Rendering your Blender scenes using Indigo If you've never heard of Indigo before, or seen what it can achieve when it's used as a companion to Blender, then go visit
http://www.indigorenderer.com and prepare to be amazed!
Indigo is a truly awesome tool and one of the best things is that it is FREE for non-commercial use ***(see footnote update on V2.0)*** . Here's what my effort turned out looking like after it finished rendering......
Notice the natural and photo-realistic way the lighting and shadows are all cast. Indigo achieves this by calculating the path of lightwaves indirectly as opposed to directly (which you'll get if you render your images using Blender's internal raytracing renderer). I thought I would share my experiences with using the Indigo renderer with other Blender Underground users in case anyone finds it useful. I had some difficulty finding any really good tutorials on scene set-up and scaling which are important considerations when using Indigo.
Strictly speaking, I'm not making a comprehensive tutorial here. I am simply posting some tips which newbies can use as a starting point to helping them on their way to creating great-looking renders.
So what is Indigo?Indigo is known as an 'unbiased rendering' program. The term 'unbiased rendering' in 3D modelling refers to a method of rendering an image where GI (Global Illumination) is calculated in order to produce more realistic results. These render processes employ advanced algorithms that take into account both direct light from a light source (direct illumination), and the light rays which are reflected by other surfaces in the scene (indirect illumination).
Indigo is a fully-capable, standalone rendering program complete with its own GUI. It is not a 3D modelling program. It is an external rendering tool which can be used with many 3D programs such as 3D Studio Max, Maya and Cinema 4D and Blender. You can think of it as a kind of plug-in renderer. Indigo is leveraged within Blender by way of a script-based exporter. This script, which is written in Python, dumps your entire scene data and material settings to an XML file which is then passed to the Indigo program.
One of the great things I love about this is that once your scene is handed off to Indigo for rendering, you can continue working away in Blender, and that's something you can't do if you render internally.
Of course the principal disadvantage to using an unbiased rendering program like Indigo is that your renders will take longer..... a lot longer. This is because there are many many more complex calculations needed in order to measure the way light behaves realistically. This means that you may need to wait for two or three render passes before you have just enough visual information in order to know if you've set up your materials or lighting properly. Unless you have access to a really high-end workstation boasting dual or quad processors then this exercise quickly becomes a fiddly process. Indigo is best suited for high-quality stills images. Although you could feasibly use it for animating, my guess is that you'd need a warehouse full of high-spec machines with the budget of a Steven Spielberg movie to achieve it.
Download Indigo and Blendigo...Okay, if you're tempted to give Indigo a try-out, then the first step is to get hold of the program. Download the Indigo Render Core program from
http://www.indigorenderer.com. At the time of writing this, the current version is Indigo v1.0.9. It's available both for 32 and 64bit versions of Windows and also for Linux. I don't use the latter OS, so I'm afraid that I'm only going to deal with setting it up on Windows. You will also need to download the exporter script for Blender (known as Blendigo) which is available on the same site above. The Blendigo script exporter has its own GUI interface which you can call in the scripts window of Blender (more on this is a moment).
Installing...The Indigo program comes as a Zipped file. Extract its contents to a folder on your computer. This can be anywhere you like but I stuck it inside my Blender Foundation folder for simplicity.
Next, unzip and extract the Blendigo script files. There are several files and sub-folders contained in this and you need to place all of them inside your Blender Foundation program .scripts folder.
The file 'IndigoWrapper.conf' needs a bit of tweaking. Its purpose is to point Blender to the Indigo rendering core program which you just installed.
To edit IndigoWrapper.conf, change its file extension to IndigoWrapper.txt and then open it in Notepad or some other basic text editor. Edit the file path to point at the folder containing the file indigo.exe (the Indigo program). Mine looked a bit like this:
C:\Program Files (x86)\Blender Foundation\Indigo\. Save the file and change the file extension back to IndigoWrapper.conf. If it asks you to confirm the rename just go ahead and click Yes.
If it doesn't already exist, create a new folder called 'bpydata' inside your Blender Foundation .scripts folder. Put the file IndigoWrapper.conf inside this.
Install Python... Because Blendigo is scripted in Python, you'll need to check that you have the correct version of the Python framework installed. If you haven't already got this, then Python is also a free download available from the Python website at
http://www.python.org/. The version of Python you install needs to be the same version that your Blender application is currently compiled with. To check it, open up Blender, switch to console view and it'll tell you what version it is at the top.
Checking the installation...Now launch Blender and create a basic scene. If everything went well, then you should be able to export it to the Blendigo script. Choose FILE > EXPORT > BLENDIGO v1.0.9. You'll probably need to configure one of your Blender window panes to show the script window. My personal preference is to have the script window visible on the right hand side of my main 3D window and then my buttons window along the bottom but it's up to you and how you feel most comfortable working with it.
If the install didn't go right then you'll get script errors appearing at this stage. Check the manual on the Indigo website and also the support forums for more help.
Of course, we can't render our scene just yet because we haven't defined any materials yet. If we tried to do this now, we'll get error messages. My computer actually crashed when I tried to do this so always save your work before you render your scene!
