Making a Snow Dwarf in ZBrush, Maya & Arnold

Introduction

My name is Enrique Mateo-Sagasta and I’m a Sr. Creature Modeler at Industrial Light & Magic. I have been passionate about movies since I was a kid, but I didn’t always have my career path clear in mind. Actually, before studying 3D, I finished my Law degree in Madrid, the city where I was born. After that, I did a small course to learn Maya. Then I worked for a communication agency where I did marketing and some 3D. It was then I decided to complete my 3D education and try to do this for a living. I packed my things and moved to Canada to study at Vancouver Film School.

Once I finished my one-year program, I was hired at Electronic Arts first to work on FIFA and Rainmaker and then – on the Barbie DVDs series. Yes, Barbie, I will always be thankful to that company because thanks to that job, I met some incredible great artists who I remained friends with until today. Secondly, the company did the paperwork for me so I was able to get my permanent residency in Canada.

After that, I jumped to VFX and was hired by Zoic, where I was working on TV shows (Zoo and Once Upon a Time) where I made my way up, from a generalist to one of the principal character artists. It was really fun to work there. Once I gained enough experience, I wanted to finally work on movies, and I got hired at Method Studios (Framestore today) where I had the chance to work on X-Men (new mutants), Ford vs Ferrari, Men in Black International, Dr. Sleep, The Witches, and the Christmas Chronicles. 

The Dwarf Project

Most of the projects I start are speed sculpts for practice. And most of them end like that, as a fast sculpt in ZBrush. By doing this, I practice how to lock primary and secondary forms fast. Those are the key elements for a believable character. Details will come afterward if you want to push it further, but you can't get a good sculpt if your proportions and secondary shapes are off. 

I based the Snow Dwarf on a concept from a great concept artist called Ivan Dedov, but I was not trying to make it exactly the same.

I started it during my vacation on my iPad in the Forger app.

After blocking something I was happy with, it was time to move it to ZBrush to polish the whole thing. There, I was able to improve my sculpt by fixing the main proportions and secondary shapes.

After that, I did the UVs of the geo from the iPad. I decided to keep only one UDIM for the whole head and use 8k maps from ZBrush.

Once I had good geo with UVs and was happy with the primary and secondary shapes, I duplicated them into ZTool. From that moment on, one would be the expression where I break the symmetry, and the other one I would use to create the details through HD geometry in ZBrush taking full advantage of the symmetry.

Something important to check before you move to any sort of detail is the scale of your character in the software you are going to render the whole thing. Skin shader is scale sensitive as are many other attributes inside any 3D package, so you want to keep the proportions as similar to real life as possible. With the basic geo in Maya ready, I threw a dome light in Arnold and started playing with different HDRI maps and camera positions. This way, I built the connection between Maya and ZBrush and kept updating the Maya file from there. This also gave me a break from the modeling stage and I could play with lighting to see what the best way to lit the character is to show off the forms. 

Going back to ZBrush, I started on the fine details in the symmetrical ZTool. For this part, I used HD geometry and custom-made alphas to add pores and wrinkles. I used the DamStandard brush a lot at this stage as well as a set of free brushes from the artist Raphael Souza.

Facial Expressions

Most of my practices are busts or faces, and for those to be interesting, they need to look alive. The way to do this is through interesting facial expressions. Facial expressions are controlled by a set of muscles in our face, there are lots of them, and they drive the movement of our eyebrows, mouth, eyelids, etc. I think the key for a good facial expression is asymmetry and the way the skin stretches or compresses. 

With the dwarf, for instance, one eye is more open than the other, and that translates into more wrinkles in the forehead area above the more open eye. There is an asymmetrical smile that is causing the wrinkles on one of the cheeks to be more pronounced. All this doesn’t seem much once the beard is in place, but without it, the face would not look as alive. Of course, gathering a great number of references is key.

Painting in ZBrush

I think what makes skin believable in GG is a combination of things. The first one is the sculpted detail. This has double importance since it also influences how the light affects the reflection on the skin. The rougher the detail, like in the cheek area, the less glossy the reflection will be. On other parts where we can find less detail, like the cartilage area in the ear or the nose, the reflection will be glossier.

