03 June 2012

Blender 3D Architecture, Buildings and Scenery - Chapter 11 of 14 Review

This chapter covers the topics of Radiosity and Ambient Occlusion.

First item to be described is the general topic of what Global Illumination is and why you would use it.

How to use and setup radiosity is covered and emitters and the mesh collection process are covered for Radiosity use. The criticism I have here is that a lot of the settings of how to use Radiosity are described, but not very well and things such as what patches are and how their settings affect the overall Rodiosity of a scene aren't really explained. Another problem with the Radiosity example is there just aren't enough of them and topics such as how to cover things like tweeking scenes that have bad Radiosity results (such as light leaking behind other planes) just are not covered. Thankfully though some important options such as the direction of normals are covered so that is at least one potential pitfall that is described and avoided.

Another mistake I found was that it is said that when running the Radiosity calculations that it will continue forever until you tell it to stop. However with Blender 2.46 this is no longer the case. Also It says that Max Iterations being set to 0, are what cause this behaviour, however it appears to be the Convergence setting that does this when it is set to 0. One last final snafu is that when rendering radiosity results, it is not mentioned that the Add New Meshes/Replace Meshs buttons need to be pressed for a new mesh to be created with the Radiosity result embedded in them for it to be visible in a render.

Vertex painting is covered as a method to correct the results of Radiosity calculation.

Next Ambient Occlusion is covered as the other method of Global Illumination, giving a brief explanation of how it works. The options on the AO panel are explained but no examples of effects on each from changing the settings aren't demonstrated which is a shame. Though an outdoor example is given. The other problems is that Ambient Occlusion panel layout and some of the options have changed in Blender 2.46.

This was an ok chapter, but it was shame that a more detailed example of Ambient Occlusion and Radiosity settings was not given to cover the correction of bad light leaks.