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Hello people I thought I would get the latest Blendigo wiki underway. Already we are at Indigo/Blendigo version 1.0.8 and there is a lot of new functionality to document. Please feel free to add more detail or improve/correct anything you see while reading. Dont worry about your spelling etc if English is not your first language I would rather we get the content in and then it can be tidied up afterwards. The aim is to provide fairly comprehensive but easy to read information for people with existing Blender skills to pick up using Indigo. Thanks. (BigFan) Blender 2.45 to Indigo 1.0.9(stable) using Blendigo 1.0.9

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Introduction

Indigo is a renderer still in mid development. Some aspects are incomplete or a little unpolished, as are the scripts written to be exporters. Even so if you take time to learn the ins and outs of what is available and how to use it properly you can produce terrific results. There are many fine renders in the Gallery already that attest to that and the skill of the people who made them.

As with all rendering it is the attention to detail and correctness that produces the most satisfying and convincing results. Extra time spent finding the best textures say, or refining the lighting pays off in the image. In the case of Indigo a sound grasp of the technical basis also brings rewards because the nature of an Indigo render is to model the path of light in a physically correct sense.

We hope this wiki page will familiarise you with the features and requirements of Indigo and how to best use Blender to set up your scenes. Along with that content are some hints and insights into what doesnt work and why and (hopefully soon) some .blends showing some typical situations - for instance, modelling wine glasses or using portals.

If anything mentioned here is unclear feel free to post questions to the forums. Remember there is a search facility available to help you find previous and similar questions and discussions.

Installation

For Windows users

Python

Although Blender comes with a subset of Python having a full Python install is required for many Blender scripts. A full install of Python is required to run the Blendigo script. You need to make sure you have the correct version for the script version you have. Python 2.4.4 is used by earlier versions of the Blendigo made for Indigo releases up to v0.8 and Python 2.5.2 for the most recent Indigo v1.0.9(stable) external link to Python homepage

Blender

A standard install of the latest Blender version is fine for Indigo purposes - currently 2.45.external link to Blender downloads

If you are in the habit of trying out SVN builds of the next Blender version please be aware that from time to time the python API has revisions and the existing Blendigo script may not function without some modifications.

Usually it is best to stick with the recommended set of Blender, Indigo and script versions.

Indigo

Indigo has no special requirements for installation. You may extract the file to a convenient location. If it is handy to your Blender install thats useful.

Note: Linux builds and 64 bit Windows builds are only available for stable releases. (Prior to v1.0.9 the 64 bit builds of Indigo did not have .exr support.)

Blendigo

Place the Blendigo script in Blenders scripts folder. If you installed Blender to the default location go to C:\Program files\Blender\.blender\scripts\

Place the Indigowrapper.conf in the bpydata folder Again if you installed Blender to the default location go to C:\Program files\Blender\.blender\scripts\bpydata\

You will need to open the wrapper in Notepad and edit the path to the Indigo.exe folder.

Note: You need to use a Blendigo script version matching the Indigo version. For instance Blendigo 1.0.9 is made for Indigo 1.0.9

This is because Indigo and the exporter script are evolving together and not only are new capabilities added but some of the existing ones are changed or even removed.

Additional note: This wiki documents the python script used to export from Blender to Indigo known as ‘Blendigo’. This script was the first available for general use and has been updated and refined by various contributors with each new release of Indigo.

Blendigo is not the only Blender2Indigo script available however. If you search the Blender section of the Indigo forum you will find a few by different coders. Some are slightly different/better than others in some ways but essentially they do the same job.

Much of the information and hints detailed here is applicable to those scripts as well but the UI in each case may be arranged differently. To download the alternative scripts and find explanations of their respective capabilities see the first post of their threads.

Additional installation help

flash_tut.jpg There is an introductory video tutorial (Flash format) covering installation available from this site under Documentation/Indigo Tutorials/Blender. The Indigo version shown is 0.8 stable but the content is still applicable for this release.link to tutorial downloads

Please note that if English is not your first language there are people visiting the forums who may be able to assist you in your native language. Try posting your questions to the ‘Language Forum’. Currently we have members able to help in Italian, Russian, Dutch, Spanish and French.Language Forum

For Linux users

coming...

In the meantime see this forum thread Tutorial:Blender+Indigo Under Linux

Practical aspects

Hardware

While Indigo can be used on practically every desktop or laptop rendering with this method is very calculation intensive.

Producing a reasonably noise free render of a simple scene at 800x600px with a 1gb,3gz Pentium might take say 12-24 hrs depending on the materials.

Ideally you should invest in a recent quad core machine or set up a small network (see section below) for rendering more than experimental work. A quad at 3.66ghz will be > 10x faster than a single 3ghz Pentium.

More complex scenes and/or of a large size can take a long time to render even so. A useful indication of the degree of image refinement or clarity obtained is the number of iterations/pixel done. Typically you would not be happy with say 1000 mut/pixel (the Indigo UI displays the figure in progress) although you could ‘cheat’ a little at this level by using a noise reduction program like Neat Image, Noise Ninja or Noiseware to remove the more obvious pixel dust at the cost of some detail.

More likely people will call a render finished at 3000 mut/pixel. You could go on rendering for as long as you wanted but somewhere is a balance between getting the job done and the difference being not really discernable. Purists would probably finally give in at 6000 mut/pixel and addicts should be stopped at 12000 for their own good.

Memory use

Windows XP 32 bit can address 4gb of memory however it will only let you use 2gb of memory for applications and keep the rest for itself. Actually in use the memory available will top out at about 1.6 gb regardless of your installed RAM. Sometimes this is not enough to get your mission done.

It is possible using Blender and Indigo that this situation will arise in 3 ways.

1. you have a very large scene to deal with in Blender and put through the exporter -say more than a million faces and perhaps in a thousand meshes. 2. the .igs file exported is very large for Indigo to open - approaching 2 million faces. 3. the rendered image in progress is large -in the order of 2400×1800- and has complex materials.

The alternatives are to move up to 64 bit which will address a much larger space or if you have XP Professional -32 bit- to use the 3gb switch to extend the usual limit. This switch will allocate another gb to applications at the expense of the OS. In reality the 3gb comes down to about 2.7 gb or a little bit more with a further tweak. The good news is that this is the limit even if you have say 1.5 gb of memory. There may cause some disk paging however.

To enable the 3gb switch in Windows XP Professional requires an edit of the boot.ini file and choosing that ‘OS’ at start up. Vista is slightly different. You need to be aware of what you are doing with this. You can find further details in the section ‘3gb switch’ topic.

The applications you run with the switch need to be built with the 3gb capabiltiy enabled. There is a 3gb aware and optimised build of Blender 2.45 available at graphicall.org A better way around the memory limitation is to chain together smaller .igs files as ‘includes’.See ‘Includes’ topic for a fuller description. This means you can export your scene as a number of related files - most easily different layers. Indigo will open these sequentially which is much kinder memory wise. Unfortunately though this strategy this will not assist with issue 3.

If you are in the position of needing large renders for print or because you want to then down size the image to eliminate ‘jaggies’ you will need to go the way of 64 bit. Presently Indigo 32 bit is not enabled for the switch however hopefully this will be remedied soon. It also should be said if you are producing large renders you really need to be doing this using networked computers or quad processors and even then you will be waiting quite a while for a reasonably noise free image.

