Exploring Character Art Workflows: Skin Texturing Tips

Exploring Character Art Workflows: Skin Texturing Tips

3D artist Wooper discussed his general workflow for 3D characters and demonstrated some of the steps in the timelapse videos.

Introduction

Hi! My name is Wooper, I'm a 3D Character Artist and I create characters in 3D for VFX productions and myself.

During the last 6 years, I was a Motion Designer and 3D Generalist but from this year onwards, I've been focused 100% on characters.

I created characters for a Ubisoft trailer and I'm currently working on two projects, a professional project for a famous luxury brand to create an iconic celebrity in 3D and a tutorial on realistic face creation.

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Getting into Character Art

When I was a child, I wanted to be an artist and I tried different things to find my calling in 3D. I started 3D animation studies after high school because I loved drawing, 3D animation films, and game cinematics. I remember that during a production meeting for our short film at school, my teacher asked "Who made this character?". I quietly said "Me..." and she said, "Ok, you’ll be in charge of the characters, I want you to make all of them". At that moment, I realized that I could do something related to character modeling and that it could maybe become my job.

But it’s not so easy! When I finished my studies and entered the professional world, I realized I wasn't the only one creating characters and looking for a job. The harsh reality is that many 3D artists want to create characters but there aren’t many job offers. A production hires 3D character artists who have a lot of experience and it takes a while to acquire skills.

So I was waiting in the shadows and the door to motion design opened to me. During the last 6 years, I worked for motion and 3D generalist freelance contracts. Between contracts, I tried to continue self-training using tutorials and stay focused on 3D character creations.

It was so hard to motivate myself during the first years because playing video games is an easy way to forget your problems and not confront them. But after many attempts, I finally found my way, and one morning, the first thing I did was turn on my computer, open ArtStation, Pinterest, Google... and search for some references. Then I saw the Knight course by Huifeng Huang. It was expensive training but I took the risk. Then followed some other tutorials, and I started working on my project Geralt of Rivia.

It was a good experience, I had a 3D basis but I needed to improve my skills and workflow. In order to do that, I took some courses on anatomy, read articles, watched videos, and experimented a lot.

Inspiration

As time goes by, we create a library in our mind filled with what inspires us. Year after year, I feed this library simply by looking at some references, projects of different artists, studios' works. I like the fact that we can do so much with our imagination – we can deform reality and create something new. Sometimes we can't do this in real life but 3D makes this possible. I personally like the fantasy style but really close to or inspired by reality. Realistic models and textures are important to me. Creating what doesn't exist in our world but would be real in another is like creating a new life...

Among the artists who inspire me are Raf Grassetti, Ian Spriggs, Nikolay Demencevich, Marek Okon, and Shuo Shi. I'm also often inspired when I watch some trailers like the ones for League of Legends. Riot Games makes sure that each character has a story and that’s what makes them interesting. The studios convey these stories in their trailers, with good music, animation, and post-production, and it looks amazing. Blizzard and a lot of VFX studios like Unit Image inspire me too, they make awesome cinematics with good staging and beautiful artistic direction.

All these inspirations influence my work and motivate me to try to create characters with the same quality.

Work with Reference

A 3D character doesn't start with a polygon or a sphere in ZBrush. First, I always prepare myself mentally and start to write down all the features of the character in a note.

Important ideas to write down before starting a character:

  • Gender of the character
  • Age; it determines maturity and affects the look of the character
  • Location and time period
  • Job and social class
  • 3 main personality traits
  • 3 main elements of the body
  • Character's story if possible
We can't do anything without references and thinking otherwise is dangerous. Even Leonardo da Vinci had references, his Mona Lisa is a famous example. I create the first moodboards quickly on Pinterest, sort them out a little, download all the references, and upload them in PureRef so that they stay on my screen all the time.

After writing down my character's features and finding my references, I can start working on the character because I know what I have in mind. This way, I can avoid redoing the project and losing time. Of course, I change some little things to improve the look but it's important to determine what exactly you need to fix in order not to lose yourself in the darkness of retakes.

In professional productions, it can sometimes be a big mess because the clients don't always know what they want and forget that we simply follow a brief or a concept. So I try to get all the information I need in order to reduce the number of retakes.

A character like Geralt of Rivia is the simplest task because the character already exists. But I still need to find references, group them by type like hair, armor, swords, face, and sometimes other details like scar and eyes that make the character recognizable.