Setting up materials...Now that everything is installed we have a bit of materials tweaking to do. Indigo requires that materials are assigned differently from the way you're probably most used to using in the Blender program. All you need to do is assign a new material in Blender and give it a meaningful name. You don't need to change any other properties like transparency, reflectivity or shader types. All of this is done using the Blendigo script GUI.
As long as you have given all of the materials in your scene a name, when you export your scene to Blendigo, you will be able to select them and assign new material types using the script GUI. Blendigo offers a concise range of material presets saving you the hassle of trying to emulate a specific material type accurately. These are based on real-world materials so you get realistic specular shaders for use with metallic or plastic objects and dull, matt materials for use with fabrics, stonework, walls etc. From here on just feel free to experiment. For a more info on Blendigo's preset material types, take a look at this web page:
http://www.indigorenderer.com/joomla/index.php?option=com_openwiki&Itemid=69&id=blendigoIndigo supports UV texture maps but at the moment not procedural textures or Normal maps. To use UV textures, set these up in your usual way using Blender's UV texture editor. I usually go ahead and define material settings in Blender as well as in Blendigo so that I can do quick render previews and check that all my textures are aligning properly. All you need to do before rendering in Blendigo, is tell it where to find your linked texture file. You'll find this under the Material settings button in the script GUI. It is somewhat inconspicuously marked 'Albedo'. There is a little button to the right of the Albedo input field where you can browse for your file. I could be wrong but it looks as though the only supported file formats are jpeg or PNG images.
Lighting your scene... Indigo supports only one type of Blender light type: the Sun lamp. Use it for exterior scenes in combination with the Physical Sky+Sun environment type which you can select from the Blendigo script GUI under the Environment setting button. If you are using the Blender sun lamp, be sure to rotate it so that its angle is pointing in the direction you want your sun to cast shadows.
All other lights (particularly for indoor scenes) need to be made as meshes and assigned the EMITTER = Lights + Meshes material setting.
Create a mesh object in Blender (I normally just use a plain UVsphere). Assign it a new material name and then from the Blendigo script GUI, assign it the EMITTER = Lights + Meshes material setting.
Since you are going to be working with mesh lights in your scene you need to tell Blendigo this. Click on the Environment button in the Blendigo GUI and choose 'None (lit my mesh emitters)' from the ENV Type drop-down box.
Here is a topographical drawing of my Blender scene which is a single room with two windows, various furnishings and three light sources. I have indicated the material values in case that helps you work out how I set things up. Keep in mind that your own modelling project might be completely different and require its own, individual lighting settings.
The main light source (the sun) is just a large UVsphere positioned on the outside of my room. The sun has been given a light type known as 'blackbody' which gives you access to light temperature settings in degrees Kelvin. The temperature of sunlight is around 6500K. Two secondary light sources form small table lamps visible in the left and right corners of the room. Once again, these are both small UVsphere meshes…sort of like a lightbulb. I've given both of these lights the RGB light type. The output in Watts is kept quite low (I've used about 40W) which I guess is about right for a standard domestic tungsten light bulb. You can alter the colour cast of the light source to anything you want in order to achieve more realism, but I've just kept mine white.
The scale of things... An important consideration with Indigo is that its real-world lighting measurements are based on a scene or model with a realistic scale. If you work to the principal of 1 (real-world) meter = 1 Blender Unit, then you can generally expect more probable results from your lighting settings. If you are working to any other scale, then there are settings in the Blendigo GUI to change the worldscale under Environment settings. You're on your own for that one!
The neverending render... I think I've touched briefly on the fact that Indigo takes longer to render scenes but one aspect you should be aware of is that Indigo never finishes rendering! Once you set it going, it'll just keep on going, there is no way to stop it except if you quit out of the Indigo program or pull the plug. Don't worry, because Indigo will save your image automatically every three or four passes (this is configurable by the way). It will go on gradually completing more render passes and slowly, your image will start to increase in definition and it will look less grainy. So it's kind of left to you to decide when your image is ready. My finished render (shown at the top of this post) took 44 hours to render before it looked crystal sharp and I decided to halt the render process. I'm using a 3 year old Dell workstation with an Intel Dual core processor. Had I used a more up-to-date machine with quad core, or maybe even dual quad core processors, I might have been waiting less time.
Other rendering options...It's worth mentioning here that you aren't necessarily tied to using Indigo. There are several other brilliant third-party render programs which you can also consider such as
VRay and
LuxRender. I'm currently trying out the latter as a comparison to Indigo.
Wrapping up...There we go. I've merely scratched the surface of what you can do with Indigo. A quick delve into their website will reveal even greater material and lighting presets although at the time of writing this, I have been unable to source any credible tutorials, so I guess a lot is up to your own personal experimentation. Feel free to share any of your experiences to this thread! I'll try and add new stuff if I can get time between projects.
Ciao.
***UPDATE: June 2009***Since writing this tutorial, Indigo has released version 2.0 of the Render program which is now a fully-commercial product. This means that it is no longer free to all. You can still download it and try it out though. I believe Indigo have made available 100 licenses at half price and these are being offered for a limited period on a first-come-first-serve basis, and these give you free upgrades to future releases, so get your orders in quick!
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