3gb switch

NOTE THIS IS A DRAFT DOCUMENT PLEASE DO NOT FOLLOW THE 3GB INSTRUCTIONS UNTIL THE WIKI HAS BEEN CHECKED FOR ERRORS OR OMISSIONS

32-bit XP Professional: You need SP2 for this because otherwise you need to apply a MS hot fix first - only available from MS on request. Note that some device drivers may not be happy with the change and in this case is it easier to abandon the idea of using the switch. To enable the 3GB switch in Windows XP Professional proceed as follows. You need administrative rights.

Right-click My Computer. Click Properties. In the System Properties dialog box, click the Advanced tab. On the Advanced tab, under Startup and Recovery, click Settings. In the Startup and Recovery dialog box, under System startup, click Edit. The Windows boot.ini file will be opened in Notepad. Save a backup copy of the boot.ini file on your computer, in case you need to revert back to the original version of the file. Note: The contents of the Boot.ini file may vary from computer to computer. Select the following line in the boot.ini file:

multi(0)disk(0)rdisk(0)partition(2)\WINDOWS=”Microsoft Windows XP Professional” /fastdetect

Copy (Press CTRL+C) this line and paste (Press CTRL+V) it immediately below the original. Note: Your string may be different from the string shown. Be sure to copy the string from your boot.ini file, not the string shown here. Modify the copied line to include “ /3GB”, as shown in the following example. Note: Do not overwrite any existing lines.

multi(0)disk(0)rdisk(0)partition(2)\WINDOWS=”Microsoft Windows XP Professional 3GB” /3GB /fastdetect

Save the boot.ini file and exit Notepad. Click OK to close each dialog box. Restart your computer. During startup, select the 3GB option. If you do not select the 3GB option, the system will default to the 2GB memory setting.

There is an additional tweak you can add that will enable slightly more memory than the 2.7gb yielded by the switch as described and that is to add /userva=2900 after fastdetect so:

multi(0)disk(0)rdisk(0)partition(2)\WINDOWS=”Microsoft Windows XP Professional 3GB” /3GB /fastdetect/ userva=2900

32-bit Vista: There is no boot.ini under Vista. To enable the same functionality proceed as follows. You need administrative rights.

Right-click Command Prompt in the Accessories program group of the Start menu. Click Run as Administrator. On the command line, enter “bsdedit /set IncreaseUserVa 3072” Restart the computer.

To turn off the 3GB switch on Windows Vista. Right-click Command Prompt in the Accessories program group of the Start menu. Click Run as Administrator. On the command line, enter “bsdedit /deletevalue IncreaseUserVa” Restart the computer.

Factors to consider for best performance

pocket_watch.jpg To get the most rendering performance out of Indigo on your pc you should consider:

  1.
     setting the display and save periods quite high because these take up valuable calculation time.
  2.
     alternatively using the console version of Indigo (which doesnt display the render in progress).
  3.
     tweaking the renderer parameters and type to suit the scene and situation.
  4.
     keeping the lighting fairly simple - including a fairly simple .exr map if used.
  5.
     not having unnecessary geometry laying around outside the general camera view.
  6.
     avoiding calculation intense materials like subsurface scattering if it is not that important.
  7.
     rendering your image in one hit rather than saving an .igi as well as the .png for later resuming.
  8.
     making use of exit portals where appropriate

Mesh preparation in Blender

Layers

Only Blenders visible layers will be exported. This can be handy if you want to exclude(hide) some meshes from your scene.

Normals

The best way to mark your Blender mesh normals suitable for Indigo interpretation is to use an Edge Split Modifier.Using a split angle of somewhere about 25 degrees works well in many situations. This is much easier than separating a mesh along creases or hard edges although you could do that. Without marked normals Indigo will render geometry as rounded where you don’t want it. This will make ugly renders around sharp edges and holes and will most likely show up the triangular faceting of the mesh.

The direction of normals is of considerable importance to Indigo. Without the correct orientation Indigo’s render will show black faces similar to that of Blenders internal render when they are wrong. If you are getting a render that is unexpectedly black in parts then this is most likely the reason.

In edit mode from the ‘Mesh/Normals’ menu either use ‘recalculate inside/outside’ or ‘flip’ to fix the issue. You can see the normals in the 3d window as blue lines by enabling ‘Draw Normals’ in the editing window (F9)- ‘Nsize’ draws them longer. You may need to ‘Tab’ in and out of Edit mode for the display to update.

Smoothing

Make use of Blenders Set Smooth and Auto Smooth to identify your meshes for smoothing in conjunction with the Edge Split modifier for edge marking. Apply a Subsurf modifier level if required.

Error checking

Indigo has some built in error checking for problem geometry that will prevent a render from proceding if found. The most likely issues to arise will stem from ‘doubles’ and other stray lines and vertices in your Blender scene. If you get a warning from Indigo about ‘degenerate triangles’ or ‘normal was not a unit length’ suspect that your scene has warped or rogue bits somewhere. Use Blenders ‘remove doubles’ function or ‘clean meshes’ script in edit mode to tidy up.

General reminder: don’t forget to ‘apply scale and rotation’ ( Ctrl+A ) to your edited objects...

UV mapping

Indigo’s texture and bump mapping rely on the co-ordinates generated by Blenders UV mapping. The UV mapping in Blender is very effective.If you need to familiarise yourself with the tools I suggest you go here external link to Blender Manual/Unwrapping a Mesh

Briefly: Open an Image Editor window ready to map into, switch to UV Face Select mode in the 3d window, select the faces you want to map and unwrap them, then load a texture file into the Image Editor window, and map/position the vertexes to suit. The exporter will export the texture/bump-tags and UV co-ords sets into the Indigo XML, and the texture/bump-map should appear correctly on the object during rendering. The image format you use should be .jpg

Once done this, you can open the Blendigo script, select your material, assign a material type to it (for example Phong), then click on the three-dots button on the far right of the Albedo texture filename text field, and choose your texture. Follow the same process for a Bump texture if you want to load a bump-map.

In general you needn’t be concerned about the A,B,C parameters for the maps but for Bump maps the height of the bump is controlled by the B field. Typically this would be set to 0.001

In the case of exponent maps you want to set A to 0, C to what you want the minimum exponent to be (must be greater than 0), and B to the maximum exponent you want keeping in mind that C will get added to it:

So lets say you want to use the exponent map to range between an exponent of 50 and an exponent of 100. You would set A, B and C accordingly: A = 0 B = 50 C = 50

This means that RGB 0,0,0 in texture map will equal 50 exponent and RGB 255,255,255 in texture map will equal exponent 100.

Note about texturing:

The image formats supported by Indigo are: png, jpg, bmp, tif, and tga. The image needs to have 3 or 4 channels of either 8 or 16 bit depth i.e. 24, 32, 48 and 64 bit images are supported. The channels either are Red, Green and Blue (RGB), or Red, Green, Blue and Alpha (RGBA). The Alpha channel is ignored.

Please note that Arroway textures are single-channelled. You need to convert them from greyscale to RGB to use them in Indigo.

Arrays and Instancing

Blendigo supports Blenders array modifier and is compatible with Indigo instancing. Only the original mesh is exported along with information of scale and position for the rest.

Softbodies, Sculpt and Cloth*

The softbody and sculpt tools produce meshes that can be utilised in Indigo. In the case of sculpt beware the number of faces made because Blendigo will choke on a large mesh. You can break up your mesh into smaller pieces to get around this limitation.

