 256 scanlines
DWA compression level – A floating-point value that controls the compression level when using the lossy DWA compression methods.
Linear – Specifies if the input image should be converted from sRGB to linear color space when saved into the tiled OpenEXR file. Possible values are: off (no conversion), on (convert colors from sRGB to linear space), auto (convert all images except .hdr and .exr files).
Color Mode – Specifies whether to create a color EXR file (with RGB channels) or grayscale EXR file (with Y channel). When set to Auto, the image can be checked if it actually contains alpha and/or color data, and the output channels can be optimized, writing only the needed channels.
Tile size – Sets the dimensions of a squared tile.
Conversion type – Selects the type of conversion to be performed.
- Single file – Only a single file is converted.
- Multiple files – Multiple files are converted at once.
Input file – Specifies the image file when Single file is selected as the Conversion type.
Input dir – Specifies the input files' directory when Multiple files is selected as the Conversion type.
Output dir – Specifies the output directory for the tiled .exr files when Multiple files is selected as the Conversion type.
Wildcard – Specifies a search pattern for the input file names. Wildcards (*) can be used to define the pattern.
Subdirectories – When this option is enabled, all image files contained in subdirectories of the specified input directory are also converted.
Convert – Starts the conversion.
Command Line Usage
There are three methods for running the img2tiledexr from the command line:
If you type just
on the command line, this is the same as double-clicking the file.
Converting a single image file to a single .exr file:
> img2tiledexr <image_file> <exr_file> [options]
In this case, the <image_file> cannot contain wildcards. Note that the .exr extension is not added automatically to the output file name.
Converting multiple image files to multiple .exr files:
> img2tiledexr <image_wildcard> [output_dir] [options]
In this case, <image_wildcard> can contain the wild-card symbols '*' and '?'; the image files will automatically be converted to OpenEXR tiled multiresolution files with the .exr file extension. Optionally you can specify in <output_dir> the directory of the output files. If not specified, the output files will be written to the input directory.
Caution! Under Linux and OS X parameters with wildcards must be enclosed with apostrophe symbols - 'image_wildcard'. Otherwise the command line shell will expand automatically the wildcard into file list, which will force the program to terminate.
In all cases, the original image files are not deleted.
Postfix "_tiled" will be added to the file name in case you use wildcards.
Note that many applications expect the colors in OpenEXR files to be in linear color space rather than sRGB/gamma 2.2 color space.. For this reason, img2tiledexr automatically converts the colors in the input image from sRGB to linear space for all image file formats except .hdr and .exr images. You can use the -linear option to control this conversion.
One or more of the following options may be specified:
|-32bit||Stores the floating-point data in the .exr file as 32-bit floating point numbers. If this option is not specified, the data is stored as 16-bit floating point numbers.|
|-compression <method>||Sets the compression type for the resulting .exr file. If not specified, ZIP compression is used. Currently supported values for <method> are: none, rle, zips, zip, piz, pxr24|
|-tileSize <size>||Set in <size> the dimension of a square tile. If not specified, the default tile size is 64x64.|
|-linear <mode>||Specifies if the input image should be converted from sRGB to linear color space when saved into the tiled OpenEXR file. Possible values are: off (no conversion), on (convert colors from sRGB to linear space), auto (convert all images except .hdr and .exr files).|
|-subdirs||When using wildcard, this option makes img2tiledexr to search the subdirectories of the specified one.|
|-help||Print the help message.|