Blender 3d Hair guide

Introduction

The representation of the human being in the audiovisual medium has emerged as a central issue in contemporary society. Leading animation companies, such as Disney, have sparked intense debates by seeking broader inclusion in their films and series in recent years. However, every individual should be reflected equally in entertainment such as video games, series and feature films.

This guide contains visual examples of all the different types of human hair. They have been made on busts from the ZBrush library, with particle systems using Blender.

The classification of humans by geographical areas and ethnicity play an important role in the origin of different hair types. This means that a relationship needs to be established between them, both to understand where they come from and to aknowledge their behaviour and style.

It must be taken into account that any human being can have any type of hair, as it is a genetic component that is not exclusive to a single area. The aim is to generalise in order to better understand its origin and extent, but we must never make the mistake of assuming that there is no mixture.

We need to understand these concepts, so an investigation has been made and it's going to be explained below.

In order to understand how the hair types will be named, there is going to be a short description explained:

1a Straight (fine) Very soft, shiny, hard to hold a curl, hair tends to be oily, hard to damage.

1b Straight (medium) Has much body. (i.e. more volume, more full).

1c Straight (coarse) Hard to curl (i.e. bone straight).

2a Wavy (loose waves) Can accomplish various styles. Loose "S" pattern. Hair sticks close to the head.

2b Wavy (defined waves) A bit resistant to styling. Hair has more of a defined "S" pattern. Hair tends to be frizzy.

2c Wavy (wide waves) Hair has wider waves. Resistant to styling. Hair tends to be frizzy.

3a Curly (loose curls) Thick and full with much body. Definite curl pattern. Hair tends to be frizzy. Can have a combination texture.

3b Curly (tight curls) Medium amount of space of the curls. Can have a combined texture.

3c Curly (corkscrews) Tight curls in corkscrews. The curls are very tightly curled.

4a Kinky-coily (defined coil) Tightly coiled. Has a very defined "o"-shaped pattern.

4b Kinky-coily (z coil) Tightly coiled. Little less defined kink pattern. Has more of a "Z"-shaped pattern.

4c Kinky-coily (tight coil) Tightly coiled. Almost no visible defined kink pattern, unless seen from up close. Has more of a very tight "o"-shaped pattern.

Asia and America

The first area to be investigated will be Asia and America. In order to understand the origins, we will begin to talk about the American continent prior to the conquest of Christopher Columbus in 1492.

Thanks to palaeontology and the collection of human remains dating back to that time, researchers have been able to determine what kind of DNA humans carried more than 500 years ago. It is estimated that the population was between 8 and 112 million people across the continent. Thanks to this data, it has been possible to reconstruct what they looked like and to represent them in various ways (Denevan, William M., 1992).

Both northern and southern natives have a characteristic straight, thick, coarse and dark hair, belonging to a 1c type. At the same time, they also show many variations in shape, so that all the variants of straight hair that have been studied could be included in this category.

Regarding the Asian continent, the eastern area shares the greatest number of similarities with America, this being a place of black and straight hair. The northern area, which is closer to the European continent, also shows little variation in terms of waviness, but the thickness of the hair decreases and the colour becomes lighter, with even reddish tones being common. Therefore, it can be concluded that in this region straight hair of all levels and shades predominates, meaning 1a, 1b and 1c types.

Europe and India

The Mediterranean area loses the thickness of a 1c hair, and replaces it with natural waves that are not very pronounced. Although the area around India is in Asia, and some northern parts of Asia do have this coarser, darker hair type, the southern part adopts the characteristic waves we are talking about.

Therefore, types 1a, 1b, 2a, 2b and 2c can be found in this geographical area.

North Africa, Australia, Micronesia and Polynesia

In the North African area, tight curls and pronounced waves begin to form. As the area is much closer to the north and Europe, the characteristic curly and short curls of the central and southern area starts to disappear. The same is true for people from the islands located on the oceanic continent. Therefore, the types of the category 3; 3a, 3b and 3c are predominant.

Central Africa and South Africa

As previously mentioned, the central and southern African zone composes the largest number of people with curly hair in category 4. They tend to be dark and strong, and are usually styled in braids. However, the aim of their realisation in 3D is to observe the hair mainly in a visual and not very confusing way, otherwise it is not possible to observe its shape and function properly. So, for these regions, 4a and 4b are to be seen much more often.

Melanesia

Finally, the Melanesian area, distinguished by having the curliest hair type of all. In its people, a wide range of colour is observed, somewhat more distant from what could be seen as the traditional dark African hair. Therefore, it will be taken as the best example to show type 4c.

3D hair examples made with Blender

1a & 1b

From left to right; 1a (female), 1a (male), 1b (female), 1b (male).

1c & 2a

From left to right; 1c (female), 1c (male), 2a (female), 2a (male).

2b & 2c

From left to right; 2b (female), 2b (male), 2c (female), 2c (male).

3a & 3b

From left to right; 3a (female), 3a (male), 3b (female), 3b (male).

3c & 4a

From left to right; 3c (female), 3c (male), 4a (female), 4a (male).

4b & 4c

From left to right; 4b (female), 4b (male), 4c (female), 4c (male).

Particle hair creation in Blender: an easy guide

A small study has been carried out on the workflow of hair creation.

Several websites and 3D references (such as ArtStation, UnrealEngine, Blender, etc.) have been consulted and useful information has been extracted to improve the creation of the hair.

Although the methods of hair creation for video games and animation are different, we have tried to unify them in a general workflow.

1- The first step is to look for references and do a little planning of what the desired result looks like. To do this, some related questions will be asked, such as the direction of the hair (where do you want it to go?) or the way in which the locks are parted, and the type and characteristics of the hair (shape, volume, curl...).