  • The new cloth simulation coming in Blender 2.46 has the facility to add cloth to the modifier stack. If the modifier is applied the simulation will be removed but the deformed mesh will be frozen at that particular frame. This should make very realistic draped fabric etc for a render.

Particles

Blender particles are not supported at this time. You can however parent an object to the particle emitter after setting up the generation to create a cloud of similar (dupliverted) objects following the rotation of the particles. You can make these dupliverts real (Object/Clear Apply/Make Dupl Real) at a particular frame if you wish for further individual treatment and to make the emitter visible but at the loss of particle based editing and animation. external link to Blender Manual/Particles

Fluids simulation

Blenders fluid simulation is supported and can be rendered as an animation. You need to make sure though not to select the ‘separate meshes’ option else your renders will be completed all showing the same frame(mesh). For some ballpark settings try: Making the fluid simulation Resolution fairly high - something like 100 or 150. In the Realworld-size select a physically correct size. In the Domain/boundary options set: surface subdiv 4 tracer particles 10 generate particles 1 surface smoothing 1

Artful diversions?

discombobulator.jpg Of course you need not be limited to standard Blender when it comes to making geometry to use in your scenes. Some of the Python scripts available For Blender can produce interesting geometry to render in Indigo.

   *
     Discombobulator script (available in Blender while in Edit mode): An old favourite for making a greebled object.
   *
     Demolition script: Although this script is still a wip it has the capability to bake demolitions. You will need to download the latest version from the development thread and read the manual that comes with it. external link to Blender Artists/Python&Plugins/Demolition thread

sculpt_generator.jpg Blender will import .obj, .vrml, .3ds, .stl etc. files too so you can use bits made in other applications like:

   *
     TopMod external link to homepage
   *
     Scherk-Collins Sculpture Generator external link to berkley.edu page

or for something a little more practical:

   *
     An Ivy Generator by Thomas Luft external link to homepage

Blendigo UI

Material editor

Convert

The convert button enables a material set in Blender to be converted into an Indigo one. It is not necessary to use this to set your materials in Blendigo but can be useful to load pre-existing colours etc. In the past this was useful to interpret materials in scenes set up for Blenders internal renderer but now it is somewhat redundant as people tend to use the script to set Indigo options directly. For a description of which Blender material parameters equate to Blendigo materials refer to the Blender 2.4 /Indigo 0.5 tutorial.

You should set your RGB whites to <0.8 because it is the nature of Indigo that it takes a lot longer to resolve (render) the bouncing light when higher.

Note: When you save your .blend with the script loaded all of the script settings are saved with the file.

Previews

The previews button will launch Indigo with a simple scene to render the material currently in consideration. The image size and settings have been selected to produce rapid results over quality. You can end the render of the preview any time by closing the UI window. If you allow it to run on it will save images to the ‘renders’ folder as per usual. There are a few options for the scene available, accessed in the menu above the preview button, including a sphere, a cube and of course Suzanne(monkey). You may add your own custom mesh if you like by replacing an .xml in the ‘previews’ folder with yours but there is a little bit of editing to do regarding paths as well so that it will work correctly. The preview function isn’t available for emitters.

Material types:

1. Emitter

peak_spectrum.jpg The emitter material option provides for irradiating meshes. It is not really a ‘material’ as such but has been incorporared into the script this way for convenience. There are 4 options for describing the emission directly and a further option to use Photometric data (IES profiles).

  1.
     as simple ‘RGB’ values
  2.
     as ‘peak’ using nm curve data
  3.
     as ‘blackbody’ using degrees Kelvin
  4.
     as ‘uniform’* using spectral radiance values. *currently not implemented in Blendigo.

In each case you can set the strength of emission using ‘gain’ or enter real world data under the ‘Efficacy scale’. The power and efficacy entries of a few common light sources are listed here (ex Wikipedia):

neon.jpg Category Type Overall luminous efficacy (lm/W) Combustion candle - a nominal 40 W 0.3 Incandescent 5 W tungsten incandescent 5 40 W tungsten incandescent 12.6 100 W tungsten incandescent (110V) 16.8 100 W tungsten incandescent (220V) 13.8 quartz halogen (12-24V) 24 Fluorescent 5–24 W compact fluorescent 45–60 34 W fluorescent tube (T12) 50 32 W fluorescent tube (T8) 60 36 W fluorescent tube (T8) up to 93 28 W fluorescent tube (T5) 104 Light emitting diode 5 W white LED 22

Note: The ‘power drawn’ is over the whole emitter surface, not per unit area. So a bigger mesh area or a scaled one with the same setting means comparatively less light output as seen by the observer. For ‘uniform’ emitters the spectral radiance values to use will be quite large - say 10^8.

flash.jpg Flash: To simulate light from a flash unit in your render use a very small emitter plane (1cmx1cm) with a high efficacy and power. This makes for sharp shadows. Electronic flash has a colour temperature of 6000K. If you want your flash model to be to be a little more accurate use a 1cm cube and remove the front wall. Separate the back wall for the emitter and give the other 4 faces a black diffuse material.

Photometric data (IES profiles)

ies.jpg

Indigo can make use of IES profiles to describe the light distribution of a particular fitting such as a downlighter. These profiles are made available by lighting manufacturers and utilities exist to view and modify them if required. Blendigo comes with a small collection of IES profiles but of course Indigo can utilise many others.

Here are some links to examples of a manufacturer’s data. external link to ERCO IES for download external link to Lithonia Lighting IES for download external link to Simes IES for download

At present Indigo will only handle distributions facing away from the normal. That is it cannot use a profile where light shines both forward and back simultaneously or an error will occur.

To make a light in this manner you need to create a small plane in your scene, say 200 mm square, to locate the light source in space, and then give it an ‘Emitter’ material. Associate your mesh with an IES profile via the file selector.

Presently there is no way to change the light output of a profile as for instance a dimmer might however for workarounds you can either:

  1.
     if Reinhard tonemapping is used, make the other lights brighter. This will result in the IES light appearing relatively darker.
  2.
     modify the IES profiles in IESgen3 (see the Utilites section below) or manually in Notepad.

2. Diffuse

A Lambertian diffuse material, is the simplest of all Indigo materials. ‘Diffuse’ can be used for walls, paper, rough plastics etc where there is no reflection. To set a material as Diffuse, first select the mesh in the Blender window, then select “Diffuse” from the materials drop-down menu. Control the <colour> value by using the colour mixer. This material can have texture and bump maps applied.

mat_diffuse2.jpg

example of Diffuse XML:

<diffuse>

 <albedo_spectrum>
   <rgb>
     <rgb>1 0.2 1</rgb>
       <gamma>2.2</gamma>
     </rgb>
 </albedo_spectrum>

</diffuse>


Diffuse transmitter

diffuse_transmitter.jpg With this option enabled Indigo will use the nominated diffuse texture as a transmitter. The colour mixer values are ignored by the script when exporting.

This material is a very simple BSDF that basically scatters incoming light into the opposite hemisphere. Although it doesn’t really have any exact physical basis, it could be thought of as the limit of many sub-surface scatters inside a thin, highly scattering material. It’s meant to be used on single-layer geometry. The material is a lot faster than using SSS. Because of this people have cleverly used diffuse transmitters to cut corners in their renders especially in situations where they anticipate the geometry and SSS materials might take a very long time to produce a noise free image.

It is useful for simulating materials for curtains, lampshades ,paper, leaves etc. You could also use a diffuse transmitter to show an image on a television or a computer screen. It will generally be a good idea to blend this material with a normal diffuse or phong material, so that some backscattered light is visible, not just transmitted light. The diffuse transmitter only transmits light - it doesn’t reflect it.

You can also use it on objects with volume. But the effect is completely different. Whereas SSS on a sphere, for instance, will make it look solid, a Diffuse Transmitter will make it look like an empty transluscent balloon. A downside against SSS is that you cannot adjust the scattering value as it is set at max by default. Instead you can adjust the degree of translucency by blending the material with an opaque diffuse or phong material and playing with the blending ratio.

The amount of transmitted light of a diffuse transmitter is controlled with a texture. If the transmittance is too contrasted you can increased the ‘B’ value of the texture map to make the transmittance more uniform. ‘A’ should be zero.

As it’s not possible to use a texture on SSS materials blending a diffuse transmitter with one is a work around. See also the Blended entry below.

3. Oren-Nayar

oren_nayar.jpg The Oren-Nayar BRDF models very rough surfaces, such as clay, the moon, sprayed concrete etc... It differs from a Lambertian Diffuse BRDF in that it has more back-scattering. The sigma parameter is a roughness parameter that controls the amount of back-scattering. See the picture for an illustration of the effect.

4. Phong

Phong is a physically based glossy reflection model using a Phong lobe. It has a lambertian diffuse substrate. The material can be texture and bump mapped. This material can be used for metals, shiny & rough plastics, carpaint, etc... It has perfect reflection at its most glossy setting of 1 million.

Phong can optionally use a nkdata complex IOR file (lab measured) to reproduce realistic metals such as gold, copper, silver, aluminium etc. or a user defined specular reflectivity spectrum. The nkdata profiles are contained in the nkdata folder that comes with Indigo. Indigo doesn’t support transparent nk materials. Not all the supplied profiles will work. For a summary of the ones that do and previews go here external link to DeepPixel projects The only parameter to set for nkdata is the Exponent value - all the others are taken care of by the .nk data in the file.

To set a material as Phong, first select the mesh in the 3d window and then select “Phong” from the materials drop-down menu. You can control the Phong colour (basic colour) with the colour mixer (just as for the Diffuse material); the Exponent and IOR parameters are entered in the labelled fields.

Phong examples showing increasing shininess - exponent of 300, 3000, 100,000:

phong1.jpg phong2.jpg phong3.jpg

example of phong XML:

<phong>

 <diffuse_albedo_spectrum>
   <rgb>
     <rgb>0.5 0.5 0.9</rgb>
     <gamma>2.2</gamma>
   </rgb>
 </diffuse_albedo_spectrum>
 <exponent>300</exponent>
 <ior>1.5</ior>

</phong>


NKdata examples - gold, copper and chrome: and Specular reflectivity example:

Gold (Au.nk)

Copper (Cu.nk)

Chrome (Cr.nk)

spectral reflectivity

5. Specular

Specular is a material that can be both a perfect specular reflector and a perfect specular transmitter. This material can be used for transparent or mirror objects like glass, diamond, transparent plastics, water, and also for the sub-surface scattering feature (SSS). To set a material as Specular, first select the object in the 3d window and then select “Specular” from the materials drop-down menu.

Specular type:

1. Glossy transparent:

2. Specular: specular1.jpg

example of specular XML:

<specular>

 <transparent>true</transparent>
 <ior>1.5</ior>
 <cauchy_b_coeff>0.0</cauchy_b_coeff>       
 <rgb_absorptivity>0 0.1 0.2</rgb_absorptivity>

</specular>


Medium type:

1. Basic:

2. Skin:

skin Human skin is a highly scattering material. Indigo models skin in 2 layers, the dermis and the epidermis. To use skin you will need to offset your torso mesh with another by a small amount to use for each layer and give them precedence.

Dermis (inner skin layer): the hemoglobin fraction Ch

Epidermis (outer skin layer): the melanin fraction Cm and the eulmelanim/pheomelanin blend Bm Typical values are: Caucasian- Ch=0.005 Cm=0.005 Bm=0.7 Asian- Ch=0.01 Cm=0.15 Bm=0.0 African- Ch=0.05 Cm=0.50 Bm=0.7

3. Atmosphere: extra-atmosphere

Identifies the material to be used as a special with the extra-Atmosphere environment option. “extra atmospheric” means outside of the atmosphere. When it’s turned on, attenuation and scattering in the atmosphere is turned off; the incident sun radiation is equivalent to that at the outer edge of the Earth’s atmosphere. There is a Turbidity setting. To render an atmosphere requires 3 spheres representing the Earth and inner and outer atmosphere with appropriate dimensions (use worldscale factor). Extra-atmosphere is slow to render. This system can also render things inside the atmosphere if you turn of the extra Atmosphere.

Precedence

Precedence is used to determine which medium is considered to occupy a volume when two or more media occupy the volume. The medium with the highest precedence value is considered to occupy the medium, ‘displacing’ the other media. The predefined and default scene medium, ‘air’, has precedence 1.

Cauchy B coefficient

diamond- IOR 2.37447, Cauchy B 0.01348 Cauchy’s equation is an empirical relationship between the refractive index n and wavelength of light λ for a particular transparent material. It is not especially accurate into the infrared but fine for the visble spectrum. Typical values for the B coeff lie in the range 0.004 – 0.013. Dispersion is most commonly associated with the rainbow colours arising from a prism. Using dispersion makes for a very slow render. Setting the coeff. to 0 disables it.

Absorption

Sets the colour and gain for the absorption or technically it controls the rate at which light is absorbed as it passes through the medium.

Subsurface scattering

Sets the colour and gain for the scattering or technically it controls the rate at which light is scattered as it passes through the medium.

Scatter type:

- RGB

- Uniform

Phase function: The phase function controls in what direction light is scattered, when a scattering event occurs.

- Uniform

- Henyey-Greenstein

The Henyey-Greenstein phase function is useful for modelling assymetric (non-uniform) scattering, particularly forwards scattering. The g parameter is called the assymetry parameter and determines the amount of forwards or back scattering. g = 0.95 ~ mainly forwards, g = 0-.95 ~ mainly back. In fact g is the average cosine of the scattered direction with the incident direction. Each of the RGB channels can have a ‘g’ value.

6. Blended

leaf-phong_transmiter.jpg Indigo allows you to blend 2 materials together. You can even blend blends together. There is a proviso with blends though in that you cannot blend 2 specular materials (or actually emitters since they arent really materials as such). The null material listed in the dropdown menu is a very simple material that doesn’t scatter light at all. It’s effectively invisible. The null material has no parameters. The degree of blending between the 2 materials is set by the blend factor slider. Alternatively the blending can be mapped per pixel by an RGB image.

To the right is an example of a blended material used for a leaf. Click on it to see an enlargement. The combined characteristics of each type of material make for a much more realistic effect.

