The functionality of ART is explained in detail in the ART Handbook. Here, we just give a brief overview of the seven executables plus the resource directory which are installed when ART is built.

  • The main renderer: artist
    This application takes scene files in .arm format as input, and yields displayable images as output. It performs all the steps of image synthesis: reading a scene, preparing it for rendering, path tracing (which yields a spectral HDR image in .artraw format), and tone mapping. In normal operation, artist does not delete the generated .artraw file, so that the resulting image can be further analysed and tone mapped.
  • The tone mapper: tonemap
    Mainly does what it says on the tin: it takes .artraw images as input, and turns them into either .exr or .tiff files for display. But in addition to classical tone mapping, tonemap can also extract spectral slices from .artraw images, and even “explode” a polarised .artraw into its spectral Stokes components (which yields a lot of .exr files).
  • The polarisation visualisation tool: polvis
    For .artraw images which contain polarisation information, this app offers a variety of visualisation functions which are described in one of our publications.

  • The difference image generator: bugblatter
    For two colour input images, this app generates a false colour difference image according to the CIEDE2000 metric. Separate diff images for luminance, chroma and hue can also be generated. For spectral .artraw input images, it can also generate a plus/minus difference image for a given wavelength. The difference image can also be stored in the ART-specific lossless floating point single channel .artgsc format, for further processing via greymap.

  • The image file manipulation tool: art_imagetool
    Utility for the proprietary image formats of ART, .artraw (spectral) and .artcsp (colour space). Functions offered are computation of SNR and diff values of two images, addition of two images, plus re-scaling of single images and querying of individual pixel values.

  • The .artgsc display tool: greymap
    A tool to convert floating point single channel .artgsc images into displayable false colour or greyscale images. It offers a few options more than bugblatter for the formatting of .artgsc output, and mainly exists as a separate app because .artgsc images were, at various points during development, used as debug output for certain subsystems.

  • The scene file translator: arm2art
    This tool translates the human-readable .arm scene file format of ART to the parseable internal .art format. artist automatically translates any .arm file it is fed, but this tool allows one to perform translations without having to invoke the actual renderer.

In addition to these seven executables, a resource directory called ART_Resource is installed. Where it is installed depends on your system type: on MacOS, it is usually placed in ~/Library, under Linux in ~/lib (if you chose to install ART in your home directory, that is). The directory contains:

  • Spectral reference data, including Macbeth Color Checker and Munsell Book of Color reflectance data
  • Luminaire data for CIE reference lamps
  • Properties of a number of materials, such as certain metals, and glass types
  • ICC profiles for various RGB spaces
  • But also internal machinery needed for the arm2art file translation machinery.