[Thomas]

Part Four: Materials

Now we are going to apply materials, in order to get a more realistic - and much nicer - scene. Let's start with the floor. The easiest way here is to use a material from the Carrara Wizards. Let's take the "Stratified Wood" and drag-and-drop it directly on the floor plane. Note that we can activate the material preview in the 3D working area, as well, by clicking on the corresponding icon located on the top right corner of every 3D window. On the bottom, the wood material to apply and on the top, the Material Preview icon activation surrounded. Right: a preview render. Note that the brightness of the bulb has been increased (up to 140)

It is now time to work on the material of our candle. Caution: this part is a bit CPU-intensive. The Subsurface Scattering (SSS) requires significant calculations, so it is recommended that you deactivate the automatic preview of materials in order to improve the performance. Let's select our candle and go into the Material Room. Change the color of the "Color" layer to a beige-yellow color. Then, let's go to the Subsurface Scattering layer. Of course, do not forget to enable it by checking the appropriate checkbox. We will pay attention to three parameters: The Color, which defines the hue the object will appear at the light scattering level. The Translucency, which allows you to make this hue more or less translucent. The Refraction index, which controls how strong the light absorption effect will appear. (this is the main parameter) Let's start by modifying some of these parameters: First, let's decrease the Refraction index value, to make our wax more "absorbent" and define the absorption color. The orange color looks pretty good. Feel of course free to choose the color that best fits your taste! Then, increase a bit the default translucency. The different starting parameters of our wax material.

A first render creates the result shown on the left below. We effectively see an "SSS" effect, but it is far from perfect. A second render, with some adjusted values (higher refraction index, etc.) gives the result shown on the right below. It looks better, but the effect is now too bright. Is there a special trick you need to know? Two render tries. Left, the effect is too light; Right, it is too strong.

Yes, there is a "trick"! To get a much more realistic effect, we just need to activate, in the Rendering parameters, the Indirect Lighting (or "Global Illumination"). Let's launch a new render and see the difference: Left, with no Global Illumination. Right, with.

The effect now looks more convincing, but is still too bright. Below are the parameters used for the final image. Caution: they might be not exactly the same for your own model. The Subsurface Scattering is sensitive to the size of the objects (that is why there is a Scale Factor in the material parameters).

Before getting to the flame creation, think about creating a dark black material with a very tiny specular intensity for the wick. This part being pretty easy, it is not described in this tutorial.