7. Exit portal

exit_portal.jpg In some situations - most notably for architectural subjects - Indigo renders quite slowly. The sunlight is for instance coming through small windows or skylights and there is quite a lot of indirect light in the room. In this situation Indigo can improve performance if you use exit portals. Exit portals are just meshes covering the openings (with their normals facing inward) and identified as portals in the material options. You should use Bidirectional tracing, and choose your Environment setting as usual. For windows you needn’t bother with glass just make the portal mesh. The portal mesh needs to seal all openings. In the case where you might want windows because you want to render stained glass for example you need to make sure that the portal mesh is offset from the glass by at least the ‘nudge distance’ (see the later description).

Only sunlight will work with portals. Any mesh emitters must be inside the room.

8. External

Not a material as such but a way to reference a material as an included file.

9. Tabulated spectrum * not in menu

tabulated_water.jpg Indigo has the ability to utilise material characteristics defined by a numeric table. Most likely you would consider this method for very accurate depiction of water, glass or gems derived from scientifically measured data however any material that expects a spectrum element can use a regular tabulated spectrum input.

  • Presently to use a material with a tabulated spectrum you would use it as an included file. Blendigo does not have any built in method to generate or handle tabulated spectrum data other than refer to the file at export for Indigo to access.

Here is an example compiled by forum member CoolColJ for pure water including subsurface scattering data:

Indigo XML:

   <medium> 
       <name>PureWater</name> 
       <precedence>10</precedence> 
       <basic> 
           <ior>1.33</ior> 
           <cauchy_b_coeff>0.00000</cauchy_b_coeff> 
           <absorption_coefficient_spectrum>      
           <regular_tabulated> 
              <start_wavelength>0.34E-06</start_wavelength> 
              <end_wavelength>0.75E-06</end_wavelength> 
              <num_values>83</num_values> 
              <values> 
              0.0325 0.0264 0.0204 0.018 0.0156 0.0135 0.0114 0.0107 0.0100 
              0.0094 0.0088 0.0079 0.0070 0.0060 0.0056 0.0052 0.0054 0.0061 
              0.0064 0.0069 0.0083 0.0095 0.0110 0.0120 0.0122 0.0125 0.0143 
              0.0130 0.0157 0.0168 0.0185 0.0213 0.0242 0.0300 0.0382 0.0462 
              0.0474 0.0485 0.0505 0.0527 0.0551 0.0594 0.0654 0.0690 0.0715 
              0.0743 0.0804 0.0890 0.1016 0.1235 0.1487 0.1818 0.2417 0.2795 
              0.2876 0.2916 0.3047 0.3135 0.3184 0.3309 0.3382 0.3513 0.3594 
              0.3852 0.4212 0.4311 0.4346 0.4390 0.4524 0.4690 0.4929 0.5305 
              0.6229 0.7522 0.8655 1.0492 1.2690 1.5253 1.9624 2.5304 2.7680 
              2.8338 2.8484 
              </values> 
           </regular_tabulated> 
           </absorption_coefficient_spectrum> 
                             
           <subsurface_scattering> 
                 <scattering_coefficient_spectrum> 
           <regular_tabulated> 
              <start_wavelength>0.34E-06</start_wavelength> 
              <end_wavelength>0.75E-06</end_wavelength> 
              <num_values>83</num_values> 
              <values> 
              0.0104 0.0098 0.0092 0.0097 0.0082 0.0077 0.0073 0.0069 0.0065 
              0.0062 0.0059 0.0056 0.0053 0.0050 0.0048 0.0045 0.0043 0.0041 
              0.0039 0.0037 0.0036 0.0034 0.0033 0.0031 0.0030 0.0028 0.0026 
              0.0027 0.0025 0.0024 0.0023 0.0022 0.0021 0.0020 0.0019 0.0018 
              0.0018 0.0017 0.0017 0.0016 0.0015 0.0015 0.0014 0.0014 0.0013 
              0.0013 0.0012 0.0012 0.0011 0.0011 0.0011 0.0010 0.0010 0.0010 
              0.0009 0.0009 0.0009 0.0008 0.0008 0.0008 0.0008 0.0007 0.0007 
              0.0007 0.0007 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0005 
              0.0005 0.0005 0.0005 0.0005 0.0005 0.0004 0.0005 0.0004 0.0004 
              0.0004 0.0004 
               </values> 
           </regular_tabulated> 
              </scattering_coefficient_spectrum> 
              <phase_function> 
                 <uniform/> 
              </phase_function> 
           </subsurface_scattering> 
       </basic> 
   </medium>

   <material> 
       <name>Water</name> 
       <specular> 
           <internal_medium_name>PureWater</internal_medium_name> 
           <transparent>true</transparent> 
       </specular>
   </material>


If you want to know more about setting up tabulated data try a forum search to find discussions about it.

10. Indigo material files (.igm and .pigm)* not in menu

Presently Blendigo does not support the export or import of Indigo material files or their packing and unpacking. You can hand edit the code if you need to be like this for an .igm:

<?xml version="1.0" ?> <scenedata>

  <material> 
  ...the material code goes here... 
  </material> 

</scenedata>


Material libraries

At present neither Indigo nor Blendigo come with any supplied material sets. Exporters for other applications have incorporated some presets accessible from the UI but this has not been done with Blendigo yet.

Some forum members have started their own databases allowing Indigo users to up and download materials to share. Unfortunately they have only a few entries presently.

   *
     The Indigo Materials and Textures Database by Dougal2 (using the .igm format)forum link here
   *
     My Material DB site by joegiampaoli external link

Larger material resources can be found at:-

   *
     Schott Glass Material Library by WytRaven (using the tabulated spectrum format) forum link here
   *
     the Indigo forum thread: ‘Material Thread - Post your materials here?’ forum link here

FAQ for materials

  1.
     How can I make fog? To create fog in your scene make a large closed volume (mesh) around the whole scene with the normals facing out and apply a transparent specular material with subsurface scattering to it. Set IOR = 1.0 or 1.001, absorption to 0 and a Uniform scattering coefficient to something like 0.01-0.05 (the greater if you want a thicker fog). Make sure that your fog mesh has a precedence of 2 and every other material with precedence has a higher value. The fog geometry can be any shape you want. Try a cloudish shape rather than just a cube. If you want to go to extremes you can also use multiple layers of fog with different densities i.e. scattering. There is a short wiki tutorial available demonstrating a related situation - sunrays in dusty air. tutorial link here
  1.
     How can I make flames and smoke?
  2.
     How can I make clouds?
  3.
     How can I make grass? Take a look at DrBouvierLeduc’s grass tutorial. forum link here
  4.
     How can I add 2d people and trees to my render?
  5.
     What settings give the best caustics? Make sure your light source is very small, otherwise the caustics will become so blurry as to be invisible. The smaller the light source, the sharper the caustics. The sun is fine too. Make the Max Depth = 10,000. Note that caustics take a while to appear in the render particularly with the sun as the light source so dont end it too soon.
  6.
     How can I use Blenders displacement? -for such things as water ripples, brickwalls and pebble gardens-
  7.
     Can I use Blenders precedural textures? Yes you can bake them to a UV map. forum link here

Note that ‘Unwrap (smart projections)’ in Blender 2.45 was previously known as ‘ArchiWrap UV Projection Unwrapper’.

