Indigo Renderer

Indigo is a formerly free, physics-based rendering engine for generating photorealistic images. It is the pure render engine - the creation of the scene must be done with the help of other products and are exported to Indigo.

Indigo version 1 is free for both private as well as for commercial use, but not free software. As of version 2 is marketed commercially.

A great advantage of indigo over many other render engines is that it is possible to finish a rendering process and continue later. The tool needed for this is called " Indigo résumer ". Indigo résumer is not required but provides a GUI for the corresponding command line commands dar. Newer versions of Indigo allow pausing and resuming of renderings, directly in Indigo.

Technology

Indigo is different from many other rendering systems in the fact that he only Metropolis Light used to solve the rendering equation transport. In this way he does not need the definition of radiosity or photon mapping, and produces absolutely realistic illustrations. The price of this method is the low speed of rendering. The image is not calculated line by line, but built on the principle of Monte - Carlo simulation. At the beginning creates an extremely gritty liges image which is constantly refined in the further course. Indicative of this method is the fact that the actual rendering process never reaches a designated natural end. The rendering process is then aborted by the user if the image satisfies its quality requirements.

By supporting functions such as Spektrallichtberechnung, a virtual camera model, physical sky and more Indigo is able to produce more realistic rendering results than conventional GI ( Global Illumination ) raytracing renderer.

Indigo requires no parameters like GI passes, AO ( Ambient Occlusion ) - runs, AA ( antialiasing) - runs, soft shadows or complicated lighting setup to produce extremely realistic results. For advanced users, however, options are available to fine-tune the rendering performance available.

Further processing

It is possible that the Indigo incurred when rendering raw data into a separate file with the file extension ". Igi " stores, so you can continue later the process, as already mentioned above.

However, one can also use this data, ' further process the image with the offer on the Indigo site "Violet Tone Mapper ". Here, the noise can be subsequently weakened slightly as realistic-looking glare and lens effects or added. Also the distribution of brightness and white balance can be changed (see tone mapping ).

In the newer versions of Violet Tone Mapper, exclusive histogram and Noise Reduction already available internally, what the tone mapping simplified. In addition, give so-called "Light Layers" the ability to create individual light sources or light source groups into separate levels and to be able to adjust during rendering in color and intensity, the backlight ( Sun & Sky Background Light or EXR ) is always at level 0. However, it should be noted that each Lightslayer rather increases the RAM consumption.

Material Settings

In Indigo, there are eight freely selectable material types that can be influenced by a variety of parameters in turn. { Update needs: through the " ISL " ( = Indigo Shader Language ) materials and emitter were generalized ( = light sources ) and can now be used fluently. Only "Exit Portal" is still a stand-alone material. However, the ISL is still in its infancy and most Exporter they have not yet been incorporated into their repertoire function. }

The types are:

  • Diffuse - an object with this material has a matte finish.
  • Oren - Nayar - an object with this material has a rough surface.
  • Phong - an object with this material reflects light differently highly directional, ie either as a mirror or as duller metal. For example, the base surface of the right image has a very diffuse Phong material mixed with a diffuse material.
  • Specular - an object with this material can be transparent. Is it transparent, there is a choice between transparency with or without subsurface scattering.
  • Glossy Transparent - this material is transparent and has a rough surface, the choice between transparency exists with or without subsurface scattering.
  • Diffuse Transmitter - an object with this material has a matte surface and is translucent.
  • Blended - here two materials can be combined. For example, you can mix in a matte material still 30 % gloss material, as is done in the green object in the right image.
  • ZERO - An item with this material is absolutely invisible. Alone it really has no meaning, but together with another material (via blend) it has some applications, such as clip mapping.

In addition, there are two other types, but not (yet) belong to the materials:

  • Emitter - an object of this type radiates light behaves like a luminous body. Example: The red ball in the right image is an emitter.
  • Exit Portal - an object of this type, usually it will be a tarp can sun like a window into the scene appear, but when light hits from the scene on this object, it is treated as if it had left the scene forever, is thus not calculated. This has the advantage that compared to a single hole in the wall, wherein the light has to be based on the passage through the hole further long, speeds up the rendering process. In general, however, one will only use this object when the opening is not in the camera view to the outside.

It is also possible to make use of a number of preset materials as materials. These materials are available as files in the \ nkdata \ folder of the Indigo installation included (example: Ag.nk for silver ) " nk ".. With them, all the properties of the material such as color or refractive be defined, but not the " exponent " setting, so the variable that distinguishes between a matte or reflective material. Thus, this variable must also be specified. Link to list of all NK - material ↓

Transparent NK materials (for example H2O.nk = water or DIAM.nk = diamond ) can not be displayed correctly. Only the reflections have the right color. An object with these materials appear black. To absolutely physically correct representation of transparent materials or for more precise color definition, eg from diffuse materials, one can use the so-called " Tabulated Spectrum" as an alternative to the standard RGB input. Here are the highest and lowest wavelength and the number of values ​​are given in meters between them. The starting point is linearly distributed measurements. Then amplitude peaks are entered. For all RGB data one can use the Tabulated Spectrum, to allow even more accurate information for SSS can be made.

Export modules (excerpt)

For several 3D graphics applications, there are export modules according to Indigo or in the file format used by Indigo " igs. "

  • Blender:
  • " Blender Exporter Script" for Indigo 0.6
  • " Blendigo " for Indigo Indigo 0.9 and 1.0 in the forum
  • Max by Indigo
  • Sketchup by Indigo
  • Cinema 4D by Indigo
  • XSI by Indigo
  • Maya to Indigo

( Sort by Download Number of Exporter )

The ". Igs " files use the markup language XML and are therefore easy to write in principle by hand or edit.

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