2- Next, choose the hairstyle you want to create; the silhouette, and how this is going to be integrated with the model and the character.

3- Placement of guides (or particles). In this step the strands of hair are placed on the model and combed. The desired shape is achieved, and the density and irregularities of the hair must be taken into account. On the head, not all hair is the same length. Some are naturally longer than others, and this is more noticeable on the head. In addition, variations in curl are also established. Even if a hair falls into a particular category, human genetics are not perfect, and inevitably hair does not have the same curl all over the head. Some areas are smoother than others, and if harmony is to be achieved, asymmetry in the particles must be implemented.

4- Finally, applying textures. With the help of the reference, the brightness and colour that the rendered hair is set. Variations in colour must also be included, as naturally the hair will show discolouration in the older (grown) parts due to the sun's rays, which naturally lightens them. Not all hairs are the same colour either, and this should be reflected in the final rendered result.

The first step in this guide for the creation of the 3D hair was to choose a base to work with. Therefore, it was decided to use the base models provided by the ZBrush tool, making some slight modifications to differentiate a more "masculine" face from a more "feminine" one.

Introduction to Zbrush

The first thing that is shown in the ZBrush menu is a library of assets, with which to work in the program. The female bust was chosen as the basic one, as it will simply serve as a "mannequin" to place the hair on the bust. The chosen bust has been modified in the Zbrush program itself to obtain a similar version, but one that more closely resembles a male face.

Once the models have been made, they will be exported in .obj (a type of 3D file that facilitates the importation of geometry from one program to another) and imported into Blender for the realisation of their hair.

Introduction to Blender

The main software to be used in this project is Blender; a free tool for the development of 3D, 2D, texturing, rendering, rigging, etc. projects. This tool will allow the creation of particles on a base bust, its styling and subsequent rendering.

Hair creation

The first step in the creation of hair in Blender has been the import of the OBJ file previously saved in the program. Both busts are in the same joint file to make their creation easier, as the sizes of the elements can be adjusted more easily, the particle system created, and so on.

Once the material is ready, we will proceed to select the part of the model we want to work on. To create the particles, we have chosen to use a "scalp", i.e. a part of the geometry of the model that will act as a "scalp". As the male and female models share most of their geometry, only one scalp needs to be created and duplicated for use on both models.

To create the scalp, the first step is to set "edit mode" in Blender, which will allow access to the geometry of the model. In this mode, the user will be able to select the number of polygons in the geometry to separate them from the model and thus create the base with which you will continue working.

Particle systems

Once the scalp is separated and selected, a new particle system for the scalp is created in the "particles" menu. Select the option "hair" and the scalp will be covered by particles.

In order to check the parameters of the particle behaviour, the first step is to check the "emission" section. Each of these parameters makes the following changes:

-Number: The number of base particles to work with.

-Seed: The randomness with which the particles are set.

-Hair Length: The length of the particles.

-Segments: The number of segments found per particle. This will allow better shaping of the direction and shape of the particles.

Next, use the "children" menu, which is used to interpolate more particles between the ones already created, to add the desired volume to the hair.

-Simple: Interpolate using the base particles as strands.

-Interpolated: This time the extra particles will be rearranged between the base particles.

Within each of the options there are parameters that allow you to control the behaviour of these children particles. Some of the parameters that will be used are the following:

-Display amount: The amount of children that will be displayed.

-Render amount: The maximum number of children that will be rendered.

-Length: The length of the particles.

-Seed: The randomness with which the particles are set.

Below, another important menu is shown; the "clumping" menu. It serves to bring the tips of the created particles closer together. A positive clump will bring the strands together at the ends and a negative clump will bring them together at the roots. "Shape" will indicate at what point these hairs will start to come together.

The next menu is the "roughness" menu, which has been divided into three parts. The first affects the whole length of the hair; if we increase the "uniform", the hair starts to wave, "size" controls the length. The "endpoint" affects the ends of the hair, and "shape" controls at what point in the hair's length these changes occur. Finally, "random" is similar to "uniform" in the first category, except that in this category there is "treshold", which allows you to choose how much of the hair changes, i.e. if you increase the number by half, only half of the particles will form a wave, while the rest will remain straight.

The next menu is the "kink" menu. Each of these menus indicates whether the hair shows some kind of curl. Each one is different, and shows its own menu for its corresponding edit.

Below is the "hair shape" menu.

-Strand shape: modifies the thickness along the length of the hair.

-Diameter root: indicates how thick the root of the hair is.

-Tip: indicates how thick the tip of the hair is.

-Diameter scale: increases the thickness of all the particles.

Finally, the "vertex groups" menu. This menu allows you to control the amount of alterations to the particles according to the weights assigned to them. For example, if we paint an area with a high intensity in the centre of the head and low intensity at the edges, and we set the profile to lenght, the part with the highest intensity, i.e. the top of the head, will have a long hair, and as it gets closer to the edges that hair will decrease in size. You can assign any profile and modify these particles with the same profile.

Texturing

Once all the particle generation has been completed, the next step is to texture them.

This texture will be generated using nodes. Blender has a special type of node for hair, so it will be used by modifying the settings.

In this case the Eevee render engine is selected, although it will only serve as a guide for the texturing preview.

The parameters will modify the colour, mainly in terms of the amount of melanin. Roughness will be used to change the highlights of the hair; making it brighter or duller.

In addition, a little colour was given to the busts, as only grey did not convey an aesthetic coherence.

Finally the rendering will be executed with the Cycles engine.

This guide has been made to allow artist to have a better understanding of the origins of human hair; how it works, where it's from and how it looks in 3D.

Different types of hair on characters enrich their appearance and background, as well as giving them a more innovative and distinctive personality. We encourage you to use this guide for your creations!

Thank you for reading.