Exporter module

Camera settings

The camera lens and hence angle of view is set in Blenders camera settings by the ‘Lens’ field. From a purist viewpoint this is not especially accurate for Indigo purposes. If you want you can adjust this to give camera/lens specific setting if you find a manufacturers real data to work from. For instance to model a Canon EOS 1DS the following could be used.

hasselblad.jpg Canon lens (mm). Blender setting. 28 26.5 35 32.15 50 44.25 85 72.40 100 85.55 135 112.75 200 165.15 300 245.85

fisheye.jpg Note 1: Indigo cannot do orthographic renders.

Note 2: People have experimented with modelling lenses for Indigo from time to time. Search the forums for examples. To the right is an image from a fisheye experiment.

Film ISO and 'film' width

Photographers set the speed of their film in the ISO scale and use a format that might be the familiar 35mm or perhaps the larger 65mm. In Indigo you can set the system’s exposure gain using a similar scale and nominate the width of the electronic light sensor. The default value is 36mm. Digital cameras have sensors of about 4-8mm for ‘Point and shoot’ 4MP - on up to 36 mm 16MP for ‘professional’ use.

Shutter

You can set the duration of exposure using the shutter setting. This has a scale anyone familiar with a camera would recognise, each step being half the duration of the last.

F-stop

dof_prisms.jpg The aperture change is modelled to be between f1.2 and f64. This mimics a real cameras depth of field control. f1.2 will produce an image with a very blurred foreground and background and f64 a sharp picture throughout. Somewhere about f8 if a good compromise between being focused and depicting a degree of realistic blur. It is very important to set up your scene to be dimensionally true or the DOF will either not show any effect or will be excessive.Remember 1 Blender unit is equivalent to 1 metre in Indigo - you need to get everything in the correct scale.

White balance

d50.jpg d75.jpg The white balance setting is a way to match the camera characteristics to the the type of illumination so that there is perceived to be a true white. This is akin to the way your eyes adapt to the conditions of a dim room or candle light. There are number of possible values to choose based on a ‘blackbody’ emitter at various temperatures. If you set the white balance to D50 and render the room with a 5000K emitter, the light should appear white. If you set the white balance to D75 the same scene will come out kind of orange.

Exposure Adjust

Just as for a digital camera Indigo has provision to adjust the exposure in smaller steps than half or double typical of the changes to the shutter or f-stop. In most cases it is in 1/3 step increments with +- 2 full steps being available. This is very handy for fine tuning the overall render exposure or maintaining a certain DOF in preference to some other parameter or making exposure sets. To some extent you can alter your saved .png image after the fact either in Blender or another program like Photoshop but it is nice to get it fairly correct to begin with.This will probably entail doing some test renders of your settings to make sure all is well. If you save your image as an .igi or .exr you have more scope to change the result afterward because a fuller amount of colour information is preserved.

Auto exposure

With this option Indigo will take care of the correct exposure of your scene for you.

Focus and selection

There are 4 ways to determine the in focus point for the camera in a scene.

  1.
     set a distance from the camera numerically.
  2.
     enabling auto-focus in Indigo - actually the closest mesh point to the camera.(the closest autofocus distance allowed in Indigo is 0.1mm).
  3.
     at the selected object in the 3d window.
  4.
     at the 3d cursor.

If you change the Worldscale later dont forget to reselect the focus point setting to update the distance to the correct scale.

Glare (Aperture diffraction)

obstacle.jpg Prior to Indigo 1.0.3 the method for calculating glare was pretty slow to compute so you may have preferred to achieve it in ‘post-production’ with the Violet Tone Mapper rather than render it in Indigo.That is still an option but from Indigo 1.0.3 onward the glare method was revised and includes the possibility of using an obstacle map as well of either 512,1024 or 2048 px square to produce various diffraction effects. The results in Indigo are somewhat better than Violet.

Aperture shape

aperture.jpg Indigo has 3 options for specifying the aperture shape used:

  1.
     circular, the default.
  2.
     generated, by specifying the number of blades, offset, radius, and starting angle.
  3.
     image, a .png image either 512,1024 or 2048 px square.

Unless you use the circular aperture the overall exposure will be somewhat masked by the aperture shape. This means that you will need to compensate a bit for the loss by applying some Exposure Adjust.

Image size

You can set the image size in pixels directly or the script will read the values set in Blender. In the last script menu of the size entries you can elect to render as a percentage of the full size. This is useful because you can do a quick thumbnail of the full render to check everything is as you anticipated it. Indigo will run out of memory doing the calculations for very large images so you would be advised to keep render sizes less than 1600×1200 to begin with. 2400×1800 is pushing the limits with 3gb.

Region rendering

regions.jpg This allows you to just render a small portion of your camera view and is usually done for test purposes. It is only available for Linear and Camera Tonemapping options. You can select and view the intended region using Blenders ‘Border’ tool in the camera view. The rendered image will be the full size except that only the identified region will be actually rendered.The rest will appear black in the UI window but is blank/alpha in the saved image.

*Reminder*

These exposure control elements are inter-related and there are a number of combinations of ISO speed, aperture, shutter speed settings etc. that give an image that is ‘correct’ just as in real photography.

Environment settings

None (lit by emitters)

In this case the scene is illuminated by emitting meshes. The parameters for the emission are set by nominating the mesh(es)as an emitter material. Obvious examples are a neon sign or a glowing light bulb filament.

Environment map

room_latlong.jpg kitchen_spherical.jpg Indigo can use a HDRI map as a source of illumination for a scene or in combination with other light sources. It uses .exr format but of course Blender can view both .exr and .hdr in the UV/Image Editor, and with the curve tool adjust them and then save as the other format, so it is possible to utilise a large number of maps available on the internet.

Indigo can use .exr in either lat-long or spherical format.If you specify spherical you must also specify the dimension of the side/diameter.

In the case of environment map illumination (including EXR lat/long maps), the pixel values in the map are interpreted directly as spectral radiance values.This gives pretty low values usually. If you are trying to balance .exr illumunation with emitters -including IES profiles- you could probably set an .exr gain of about 500,000 as a ballpark figure. Gain only affects the illumination in the cases of Camera and Linear tonemapping.

Presently there is no way to rotate an .exr map in Indigo. As a workaround rotate your camera and objects in the scene.

Physical sky and sun

skylight1.jpg Probably the most common type of environment is that of the physical sky and sun. Indigo models the clear sky and sun position and has a setting for turbidity varying from 2 for most clear through to 5 for hazy. These are based on actual atmospheric readings. Typically this could be set at 2.2 - 2.5

You need to set up a Sun type lamp in a Blender scene to use this illumination. The direction of the sun and hence the cast of the shadows is indicated by the dashed line. This is the only Blender lamp type supported in Indigo.

Background colour

bgbike.jpg

When this option is chosen for the environment Indigo will use the selected background colour to illuminate the whole scene. It casts an even tinted light. In Blendigo the default background colour is black. If you have set ‘Background colour’ by accident rather than say ‘Physical Sky and sun’ for your render this might be the reason why you are getting a fine image of a starless night.

Worldscale

If you import various file formats and sizes of meshes into Blender you can of course scale any mesh to suit you preference. However Indigo is a physically accurate renderer and as such the dimensions of the objects matter. Bear in mind that 1 blender unit corresponds to 1 metre in Indigo. This is especially important for such things as accurate depth of field and correct subsurface scattering. A useful tool to have available is the Worldscale setting. This works as you might expect in that setting it to 0.1 will result in the whole scene being scaled on export to 1/10 th size.

Ground plane

This enables an infinite ground plane within Indigo centred at 0,0,0, This is not suitable when used with Bidirectional tracing however because it causes artifacts.

NOTE: The Ground Plane option has been deprecated and is no longer supported on recent Blendigo releases. Modeling of a true mesh plane is advised now.

Renderer settings

LM probability

Max change

Max num consecutive rejections

Max depth

Max depth is the maximum number of bounces a ray can take around the scene in the render process. When Blendigo is first run the default value is 1000 but a larger 10,000 is probably better especially for caustics.

Supersamples

This is like anti aliasing for Indigo. It helps with high contrast edges. The downside is that it consumes more memory to use it. If you have a small amount of RAM set this at 1, if you can afford it run it up to 3, 2 is fine for most purposes.

Downsize filter

You have the option of selecting either a Mitchell Netravali cubic or a box filter when the image is saved. The filters are only available when supersample is set > 1. The cubic filter has Ring (’C’) and Blur (’B’) parameters exposed - the defaults are 0.2 and 0.6 respectively where 2*C+B=1 Some people find the default settings make for a rendered image that is too blurry or soft in appearance in which case you could try 0.333 and 0.333 for your values. The box filter is sharp but may cause aliasing in some cases whereas the cubic filter has good anti-aliasing.

Ray Nudge

This is a factor you rarely if ever adjust. Nudge distance is important though when it comes to rendering, for example, wine glasses and their contents because the glass will need to be elevated from the floor by about 2x the nudge distance and the wine overlapping the glass to render correctly. The nudge distance is automatically scaled by the script as the Worldscale setting in increased to ensure there are no artifacts generated from disproportionate scenes.

Pathtracer

With no type of render method selected i.e. not MTL or Bidirectional, Indigo uses Path tracing. This is for scenes with direct light. Path tracing needs longer to render scenes with indirect light, and glass or caustics. The noise is uniform.

Metropolis

Metropolis light transport -or MLT for short. This is suited to scenes with indirect lighting and glass or caustics. MLT is not so good for direct light situations. Generally the noise is kind of dirty-patchy-nonuniform.

Bidirectional

This is also suited to scenes with indirect lighting and glass or caustics. Using Bidirectional makes the noise clear faster.

Hybrid

Hybrid is a combination of MLT and PT. Hybrid uses PT for direct light and MLT for indirect light. This is good choice for glass and caustics. Hybrid combines the strengths of MLT and PT. If Hybrid is enabled the Metropolis setting is ignored by the exporter. When you use Hybrid the image will have a noticeably different noise pattern during rendering but converge to exactly the same image as other types. All of the render methods will ultimately converge to the same result. The setting called ‘_hybrid threshold’ has a default of 500,000. If the model has more triangulated faces than that, it will use a BIH instead of a kd-tree. If you just want to use strictly BIH, set it to 0.

Combinations of MLT, Bidirectional and Hybrid

Each type of render calculation has attributes that make it suitable for certain situations and likewise combinations of them. Some modes are faster, some slower for different purposes/scenes. Because it is a physically correct renderer each method would in effect refine to give the same image given sufficient time.

Possible Combinations:

- Pathtracing Mode: (”Metropolis”-false)

- MLT Mode: (”Metropolis”-true)

- Hybrid Mode: (”Hybrid”-true)

- Bidir MLT Mode: (”Metropolis”-true, “Bidir”-true)

- Bidir Pathtracing: (”Metropolis”-false, “Bidir”-true)

- Bidir Hybrid Mode: (”Hybrid”-true, “Bidir”-true)

The last two modes are recommended.

Tonemap settings

Camera

When this option is used Indigo can make use of measured camera response data to mimic the appearance of a colour film such as Agfacolour OptimaII-200 or Kodachrome 64. Indigo includes only one such data file with the install but you can find a collection of additional files posted to the forum.

To use this feature you need to select the Camera option from the Tonemapping type menu and navigate to the ‘camera_response_functions’ folder containing .txt files with the film specific data and then select one. The folder is located inside Indigo’s data folder. Remember to set the appropriate ISO rating for the film in the Blendigo Camera settings afterward. The shutter, f-stop, white balance and exposure adjustment will all play a part in obtaining the a correctly exposed image as per a real camera.

Reinhard

pre1-post1-burn10 pre1-post3-burn10 pre1-post5-burn10

pre3-post1-burn10 pre3-post3-burn10 pre3-post5-burn10

pre5-post1-burn10 pre5-post3-burn10 pre5-post5-burn10

This series of renders shows the effects of adjusting the Burn, Prescale and Postscale settings. See the rollover labels for the settings of each render.

Burn: Burn to white. 0.1= a lot, 100= none. typically 10. Burn can be thought of as bringing up the exposure of local dark areas to avoid the loss of detail. If a scene has a wider dynamic range than can be printed some areas that have visible detail will be mapped out of range to pure black or white. Sometimes such loss of detail is desirable, such as a very bright object being mapped to pure white. Sometimes we want to recover say being able to see text on a page of a book by dodging (opposite effect of burn).

Prescale: Setting the mid-grey point. This is similar to a photographer using an 18% grey card in the scene for substitute metering to get an exposure where all tones will be reproduced in the print. i.e. detail is not lost in areas when the whole exposure is shifted tonally to be too dark or too bright. When a film is ISO rated the 18% grey equates to the mid point in the dynamic range. In Indigo the pixel buffer is scaled by this factor before the non-linear stage of the tonemapping takes place. 2 is typical.

//Postscale:// The white point. This scaling factor is applied after the rest of the tone mapping stages. By default, the pixel in an image with the max luminance is mapped to white, so setting this to > 1 will result in pixels with less luminance being mapped to white. 1 is the default.

Linear

System settings

Gamma

This is an old option and somewhat redundant. You can specify the overall gamma for Indigo here. Really there is no reason to use anything other than 2.2 for this.

Threads and auto

If your computer has multiple processors or thread capability you can specify the number you wish Indigo to use. If the auto thread option (not on screen shot) is chosen Indigo will detect the number available - i.e. 4 in a quad.

Frame Upload

When you render with computers networked together to share the task, Indigo will have a master and slaves operating. This setting controls the frame upload time to the master.

Halt at time

You can set Indigo to automatically stop after a period of time. This setting is in minutes. If you set the figure to -1 Indigo will run on until you actually terminate it yourself by closing the UI window.

Halt at samples

You can set the render to finish at a predetermined number of samples / pixel. This has advantages if you want to run until a certain clarity of image is produced - for instance you might be happy if an image renders to 1500, rather than estimate the time taken, which might be affected by other processor activity. This setting is also useful when rendering animations because each frame will be completed to approximately the same standard. A setting of -1 disables this option.

Display period

Indigo will update the render progress in the UI at intervals specified by this setting. While it is handy to follow progress it is also time consuming to update the display, so it is better to set this for a reasonable time, perhaps 1 minute or more, if the render will be of a long duration.

Save period

Indigo will save the rendered image at intervals taken from this setting. Again, as per the display period, this takes time that might be otherwise used for rendering calculations so its best to use it sparingly.

Cache to disk

This enables caching the trees to disk rather than rebuilding them each time.

Use console vs. UI

console.jpg ui.jpg In later script versions you can choose to use either the Indigo UI or the older console arrangement. While the UI is nice the console runs a bit faster within less resources and may be preferred. The console does not display the rendered image in progress.

