General description

Corona Standalone is a renderer-only application that uses the Corona core to produce images from file inputs. The input format is described here, and Corona for 3ds Max can export it as well. Except for geometry description (which uses binary format and compression for smaller size), the format is textual and human-readable, based on XML.

While currently one has to create the inputs elsewhere and can only use Corona for rendering, we may add some limited editing capabilities to the application in the future.

The application requires activation to work (be it a free 45-day demo, or a full license).

3ds Max export limitations

  • Cannot export 3ds Max native (nonphysical) lights
  • Cannot export 3ds Max native atmospherics effects
  • Cannot export Forest Pack, Multiscatter maps
  • Export of some maps is not supported
  • Some exports slightly differ (for example the noise texture will have slightly different seed)
  • Bokeh custom shape is not supported
  • TODO: is there more?

Command line parameters reference

There are several modes in which you can run Corona, determined by the first command line parameter:

parameter meaning
-? Prints usage help
-confHelp Prints a detailed list of settings for the .conf files (names, types, ranges)
-mtlPreview Starts the material editor preview mode. This is useful for deep integration into a 3rd party application. In this mode Corona reads settings and material config from the standard input, and renders a preview image for the material. This happens in a loop until stdin is closed. In each cycle, 1 (ASCII) float, 2 ints, and a string are read from the standard input before the material definition: [quality] [resolutionX] [resolutionY] [filename] Material definition in the XML format (<material class=“…”>…<material> - see .mtl file description) is then read from stdin until \0 is encountered. The file is rendered and saved to the specified filenames. End of rendering is signalized by writing '.' on standard output. This can be repeated multiple times.
sceneFilename.scn Starts the regular rendering. This is the most common mode - see details below.

Regular rendering command line parameters

The first parameter for regular rendering is always a path to a .scn scene definition file. Any number of optional parameters can follow:

Parameter Meaning
-silent Runs with no frame buffer displayed and does not wait for user to close the window after rendering. Output is only written to files specified with the -o parameter
-c configurationFile.conf Parses an additional configuration (.conf) file on top of configuration files included from inside the .scn file. Any setting values found overwrite the values from previous .conf files.
-o outputFile.jpg Saves the result into a file with given name at the end of the rendering. The file format is automatically determined from the file extension. Currently supported formats are: BMP, PNG, JPG, EXR, GIF, TGA, TIFF, HDR.
-oA outputFile.png Same as -o, but saves the image with Alpha channel. Only some formats support alpha channel.
-oR outputFile.exr Same as -o, but no tonemapping will be applied to the saved image (which is useful when saving high dynamic range images). Can be combined with -oA: -oAR will save the image with alpha, but without tone mapping.

XML input format description

  • All input XML documents must have single root element and must be well-formed.
  • Most names of elements, attributes, materials, … are case-insensitive.

Documentation conventions

Symbol Meaning Syntax
[float] Single floating point value Single number, possibly with a decimal point
[int] Single integer value Single number, decimal point is forbidden
[string] A string value Any sequence of characters (properly XML-escaped if necessary)
[filename] A string holding a file name [string]
[RGB] RGB color value [float] [float] [float]
[XY] 2D geometry vector [float] [float]
[XYZ] 3D geometry vector [float] [float] [float]
[animXYZ] Animated 3D geometry vector (for motion blur) <animatedXyz samples=“[int]”><sample>[XYZ]</sample><sample>[XYZ]</sample>…</animatedXyz>
[TM] Affine transformation matrix (4 columns, 3 rows) written row-wise 12 × [float]
[animTM] Animated transformation matrix (for motion blur) <animatedTm samples=“[int]”><sample>[TM]</sample><sample>[TM]</sample>…</animatedTm>
[map] XML sub-tree defining a map <map class=“[string]”>…</map>
[material] XML sub-tree defining a material <material class=“[string]”>…</material>
[includeList] list of XML nodes defining a set of included or excluded scene nodes Either 1-n <included>[string]</included> or 1-n <excluded>[string]</excluded>
X|Y Either X or Y

Element rules

<tag> Means that the element of type tag must be present exactly once
?<tag> Means that the element of type tag can be present 0-1 times. There is no “?” in the actual file, we just us it as convenient notation.
*<tag> Means that the element of type tag can be present 0-n times. There is no “*” in the actual file, we just us it as convenient notation.
+<tag> Means that the element of type tag can be present 1-n times. There is no “+” in the actual file, we just us it as convenient notation.

File formats

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