Sculpting in ZBrush

I first started sculpting with clay and then learned ZBrush at my school. Our drawing teacher taught us some anatomy too. Knowing anatomy is important but I needed to work on my observational skills and it took a lot of time. I read some books like the atlas of the anatomy, observed and drew bodies, and studied the works of other artists. Don’t be afraid to draw and sculpt naked bodies for practice because this is the best way to improve your anatomy knowledge and train your eye. As I said, the mind is a library and it needs to be fed by observing things. And don't blame yourself when it looks poor because it takes years of practice to become good at anatomy.

Basically, I start my sculpts from a sphere and sculpt with Dynamesh. The polycount for the final result is very high but I do a retopology in Maya to simplify the mesh.

In this timelapse, you can see how I created Jane with this process:

In order to save time, some professional 3D artists start sculpting with a base mesh but it's a very big mistake when beginner sculptors do the same. I know it can be frustrating but it's very important to learn how to get good results. You need to understand the muscles and bones and how it all works. To start sculpting in ZBrush, I recommend recreating existing characters. This is the easiest way to observe the model and understand how to use the tools.

After sculpting, I use the retopology method to create the low poly and bake the maps for the new model. For retopology models, I sometimes use a preset mesh I created previously or a base mesh – I just need the eyes, nose, ears, and mouth with a good number of polygons that I can snap easily to the model.

Skin Texturing

I need four maps to get a nice skin – the color, of course, the displacement map, the specular, and the SSS map.

To create my skin texture, I use a Texturing XYZ multimap, it works very well for applying a realistic texture to our mesh. It includes a color map and a multimap with displacement, specular, and SSS in the RGB channels. After the retopology and UV mapping, I wrap this texture around my mesh.

Then I need to bake the texture with xNormal. I apply the texture to the model in Mari, adjust the final details for the multimap, and add some more details with other realistic textures. The most important and visible part of a character is the face but for the rest of the body, I use Mari too and project a realistic texture on it. In this video, you can see how I used this process to create the skin texture for Jane:

A realistic skin is not enough for a good result, I also need to add some details in the displacement map like wrinkles, scars, or spots in ZBrush. I also add dark circles under the eyes and freckles and adjust the other details in Mari or Substance Painter sometimes. Imagine this process as applying makeup – with a simple color brush we can create a lot of details on the body and the accumulation of these details forms a good texture.
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Finally, I add my texture maps into a aiStandart shader in Arnold. It's important to understand how Maya and Arnold work and process these maps because it might drive you crazy.

Here is a very good tutorial by Akin Bilgic which helped me to calibrate the settings in my displacement export when I couldn’t figure out the displacement map.

Eyes

It’s crazy how the eyes can make you feel emotions. We can get the impression that the character is watching us or looking at something in the distance, and then we want to find out what they’re looking at.

Eyes are part of the body and it's very important to understand how they work to make them beautiful. They are not really spherical but to simplify rigging, I make the eyes spherical. I create two spheres; the first bulges a little to simulate the cornea and I apply a shader with transparency and a reflection to it. The second is a little smaller with a hollow, which simulates the iris and the pupil.

The iris needs details if we ever zoom in on the face. It is composed of many colors, including one or two main colors but never one only. For the final touch, I add a volume with a little displacement when it's necessary.

Hair

In order to generate hair and fur, I use Xgen in Maya – this software is good but can be unpredictable, so it might be difficult to work in it at the beginning. But once you understand the process, it becomes easy to use.

Before starting to generate the hair, I always make a sketch to separate the different parts of the hair and make a volume base in ZBrush. All characters have different haircuts, it's part of their personality and it's a way of differentiating them from others. Then, I create some curves by following the direction of the hair and I snap them to my ZBrush base model. The last steps before creating my collection in XGen is to isolate the scalp of the head, make a new UV for it and assign a new white shader.

I recommend separating the grooming scene from the master scene because it can be heavy. When your grooming is finished, you can import the rest of your master scene in the XGen scene. But I prefer to "convert to the interactive groom" and export it in alembic in my master scene to avoid problems.

Finally, I create my collection and some descriptions of the hair and fur in XGen. In the description, I convert my curves into a guide and assign a map modifier and expressions to create realistic hair. The maps determine the zone of the generation or the zone of the effect. The modifiers alter the behavior of the hair and you can add some maps and expressions to control them. It's a long process and a lot of simulation tests are necessary to get a good result.