Logging

Selecting this option enables the writing of a log.txt This will be written to the same folder as the Indigo.exe

Watermark

When enabled Indigo will overprint an ‘Indigo renderer’ watermark on the saved .png image. If you wish you could replace the official provided watermark.png with a custom one.

Save utm EXR

In addition to the saving of the image as a .png you can enable the saving of a untonemapped EXR This is useful if you wish to use the Violet Tone Mapper to adjust the exposure etc The .exr will preserve the full amount of colour information available.

Save tm EXR

In addition to the saving of the image as a .png you can enable the saving of a tonemapped EXR for much the same reason as the untonemapped version.

Save IGI

Indigo has the functionality to save its workings in progress so that it may be resumed on a later occasion. This is saved in an .igi file at the same time as it saves the render as a .png Unfortunately the .igi can be a very large file and as such takes a while to process. The advantage is, of course, you can run your render over several sessions at a time that suits you rather than have it slog away through the night....

Save as alpha

dof_prisms.jpg This will save the image as having an alpha foreground for compositing purposes. Not available with bidirectional rendering.

Splat Filter

Indigo has a choice of a Gaussian or a Mitchell Netravali cubic splat filter, that is, the filter used for splatting samples onto the image buffer. Gaussian is sharp but has some aliasing while the cubic filter has good anti-aliasing but can have noticeable ringing which some people may not like. The cubic filter therefore has Ring (’C’) and Blur (’B’) parameters exposed - the defaults are 0.2 and 0.6 respectively where 2*C+B=1 It is not quite as sharp as Gaussian but is recommended. Some people find the default settings make for a rendered image that is too blurry or soft in appearance in which case you could try 0.333 and 0.333 for your values.

Export options

When you export your scene from Blender via Blendigo you automatically save all of the geometry, materials and settings as an .igs file. This file comprises XML statements Indigo understands. The .igs file can be opened in Notepad for viewing on manual editing. The file will reference paths to your textures, .exr maps and other data like IES profiles.

Autorun

When this is enabled the script will launch Indigo rendering your scene after it has finished exporting it as an .igs file. There will be a small delay while the scene is processed and then the Indigo UI or console (depending which you specified) will appear showing the data loading in Indigo.

Separate meshes and materials

Rather than export all of the data for Indigo in one file it is possible to split it up. This has advantages if manual editing is desired later where the files are quite large and you don’t really want to be opening them in Notepad. Blendigo gives you the option of writing the whole to a single .igs or separating the materials or the meshes from the main file as included .igs. The handling of these tasks is taken care of by the script.

Includes

Includes are a spin off from the separating of meshes and materials. Sometimes it is more practical to break down a large scene into small chunks. Typically it is easiest to deal with meshes in Blenders layers for this. This function is most useful as a means to get around memory limitations of both Indigo and Blender. Indigo is quite happy to load a chain of lesser include files that detail the whole scene whereas it would not take a single large file. The same is true for Blender when exporting.

Animation

Indigo can be used to produce animations although not too many have been made because of the time required to render even modest movies. To make even a minute at 24 fps will probably tie up your computer for weeks. Still the possibility exists. Most likely the console version of Indigo is the best option to use. As per stills the standard output is .png with the usual options of .exr and .igi.

Stills

The images rendered in Indigo are saved in .png format which is a ‘lossless’ format. Indigo does not generate alpha except in the case of saving the foreground as alpha (see above). In most cases .png is quite acceptable however Indigo works with more precision than that and you can save your images as .exr as well which maintains a fuller dynamic range of colour. The performance of Indigo is fairly proportional to image size so if you double the dimensions of the image to be rendered you can expect it to take 4x as long to achieve the same degree of clarity noise wise.

Scene packing

To make render files easy to handle Indigo has the facility to pack all of the referenced .igs, .exr, textures etc into one zipped file (.pigs) and also soon to unpack these and render them. This feature is accessed from the Indigo UI header or by command line. Blendigo doesnt yet offer the ability to initiate this natively.

Network rendering

Indigo supports distributed rendering over a TCP/IP network. Setting this up is as simple as enabling a computer as a working master and then enabling another computer(s) as a slave(s). The slave will then scan the LAN and finding the master, download the scene file name, load the scene, then join in the rendering. If the master is killed, then the slave will go back to scanning the network for new masters.

Windows

To set this up you need to start Indigo from a Windows command line:

start menu -> run -> cmd


Next change to the drive and directory where Indigo lives on your computer. For example if Indigo is installed to c:\indigo\indigo107\ type the following - (hit enter after each line)

c: cd \indigo\indigo107


Next run Indigo as a working master:

indigo.exe -n wm c:\scenes\TheSceneYouWantToRender.igs


and Indigo will start rendering the scene...

on your other network machines which are to be slaves start Indigo similarly but with the following:

indigo.exe -n s


Note: Make sure that both the master and slaves have access to the .igs and it’s textures etc VIA THE SAME DRIVE AND PATH i.e. a shared folder, otherwise the slave will fail to load the scene.

You can also refer to the Indigo Manual.pdf that comes with the Indigo download for network rendering details.

Linux

See these forum threads:

network rendering on linux mixing linux/windows render slaves

FAQ for networking

   *
     I’m having firewall issues on the server. What ports are necessary for -n wm auto discovery?

The default main rendering port is TCP 7777. The discovery service needs to listen on UDP port 7776, and the clients need to listen on UDP ports 7100-7110.

   *
     What happens if I want to render two scenes on the network simultaneously?

Start the two masters on different ports, like this:

indigo_console.exe -n m -p 7500 indigo_console.exe -n m -p 7501

Then you can start slaves while specifying the master hostname to connect to:

indigo_console -n s -h localhost:7500 indigo_console -n s -h localhost:7501

A working master will accept an alternate port.

   *
     Is it possible to disable the scanning?

The scanning is only enabled when an explicit hostname (-h) is not supplied.

Utility programs

Indigo Resumer

resumer.jpg The Indigo Resumer is a small utility by Daniel Nieto to enable the easy restarting of a render session saved with an .igi file (see System options) through an interface rather than command lines. The .igi file contains the render data up to the point where the previous render was terminated. Presently there is no way to suspend a render in progress via the Indigo UI. To use the resumer you need both the original .igs and the progressed .igi file.

IndigoResumer 2.3 is available from the ‘Indigo Renderer General Stuff’ forum.

Violet Tone Mapper

violet.jpg The Violet Tone Mapper is a utility to enable the post processing of a render saved as an .igi file. The .igi file maintains full detail of the image. Capability includes the zoomed display of the image and adjustment of white balance and Reinhard and Linear tone mapping, noise reduction filters, and glare, bloom and chromatic aberration generation. You can ‘save as’ an .png or .jpg image when you are happy with your adjustments.

Violet 0.3 is available from the Download menu. A java based version is in development.

NK converter

nk_modifier.jpg A utility by tinman999 to customise nk data files.

The converter is available here external link to download

Carmine Substance Editor v1.00

carmine.jpg A utility by Wedge to create materials to save for including or for cut and paste substitution in existing .igs.

Carmine is available from the Indigo Renderer General Stuff forum. This program may require .NET Framework 2.0

IESgen3

ies_gen3.jpg A utility to view and modify IES profiles.

IESgen3 is available here: external link to download Заголовок ссылки

Личные инструменты