We'll now see how to make the shaders for the Gidiosaurus's eyes; they are composed of two objects, the Corneas and the Eyes objects, so let's start with the first one.
Enable the 6th and the 12th scene layers and select the Corneas object; in the Outliner, disable the Eyes object's visibility in the viewport to hide it, put the mouse pointer inside the Camera view, zoom to one of the eyeballs and then start the Rendered preview.
Let's start to create the Corneas material:
- Put the mouse pointer in the Node Editor window and add: a Material node (Shift + A | Input | Material), a Geometry node (Shift + A | Input | Geometry), a MixRGB node (Shift + A | Color | MixRGB) and an Output node (Shift + A | Output | Output).
- Connect the Color output of the Material node to the Color input socket of the Output node, then click on the New button on the Material node to create a new material and rename it
Cornea_bump. - In the Material window, expand the Render Pipeline Options subpanel and enable the Transparency item; in the Diffuse subpanel set the shader model to Oren-Nayar and the color to a bright orange = R 0.930, G 0.386, B 0.082. In the Specular subpanel set the shader model to WardIso and the Slope to 0.070. In the Shading subpanel enable the Cubic Interpolation item.
- Go down to expand the Transparency subpanel; set the Fresnel value to 1.380 and the Blend to 1.700.
- Go further down to enable the Mirror item in the subpanel with the same name, set the Reflectivity to 0.200, the Fresnel to 1.380 and the Blend to 1.500.
- Go to the Texture window and in the first slot load the image
eyeball_col.jpg, rename the ID datablock aseyeball_coland set the UVMap.001 as the coordinates layer; in the Influence subpanel set the diffuse Color channel to 0.200 and the specular Color channel to 0.200 as well, set the Blend Type to Color. - In the second texture slot load the image
eyeball_bump.jpg, rename the ID datablock asEyeball_bump, set UVMap.001 as the coordinates layer and disable the Color channel to enable the Normal one at 0.007; set the Bump Method to Best Quality:
The "Corneas" material nodes
- Paste the MixRGB node between the Material and the Output nodes; then, connect the Vertex Color output of the Geometry node to the Fac input socket of the MixRGB node. Click on the last empty field at the bottom of the Geometry node to select the Col item from the pop-up list (it's the name of the Vertex Color layer that has been created, and mentioned, at the beginning of the Building the eyes' shaders in Cycles recipe in Chapter 12, Creating the Materials in Cycles).
The gray color of the Color2 socket of the MixRGB node showing in the rendered preview at the location established by the Vertex Color layer output used as factor
In the preceding screenshot, the effect of the Vertex Color layer is visible: the two gray dots on the eyeballs are actually the crystalline lens areas filled, only at the moment, with the gray color of the empty Color2 input socket of the MixRGB node.
- Press Shift + D to duplicate the Material node, click on the 2 icon button to the right side of the name datablock of the duplicated node to make the material single user, rename the new material, simply,
Corneaand, in the Texture window, select the second slot texture,eyeball_bump, to click on the X icon button and delete it. - Connect the Color output of the second Material node to the Color2 input socket of the MixRGB node.
The completed "Corneas" material
Now, go to the Outliner and enable the Eyes object visibility in the viewport to show it:
- With the Corneas object still selected, put the mouse pointer on the first Material node in the Node Editor window and press Ctrl + C to copy it.
- Select the Eyes object and, in the Material window, select the
Eyeballsmaterial slot; put the mouse pointer in the Node Editor window and press Ctrl + V to paste the material node we copied before. - Click on the 2 icon button to make the material single user and rename it
Eyes. Add an Output node (Shift + A | Output | Output) and connect the Color output of the Eyes material node to the Color input socket of the Output node. - Go to the Material window and disable the Transparency item in the Render Pipeline Options subpanel; go to the Mirror subpanel and disable it.
- Enable the Subsurface Scattering subpanel: set the IOR to 1.340, the Scale to 0.001, the scattering color to the orange R 0.930, G 0.386, B 0.082 and the RGB Radius to the R 9.436, G 3.348, B 1.790 values.
The "Eyeballs" material SSS settings
- Go to the Texture window; select the
eyeball_coltexture and set the diffuse Color to 0.855, disable the specular Color channel and set the Blend Type to Linear Light; select theeyeball_bumptexture and set the Normal channel slider to 0.005.
The "Eyeballs" material texture settings
Now let's see the iris:
- Box-select both the
Eyesmaterial node and the connected Output node and press Ctrl + C to copy them; go to the Material window and select theIrisesmaterial slot, then put the mouse pointer in the Node Editor window and press Ctrl + V to paste them. - Make the duplicated node's material single user and rename it
Iris; change the Diffuse subpanel color to R 0.429, G 0.153, B 0.000, then go to the Shading subpanel and set the Emit value to 0.07. Go to the Subsurface Scattering subpanel and change the scattering color to R 0.220, G 0.033, B 0.032. - Go to the Texture window and delete (unlink) the two texture slots. In the first slot, load the image
iris_col.jpg, rename the ID datablockiris_col, and set UVMap.001 as the UV coordinates layer. In the second slot, load the imageiris_bump.jpg, rename asiris_bump, set UVMap.001 as the UV coordinates layer and in the Influence subpanel disable the Color channel and enable the specular Intensity and Hardness channels with value 1.000, then enable also the Normal channel with value 1.000. Set the Bump Method to Best Quality. - In the third texture slot, load again the
iris_bump.jpgimage; rename the ID datablock asiris_ST. In the Image Sampling subpanel, under Alpha, disable the Use item and enable the Calculate item. Set the UVMap.001 coordinates layer and in the Influence subpanel disable the Color channel and enable only the Stencil item at the bottom:
The "Irises" material and the Stencil item
- In the fourth texture slot, load the
iris_col.jpgimage, rename the ID datablock asiris_emit. Set the UVMap.001 coordinates layer and in the Influence subpanel disable the Color channel and enable the Emit channel at value 1.000.
The "Irises" material emitting (fake) light
Regarding the
Pupilsmaterial, it's a simple basic material with pure black as Diffuse color and the Intensity slider under the Specular subpanel set to 0.000 to be totally matte. - Save the file.
For the Corneas object: we created two copies of the same transparent material, but then we removed the bump from one of them, because usually a cornea has bumps due to the veins on the eyeball but not on the crystalline lens, that is smooth; the two materials are mixed, exactly as in the Cycles version, through the output of the Col Vertex Color layer.
Regarding the Irises material: the iris_ST texture, set as a stencil map, works as a mask for the following texture to appear through its black areas.
Although it could have been solved by simply leaving a blank material slot, I assigned a black matte material to the pupils; I preferred to assign a material anyway, to avoid possible issues in the following stages such as, for example, in the rendering of the character against an alpha backdrop, of the separated passes and in the compositing.
Note that the Corneas is the only material where I enabled the ray-tracing mirror, which in the character's skin and in the armor are instead faked, to obtain faster rendering times (the eyes are really a small surface to be rendered).