Simple: Where is the "Global Illumination" button?

Hello Everyone,

As I am learning Blender I have a friend who is guiding me through learning 3D modelling, but there’s a problem - he is a Lightwave designer. I sent him on of my pics, and he told the following:

> Lets continue to concentrate on the lighting in your scene. If you
> notice when looking at a photograph in the shadow areas there is light
> too even in when you are directly blocked by the sun. In 3D this effect
> of visible shadow detail is called global illumination which comes in
> several different forms. You can achieve this by using a global
> illumination plugin that should in your program, or using several other
> small lights to fill in the shadows. The trick with the light is to not
> have those lights cast shadows. So I don’t know how to turn off shadow
> casting but it is in the program somewhere. All 3D programs have them,
> but I’m not sure where it is in yours?

Does anyone know what he is talking about? And where I can find it in Blender?


Mr Head

Well, first off, Blender does not have true GI lighting. In order to get true GI, you need to render with either Yafray or Indigo.

What we do have is a fair equivalent, which is Ambient Occlusion, (AO). You can find that in the World Setting and there are many docs and tutes on how to use it online.


Or you can do this old trick with spotlights parented to an icosphere:

> Lets continue to concentrate on the lighting in your scene.
yeah so solve all your problems in one go by hitting the GI button.:smiley:

GI+IBL even better. Even less to think about.

I’d be happy with either or both for exterior architectural rendering with blender internal. But no go. Yafray does it as already mentioned but with the latest developments in the internal renderer with passes etc Yafray now seems limited otherwise.

Kerkythea is another renderer with GI, IBl etc etc. It’s free and there is a blender build with Kerkythea as a render option from the render panel or a Python script for exporting to Kerkythea. Don’t know how feature rich the exporters are.

Personally i’ve gone and bought Rendering and Lighting 2nd editon by jeremy Birn (Pixar Lighting Technical Director) so i can ‘concentrate on lighting’ but even in his book external lighting for photrealistic architectural renders is pretty much summed up by suggesting IBL and GI.

Good Luck

Well…Blender has radiosity which is the old partial solution for GI (finite element method). With ambient occlusion + radiosity and some playing around you can something that looks like GI and is completely internal.

And yes, there are loads of renderers that have GI that work with Blender - Indigo, Sunflow, Kerkythea and the tried an true Yafray so doing GI with Blender is easy. Indigo is actually easier than yafray in my opinion as so few settings are needed for good results - with it being unbiased and all.

As for shadow casting, you can switch shadows on and off for each lamp individually and at a material level (switching off “Traceable”) but currently there are no lightlists as such (to determine which lights will cast shadows for a given object) but that is coming soon (or so I hope!).