The second important part is the reflection and glossiness of the skin, which is not only related to the sculpted detail but also to the oiliness of the skin. The forehead and nose areas are more glossy due to more skin oil concentrated in these parts. 

The last thing that makes skin believable is the color variation on the diffuse or albedo map. I like to do everything by hand, so I don’t use scan data on my personal projects. For the skin, I started with neutral skin color. After that, I picked one of the tiniest alphas in ZBrush, a very small dot. I set up the brush to Spray and under the properties of the standard brush, I turn down the color variation setting to 0.1. 

This gave me small variations of the color I had picked. That color variation is the key to painting skin. There are 3 regions on the face with slightly different tones. The forehead is more yellowish because of the bone contact. The cheeks and eyes are pinker due to more flesh and blood running in the area, and, in the case of men, the jaw area is slightly bluish due to the hair growing underneath. 

Painting in ZBrush also gives the advantage to paint in HD within the HD geometry, so the resolution is quite crazy. The other clear advantage is to paint and sculpt at the same time so you can give volume and paint little veins, moles, and pimples, for instance. 

The Hair

When it comes to hair, I still have a lot to learn to be able to give any lessons here. But I first use geo to block the hair volumes in ZBrush. This is very useful when it comes to achieving likenesses, for instance. It really helps to get the feel of the person you are trying to replicate. 

Then, in ZBrush, I sometimes use Fibermesh so that later I can export curves and have a strong base for my guides in Maya (I didn’t use Fibermesh for this project). Once in Maya, I use XGen. I used the legacy one for long hair characters and the interactive one for pretty much the rest.

It is very important to have the right number of guides to define a hairstyle. When it comes to beard or fur, the number of guides is not as crucial. I try to keep it as simple as possible and work with the guides first, sculpting them and shaping them the way I want, applying clumps next and noise afterward as modifiers. Sometimes, two different kinds of noise with different frequencies and amplitude are needed to get the desired result.

I added a sculpt attribute at the end to sculpt the hair itself this time. This way, you can create your flyaways and polish the whole thing, since you have full control of each hair individually.

The Skin Shader in Arnold

The SSS in Arnold is very easy to work with and it gives amazing results. I use the aiStandardSurface material with subsurface turned on to 1. I set it up to RandomWalk2, and then set up the scale. This value is usually between 0.3-0.34 in a real-life scale model of a human head. This value changes based on the size of your model.

The map that I paint in ZBrush is plugged into the subsurface color. The radius color is usually peachy more than red and I don’t map this attribute. For the glossiness of the skin, I have a map that makes the nose and forehead areas glossier than the rest. Nothing too fancy since I leave the sculpt done in ZBrush to break up the surface and also affect the reflection. 

For the tattoos, I used a duplicate of the skin and made it darker and a little bluish by using a Color Correction node. Then I used a layer shader where I had the original skin and on top I put the darker skin revealed by a mask that I made in Photoshop (to get the patterns) and polished in ZBrush afterward to finish up the map. This gave me more control and freedom over the look of the tattoos without having to include them on the albedo map.

Lighting & Final Touches

For the lighting, I start with different HDRI maps and played with them, at the same time I update the albedo and displacement maps from ZBrush. This way, you make sure your skin works under different lighting conditions. I rotate them and see what was a good fit for my model and what lighting worked better to reveal the forms and also add some mood to the scene and try to make it a little bit more interesting.

Once I've found something good with the HDRI map, I push it with some area lights (key, fill, and rim) and then decrease the intensity of the HDRI. For close-up portraits like this one, using area lights adds a little bit more mood.

As final retouches, I use Procreate on my iPad to add some Bloom to the image to help the lighting and also touch up the colors and the contrast very slightly to get the desired final look. 

Conclusion

My advice for future artists is first, you have to be passionate about what you do. That really makes the difference. And if character creation is your passion, then try to save some time for personal projects and practice as much as you can. You will never learn enough and there is always new technology coming up every year to improve your pipelines. Don’t forget traditional arts or other disciplines, like digital painting, it will make you a more complete artist. And always try to compare your work to the best out there to keep pushing yourself to reach that level, but don’t forget to also look back and see what you have achieved: seeing progress in your work will keep you going. 

Enrique Mateo-Sagasta, Senior Creature Modeler

Interview conducted by Arti Burton