Shading Jim in Cycles
Now that you have a basic understanding of how Cycles materials work, let’s jump right in and use shaders to make Jim look great!
Basic Shading
Cycles materials are more complex to render than Blender Render materials, so you may want to add one or two lights to be able to see your scene when you switch from time to time to the rendered mode display in the 3D view to preview how everything is looking.
1. Select Jim’s face and add a new material called Jim_mat. Add a Mix Shader to it and, for the first slot, pick a Diffuse BSDF shader. In its color field, load Jim’s textures as an image and make sure the Vector is set to Texture Coordinate | UV. The image may look a little dark, but don’t worry; it’s because the other half of the material is still empty and you’ll make modifications later.
2. For now, select all the objects that use the textures and then select the one to which you just added the material, press Ctrl + L, and select Materials. This will make all those objects use the same material.
3. Add a material to the hair elements called Hair_mat and set its Surface as a Diffuse BSDF with the blue color from the designs.
4. Select an eyeball and follow the same steps you followed to add materials to its parts with Blender Render (you can find the instructions in the earlier section, Adding Several Materials to a Single Object). Create four different material slots in the list and call them Eyeball_mat, Cornea_mat, Pupil_mat, and Iris_mat. For the pupil and iris, add Diffuse BSDF shaders with black and blue colors, respectively.
5. The cornea and eyeball will be a little trickier. For the eyeball’s material, add a Mix Shader. Select a white Diffuse BSDF in the first slot and a Glossy BSDF in the second slot. Adjust the roughness of the Glossy shader to 0.5, so the shine is more blurred.
6. For the cornea, add a Glass BSDF shader. Give the Glass shader’s color a light-blue tone, increase the IOR (Index of Refraction) to 1.38 (similar to what you did in Blender Render), and set the roughness to something very low, such as 0.03, so that external light sources are reflected in the eyes to create a visible “catchlight.”
7. The cornea is really dark and this is because even though it’s mostly transparent, it’s casting a shadow in the eye’s interior. To correct this, go to the Object tab in the Properties Editor (the one with the yellow cube) and, at the bottom under the Ray Visibility panel, turn off Shadow. This feature will prevent the eyeball from casting shadows and now the cornea will look completely transparent.
Advanced Shading
A few more steps are needed to finish the shading of Jim using Cycles. You need to adjust the material that uses the textures so it works properly. Remember the Mix Shader you added to those parts of Jim that was half empty? Let’s work on it.
1. In the second slot, pick a Glossy BSDF; this will cause the material to reflect light.
2. Load a couple more textures to control the effect of the Glossy BSDF shader’s properties. Take a look at Figure 10.8 to see the textures that you will load. The one that controls the Mix Shader Fac is the same one you used for the Specular Intensity in Blender Render: a grayscale image in which the white areas will be shiny and the black areas won’t.
3. Finally, in the Roughness for the Glossy BSDF shader, you’ll use yet another texture. This one is similar to the Hardness value in Blender Render, but this parameter controls roughness, where white in the texture is rougher and black is smoother; this means that it is the opposite of the BI Hardness. In Figure 10.8, notice that in the texture to the right, there are some darker marks; those will be areas with a sharper shine.
4. Adjust the material nodes in the Node Editor to arrange them. Unfortunately, when you load these types of textures from the Properties Editor, they automatically pick their Alpha value, but you need to use their color and there is no other way to do it than by using nodes. For that, follow the next steps to make some basic adjustments to the material nodes.
5. Select an area of the interface and switch it to a Node Editor. It should automatically show the current material nodes. If this doesn’t happen, select the object with the material you’re adjusting. Then, open the Node Editor and if Material nodes are not displayed by default, look in the Node Editor’s header for a three-icon row that shows a sphere for Materials, a checkerboard for Textures, and a couple of layers for Compositing; click the icon for Materials.
6. In the same header, select Jim_mat in the Material list. Then, arrange the nodes because right now you’ll see them all on top of each other. (This is a side effect of working in the Properties Editor with Cycles Materials: the nodes are all created in the same place.) Left click and drag them around until you can see the tree clearly (see Figure 10.9 to get an idea on how this should look).
7. Once you can see all the connections in a structure similar to the one in Figure 10.9, reconnect the marked lines as shown in the image, so the Color of those two textures is used instead of their Alpha. Left click and drag over the little dots at the sides of each node (input and output noodles) to reconnect them.
8. Finally, adjust the material for the clothing details by adding a Glossy BSDF to the second slot, setting the roughness to 0.15, and then reducing the Factor of the Mix Shader to 0.1. This will make those pieces of clothing look similar to the other details that are inside the textures.