In the video below you can see the process I used to create Jane's hair, eyebrows, and eyelashes:

Lighting

Basically, I use two methods to light my characters. The first one which everyone knows is HDRI lighting. It's a very good and simple process to light a character without wasting time. But the drawback of this method is that you can't control the light – maybe you can add some lights to adjust a shadow but it's still an environment that you can't control. It’s like in real life: you can't move the buildings, the sun, the trees...

The second method that I utilized for Geralt and Jane resembles the one used in photography studios, three-point lighting. I create my own lights and adjust the position and the intensity the way I want.

  • One key light: it is the most intensive light. I place the main light above the character and a little slanted, just to highlight the features under the brow bone and facial features. It needs to be high and with a big intensity to cover the features.
  • Back lights to highlight the shape of the volumes and play with the SSS of the ears. Two (or just one light) behind the character can be useful to highlight the volume and focus the viewer's attention on the character.
  • One fill light: it is big but not as intense. It highlights some shadows because they can't be very dark. The light is placed far away from the character, with a big scale and intensity twice as less than that of the main light. The position will depend on the shadows that the light needs to fill. It's also needed to play with the reflection in the eyes to create a little white spot in them.

When I'm testing my lights, I always use a lookdev kit or just spheres with white, gray, and chrome shaders. They are helpful to observe the behavior of the light on the objects. If the sphere is overexposed or too dark, I can directly adjust the brightness.

The understanding of photography is important for creating good lighting in a scene. I studied photography when I was a child and I never thought this knowledge would become so useful for my current job.

Setting Up Specular and SSS Maps

Of course, the behavior of the light depends on its intensity and position but the most important thing is the shader. Shaders reflect the type of the materials with the absorption or diffusion of the light and we need to set them correctly to recreate the material we want. It can be adjusted with a texture map or just a value.

Every material has its own settings and maps but the settings that most important for recreating the physical behavior of the light are the specular and the subsurface for the skin. The specular affects the reflection of the lights and the SSS influences the translucent aspect of the shader. The SSS is very useful when it comes to creating skin, wax, or organic materials.

Like I said before, I need four maps to get a nice skin result: color, displacement, specular, and SSS. I connect my texture maps in two aiStandartSurface shaders in Arnold, one for the specular and the other for the SSS treatment. Then I connect them in one aiMixShader.

These two parts determine our texture. In specular settings, we plug the specular or the roughness map. With black&white information map, it determines where to absorb or diffuse the lights. With just these settings you can get the first results of the material.

The SSS is the most complex map. It determines the translucent aspect of the skin and is calculated using a brute-force ray-tracing method. We need to plug in the SSS map to influence the zone and radius where the light needs to cross the mesh or not. Connecting a color map in the Subsurface Color influences the color's translucent aspect. The radius is influenced by the scale of the mesh in the scene so the Scale value in the SSS can be changed. The last setting is Random Walk that's activated by default in the type settings; it's important because it determines the type of our translucency. For example, Random Walk V2 is highly transparent and it can't be used for the skin but might be suitable for wax objects.

The last step is to connect the displacement map and adjust it. The displacement adds some volume to the skin, the pores, the wrinkles... Be careful to work in Raw and activate alpha illumination before rendering.

Arnold is very good for the skin but it is more powerful for the hair shader. With the aiHairStandart, we can directly apply the hair type we want with the presets and directly adjust the melanin value. The melanin determines the color of our hair so Jane, for example, has a low melanin value and her hair is polar blond.

To recreate materials closely, it's important to know the shader settings. For all rendering software solutions, you can find documentation on the official websites – that's the best place to start.

Afterword

I think the biggest challenge was to arrive at where I am today. This challenge continues day after day – to outdo me to improve my skills. Throughout all these years of freelance work, I lost motivation, doubted and questioned myself several times. Year after year, it was harder and if I didn't believe in myself I wouldn't have been here today. Creating good characters takes a long time and I need to be patient, work hard, and not give up.

The best days were the days when I got up, sat at my desk, listened to epic music, looked at some works that inspired me, and then started to create forgetting about all my worries and believing only in myself. Even though it's hard, my goal is to reach the time when every day will be like that. The process takes a long time and each hour is precious.

Wooper, 3D Character Artist

Interview conducted by Ellie Harisova

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