Secrets of Swimsuit Babeby Jimmy Chow, Hong Kong
There remains diffuse and epidermal channels. Most of the color variation is put
into the diffuse channel and epidermal color remains monotonic for most part of the
body as shown in figure below
As mentioned before, ZBrush 2 was used to texture the body by projection. In Photoshop, Nagel Series 37 Brushes (see appendix section for download URL) were used to do the painting. The brush size is huge. You need to reduce it a lot. After painting, the texture was further processed in Photoshop: flip vertically, duplicate layer, change the new layer’s blending mode to multiply and opacity to 60%. This would make it look more saturated. Then save it as TGA format. Finally the TGA file was converted into MAP format using the imp_copy command. There’s a batch file to perform this conversion:
Because there’re three pieces of textures for a single channel, they must be combined before being connected to the channel. It can either be done manually in Photoshop or procedurally by using a utility node. The latter is adopted and the node is mix8layer (see appendix section for download URL) as shown in the figure below:
The three textures are connected to the first three layers in mix8layer and the opacity of second and third layers are controlled by two checker textures so as to exclude other layers. Although it is convenient to put textures into the network without combining them in Photoshop, there’s a cost to pay because this network will take time to calculate during rendering.
Lastly, the resolution of the light map texture is driven by an expression as they depends on the resolution of the output image. The expression is shown below:
mentalrayTexture1.miWidth = defaultResolution.width * 2;
mentalrayTexture1.miHeight = defaultResolution.height;
Specular and Rim Reflection
I’ve found the specular calculated by sss fast skin make the skin look too waxy and its reflection doesn’t seem to be correct. They also take so long to render that it’s wasting time to experiment. So they’re rendered in separate passes with different shaders and are tuned in Shake.
For specular, create a blinn, turn off its diffuse and reflection, connect a texture to the specular color channel and you’re done. The color is shown in maps image. Rim reflection is due to fresnel effect. It cannot be faked with facting ratio. So the ctrl_fresnel shader was used to produce this effect. (Refer appendix section for download URL.) But the rendered reflection must be adjusted significantly in Shake as its edge adjacent to the skin is quite sharp.
Eyes
A procedural shader is used to texture the eyes and it involved the sss fast simple
shader for the whites in the eyeball. There’s a trick which casts an artificial shadow
over the top of the eyes by projecting a ramp using a projection node. It is connected
to the diffuse channel in the sss fast simple shader and multiplied with the shader
representing iris. The following figure shows how the shading network looks like:
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