Blender 3D: Noob to Pro/Faked Gi with Blender internal

Getting uniform studio lighting with the blender internal renderer



This tutorial will teach you how to use blender to create faked Global Illumination (here forth called "GI"). The reason it is faked is that blender currently doesn't support true Global Illumination but it's not a difficult task to fake. To fake global illumination, we will surround our subject with a lot of suns. The easiest way to do this is to create a very large sphere around our subject and place a sun at each vertex of this sphere, pointing inwards. Luckily, Blender can automatically duplicate an object at each vertex of another object. The results of this tutorial should look like this:


This tutorial assumes you know the basics of the blender interface and how to add objects, toggle editmode, and scale objects.

Now lets start blendering!

Blender Faked GI Tutorial

In more recent Blender versions DupliVerts and Rotation options can be found under the Object Data tab in the Properties Panel. Icosphere needs to be selected.

Add an ICO-sphere. Fire up blender and add an icosphere (SPACEaddmeshicosphere). Set the subdivisions to 3 and accept.

Scale the ICO-sphere by 15 times

Flip the normals of the icosphere so that they point inwards. This will make sure that our duplicated suns will point inwards. Go into edit-mode and press the A key till all faces/verts/edges are selected and press WKEY and Flip Normals.


Add a sun light source (SPACELightsSun)

Set the energy value of the light. This requires some special attention. If you keep the value at the default 1, you get a pure white, washed out scene because we will duplicate the light 162 times. A good way to calculate the light intensity required is to mess with the one sunlight and do test renders while tweaking the energy value of the sun as required till you get the brightness you want. THEN you divide the energy value of your sun by the amount of vertices in your icosphere and then finally set the sun energy to the number you got.

Noob Note: I found I had to set the energy of the sun lamp extremely low, at .044. Otherwise, you end up with a completely washed-out image.

Parent the sun to the sphere. Select the Sun THEN shift select the sphere and hit CTRL+PKEY

Enable dupliverts for the sphere. Depress the DupliVerts button. This will copy the sun to each vertex of the sphere. Also depress the ROT button. The ROT option tells Blender to rotate the suns to point along the normal of each vertex.


Enable AAO (Approximate Ambient Occlusion) This will result in more realistic soft shadows around our subject. Set the AAO settings in the world buttons as in the following image:


Set up the scene to render This can be anything you want but I used a simple curved plane with Suzanne on top of it.


One more note: Often it is hard to see your scene when you have this huge sphere encompassing your scene. So what you can do is to set the draw of the sphere to wireframe.


Just one last note: if you want more directional lighting, select the sphere and go into editmode and press CTRL+TAB+3KEY for face select and select one face on a spot of the sphere and press WKEY and subdivided a few times to get more lights in one spot making that side a bit brighter and a stronger shadow on the far side of that cluster.

Blend happy and save often.