Melanin 0.45, pheomelanin 0
Melanin 0.45, pheomelanin 0.65
Melanin 0.45, pheomelanin 0.95
Melanin 0.65, pheomelanin 0
Melanin 0.65, pheomelanin 0.65
Melanin 0.65, pheomelanin 0.95
Example of green hair dye with melanin of 0.1
Example of red hair dye with melanin of 0.1
Shininess is all about the hair structure
To get hair with the correct shininess, you need to look at the geometry of hair. Generally, when most people think of hair, they think of it as a smooth cylinder. But when you look at hair under a microscope, you’ll notice it’s actually made up of up tiny scales that spread away from the root of the hair. Because of this shape, hair reflections actually have a direction to them.
The general glossiness of hair consists of two specular lobes. In previous hair shaders, V-Ray used separate controls for primary and secondary speculars. While this may have given you more control over each specular lobe, it also made it more challenging to find the right balance. In the new hair shader, the two speculars are linked in a more natural way and the general glossiness controls both lobes together. To enhance the primary glossiness, just raise the primary glossiness boost to get that extra shine.
Glossiness 0.45 with Boost 0.10
Glossiness 0.45 with Boost 0.50
Glossiness 0.45 with Boost 0.75
The highlight itself will follow along the length of the hair. But the highlight can also wrap around individual strands. This can be controlled through the softness parameter. The higher the softness, the more the highlight will just wrap around individual hairs and give it a smoother look. Lower softness values will make the hair look crisper.
Example of different softness
Softness at 0.10
Softness at 0.50
Softness at 0.80
Looking back at the microscopic image of the hair, you’ll notice that the scales on each strand face away from the root of the hair. If the scales are very flat, the highlights will appear more linear. If the scales are more angular, the highlights will bounce back more, shifting them slightly. This effect is controlled by the highlight shift parameter. The higher the value, the more the highlight will shift away from the root of the hair.
Examples of different highlight shifts
Highlight shift 0
Highlight shift 3
Highlight shift 8
Not every hair is equal
As you know, the shininess and color for each hair is not identical. Therefore, details such as texture maps can be introduced to control different colors. Also, many hairs right next to each other can have variations in their colors and highlights. This is where randomization can help.
Randomization parameters allow you to introduce variation between each individual hair, allowing for a certain shift in the amount of melanin, softness, glossiness and dye color. This will give you a much more realistic representation of the color and shine of the hair.
Example of random melanin color
Melanin randomization 0.0
Melanin randomization 0.25
Melanin randomization 0.50
Glossiness randomized by 0
Glossiness randomized by 0.25
Glossiness randomized by 0.50
Faster look development for hair with simpler settings and fast IPR with V-Ray GPU
With the fast feedback of V-Ray GPU in IPR, in combination with the new hair shader which is compatible with V-Ray GPU, you can render natural looking hair very quickly in V-Ray Next. The following image was rendered using the original scene from Ian Spriggs of his protrait of his friend Tony. After converting the shaders to the new hair shader from V-Ray Next, we were able to generate the look developement of the hair in a very short period of time.
Here is a video that shows you the process of using the shader for look developement of the scene: