Making Of 'Cereal Killer'
I had in mind a man tied to the world of culture - someone like an architect, beatnik or philosopher. An eclectic character with a disquieting look together with a touch of humor: a seriously cynical, yet funny man (Fig.01).
My father patiently agreed to be a model for the photo references I needed to start modeling the face and hand.
The software I used was: Maya, ZBrush, UV Layout, Mari, Shave and Haircut, V-Ray for Maya, Nuke and Photoshop.
I started with a base mesh of the face in Maya with a topology that suited me (Fig.02).
I did the same thing for the hand (Fig.03).
I continued to add the other objects until I achieved the final composition (Fig.04).
Before starting sculpting I created the UVs for all the objects with UV Layout.
In this part of the tutorial I will focus on head sculpting. I started using the ClayBuildup brush with an alpha 48 to do the main shapes and the Move brush with a rather large size to create the small asymmetries that make the physiology more natural.
When I got to the fourth or fifth subdivision I changed the brush alpha to a smaller and smoother one (like 45 or 44) and I started to increase the intensity of the folds and wrinkles. This is a very important stage because the character starts to gain his own expressiveness.
In this work I decided to emphasize the procerus muscle, the corrugator supercilii and the orbicularis of the eyes in order to achieve a more serious look. I also focused on the orbicularis of the mouth, adding the typical smoker's wrinkles. I paid specific attention to the neck to create the effect of old and sagging skin.
Around the sixth/ seventh subdivision I fixed the smaller details. I didn't use specific alphas apart from the areas where the pores are more visible and the skin is more oily (nose tip, procerus, cheeks and chin). Here I used a particular one that I made from a picture of an orange skin, which I modified in Photoshop.
Next I applied a low intensity surface noise to the whole face and then I started to make the wrinkles more definite with the Slash brush. In the end I used the Smoothpeaks brush to reduce the bumpy effect; eventually you can exaggerate a bit with the intemsity of the surface peaks because the VrayFastSSS 2 will tend to soften the effect. This is the final sculpt (Fig.05).
Once I was satisfied I exported Displacement, Normal and Cavity maps with the MultiMap exporter (I used the Cavity map as a mask in Mari, therefore my advice is to increase the Blur amount in the export setting).
For the hand I used a slightly different technique: for the sculpting I went up to the fourth subdivision, then created the texture with Mari, modified it with Photoshop, and used it as an alpha (after I subdivided the model up to the sixth/seventh subdivision) to create a fine displacement (Fig.06).
In this part of the tutorial I will focus on the face texture. In Mari I projected the pictures of my father that I'd taken previously, and with a little patience, and the intelligent use of the edge mask, I created a good base texture. At this point I added a few layers to the shader in Diffuse Blend or in Masked constant color to add a bit of red to the nose, chin, upper and lower eyelids, and a bit of purple to the eye circles. I then added a layer of veins with a very low opacity. I imported the ZBrush cavity and I used it as a mask to give a better emphasis to the displacement of the pores and wrinkles (with a soft red and a very low opacity)(Fig.07).
What I like most about digital lighting is the chance to create lighting links, and, in a certain way, fake the lighting to reach your own purpose. First of all I created a circular environment on which I projected a texture of a room similar to my background to perk up the reflection of the objects. Following the lighting mood of my background I chose a four-light setup: a main light from the left, a soft fill light from the right and two back lights (an intense one from the left and a weaker one from the right). This setup didn't give enough importance to the t-shirt (which I considered essential to represent the character), the cap or the objects in the jacket pocket; therefore I added a fill light and linked it only to those. The left back light was good for the face but not for the hand, so I decided to put in a separate light for the hand. I also added two lights close to the face to illuminate the geometry I created to simulate the moisture in the eyes. Afterwards I exported a pass for each light to have the best control during the compositing phase in Nuke (Fig.08).
The setup of the lights is as follows:
• Lights 1, 2, 5, 7 and 8: Main light and fill lights (Fig.09).
• Lights 3, 4 and 6: Back lights (Fig.10).
Before setting up the shaders I did a displacement check (Fig.11). In this part I will focus on the skin shader.
VRay Fast sss 2 is a fantastic shader that allows you to obtain the best results without creating too many maps. Now we walk into a section where there are not definitive settings even if you are modeling in real-world scale. Now I analyze the most important parameters for the Skin (pink) preset (Fig.12)
Prepass rate: Values below 0 cause many artifacts so it's better to use a 0 value, which is what I did during the test rendering. I switched to 1 for the final render, keeping in mind that the render time doubles.
Scale: Scale and Scatter radius are linked together and personally I prefer to use Scale and leave Scatter radius with the default value. This is one of the most important settings because it defines the model's scatter amount. Higher values are equal to high scatter and the shader starts to look like wax. There is no set parameter you should use; it all depends on your own taste.
Diffuse Color: Note that this value actually blends between the diffuse and sub surface layers. I left this value at 0, but eventually you can add a map to the amount to lessen the scatter effect in certain spots of the face.
Sub Surface Color: This is the parameter that affects the real look of the skin. I assigned the texture I created in Mari to this.
Scatter Color: Compared to the skin pink preset, I desaturated a bit the color (in this case too, it's a personal choice).
Phase function: This is a very important setting because it determines the scatter depth. High values produce a superficial scatter and low or negative values produce a deeper scatter. Most water-based materials exhibit strong forward scattering; that's why I used values between 0.7 and 0.9.
Specular color: I left this as a solid white color, even though many other artists use a light blue. If you need a specific specular effect you can control it through a black and white map.
Specular amount: I left the default value because it's physically correct, but if you want to obtain different specular effects you can lower it.
Specular glossiness: It's a fundamental parameter since it determines the amount of glossiness of the skin. At first I determined a basic overall value (from my experience between 0.350/ 0.45). The face skin doesn't have a solid glossiness all over since there are oily spots, therefore I used a map to control its intensity. To have the maximum control I used a layered texture with a basic grey (value of 0.4) and a map I layered over it in Lighten to control the highlights (nose, lips, chin, eyelids, forehead and ears).
Trace reflections: It is a value to check in order to have physically accurate reflections
Scatter GI: Another important parameter if you want to get realistic skin, although once it's checked the render times will increase.
Prepass blur: For a still render like mine I set the value to 0.1. This setting can be used in animation to avoid the flickering of scattered objects.
And this is the final look of the shader (Fig.13).
I preferred to model the cilias, eyebrows and sideburns to be able to control them better. With a lot of patience you can do this by modeling very thin cones, copying them and slightly modifying them. This adds a lot of realism to your model (Fig.14).
As for the hair on the ears, the clothes and the beard, I used Shave and Haircut and exported about 10 single passes in Nuke (Fig.15).
I exported the following passes from V-Ray: light passes of each light in the scene, diffuse, rawGI, SSS, specular, rawReflection, reflectionFilter, rawShadow, rawRefraction, refractionFilter, 2 multimatte with a few objects I wanted to change a bit, ambient occlusion, 10 hair passes, and ZDepth.
Once I'd composited it all (Fig.16) I used Photoshop to add the cigar smoke and I changed the color curves a bit.
This is the final image (Fig.17).