Addendum A

We will only focus on the adjustments that matter for the output quality of the gold material.

1) Hit F10 to open the �Render Scene� dialogue box

2) Click on the tab �Renderer�

3) Now you can see a long list of sections with tags such as �Brazil: General Options�, �Brazil: Render Pass Control�, �Brazil: Image Sampling� and so forth.

4) Click on the Tag �Brazil: Image Sampling� to expand that section. Most important for us aren the �Min Samples� and the �Max Samples� values.

These values define how many samples per pixel are calculated during rendering. If it is below 0 then only a fraction will be rendered which results in a very rough but faster output. The min value set the minimum of samples per pixels; the max value defines the maximum of computed samples, e.g. for hard contrasts or edges.

There are three presets already set in Brazil, and accessible via the Buttons �P1�, �P2� and �P3�. The worst image quality offers �P1� with the fastest rendering. The line �Min [-8 x -8] Max [1 x 1] tells that one rendering sample serves 8 pixels, utmost 1 pixel.

For a better looking preview hit �P2�. Beware that although it looks pretty nice the �Min Samples� value is below 1 and results, especially in animations, in flickering details.

�P3� offers with �Min [2 x 2] Max [4 x 4]� production quality which we want to achieve, but also takes very long to render.

Why more than one sample per pixel? I hear you asking. The answer is simple: Quality. The more samples you got for a pixel the closer you can estimate its color. Edges will be very pixelated and either one color, or the other. This is also called �aliasing�. The more samples per pixels you got, the better the renderer can choose in order to make edges smoother (=�Anti-aliasing� or �oversampling�). For a detailed description of anti-aliasing visit this Wikipedia site.

Of course, you can change the min/max values after selecting a preset to your needs. Especially when you�re rendering high quality stills, you might even boos the �P3� settings up to Min [4 x 4] Max [8 x 8].

5) Click �P3� and close the �Brazil: Image Sampling� section via clicking on its label again.

6) Scroll to the section labelled �Brazil: Luma Server� and expand it, yes, by clicking on its label.

In this section everything concerning lighting is controlled, from direct to indirect lighting, caustics, even global illumination (GI) and sub-surface scattering. Don�t worry, we are only interested in a very view settings.

7) Enable the indirect illumination by ticking the box �Enable� just under �Indirect Illumination�.

Indirect Illumination adds a great deal to a scene�s realism. It simulates the light not only emitted from direct scene lights but also the bounced light from other objects.

For example: A spotlight on a red wall in a room would result in the whole room being lit by the bounced soft red light from the wall. Without GI you would only see the spotlight on the wall, the other side of the room would be completely unlit. More on Global Illumination on this Wikipedia site.

Of course, indirect illumination slows up the whole rendering, but you can define just like with the Image Sampling Rate how you like to sample the GI.

8) In the group �Global Illumination� you can set the min/max sampling rates for the indirect illumination only. For a fast preview the values �min -4� and �max 0� are okay, but you can expect a little splotchy results, which look like a very compressed JPEG. For a better preview or even production I suggest staying below 0 saves you time, I suggest �min -2� and �max 0�. Everything above 0 is pure luxury but looks stunning.

There�s also a tickbox for locking the sampling rate to the image sampling rate, which is quite practical for previews.

Before rendering your final, you should test a lot the performance with a very small resolution. Don�t waste a lot of time rendering details, nobody will see.