Sinjin Treharne shared his experience of studying at Gnomon and talked about character 3D sculpting in ZBrush and texturing with Mari & Substance Painter.
I’m Sinjin Treharne and I grew up in Palo Alto, California. There weren’t very many programs for VFX at my school, so I used online resources to learn. I started using programs like Maya, Mudbox, and Blender when I was in high school to learn about the process of modeling and texturing. From there, I went to college for Production for Film/TV but it was not what I really wanted to do. Eventually, after almost a year, I decided to go to Gnomon.
I took Gnomon’s 2-year modeling and texturing track and I can say it is the best educational experience I’ve ever had. Gnomon gave me all the resources for learning how to work within a professional pipeline. The resources that they provide are incredible and the teachers are very knowledgeable about studios and the processes they use to complete a project. So far I have not worked on any industry projects, only personal and school projects, but I cannot wait to enter the industry.
Studying Concepts & Sculpting
The first thing I try to look at in the concepts I have chosen is how the artist uses light and shadow to communicate anatomy. I then look for real world reference of similar faces to use for comparison – it is better to use a single face as a reference and then deviate from it. After this, I try to find additional real-world references for the costumes and props of the character. For example, in my Giants project, I used historical references from the Metropolitan Museum’s online collection to look at different types of shields that the Giants may have scavenged for as materials after a battle. I try to keep my anatomy and pose feeling natural for a character/animal as I believe that is an important part of making a believable character. I also look up to other artists to get inspiration for how a character is going to be communicated in 3d. Some of the artists I look up to and try to follow for reference include Raf Grassetti, Frank Tzeng, Igor Catto, Vimal Kerketta, Rino Ishak Zvizdic, Rodion Vaslov and many more.
The more I observe these artists, the more I have tried to include a ‘from scratch’ mentality in my work – meaning you create everything from the character sculpt in ZBrush (creating the clothes and props by using extractions, Zmodeler, etc). This allows me great freedom to visualize the subject and see how each element fits with the character. I like using ZBrush to sculpt, as is it is a great tool for making high-quality assets and getting material detail in my sculptures. When I start sculpting, I look for anatomical landmarks where the muscle attachments happen and the shadows that the overlying muscles create. I always try to keep in mind that the skeletal/bone structure is really what makes the character/creature anatomy convincing. This is especially true for human faces, as it is much easier for me to see what I’m sculpting by looking at the shape/position of the cheekbones, orbital bones, brow, and jaw.
For clothes and costuming, I use Zmodeler to create clean bases in ZBrush, which I then use to construct clothes with panels to mimic clothing in real life. I have also used Marvelous for some clean bases, but generally, prefer to sculpt clothing in ZBrush. My reason for this is that you will usually have to sculpt on top of simulations out of marvelous to get good results anyway and by learning to create clean bases in ZBrush, it helps to simplify the process. It is much easier to pull the cloth where you want/art direct how it looks and lays on top of the other forms while in ZBrush, especially when fine-tuning a pose. I repeat this process with accessories – using Zmodeler in ZBrush to make a base to sculpt on. For more hard surface assets I like to stay in Maya and include small sculptural details later on in ZBrush. The final, but most important thing to do, is just making sure that every part of the model is sculpted. It is a detail-oriented process – making sure that each wrinkle, fold, surface or edge has been sculpted over and given its own details.
For the texturing process, my main tools are Mari and Substance Painter. For the skin painting, I typically take a decimated version of my sculpt with UVs into Mari and use the Texturing XYZ displacements to add fine pore and wrinkle detail. I start by combining all the different channels in Photoshop and cropping the textures of the forehead, nose, and face. I also like to create a tileable texture to blend between the transitions in the skin. I paint around the corresponding areas of the face from different angles and use masking to blend between layers in Mari and make sure there are no seams or breaks in the transitions between different types of skin.
For the diffuse map, I start out by finding a good texture/photograph sample for skin and make a seamless texture out of it, which you can tile inside Mari for a base layer. From there, I use baked curvature, ambient occlusion and thickness maps from Substance Painter to layer with blend modes on top of my tiled diffuse. I use my decimated mesh (with UVs) from ZBrush and bake the mesh maps in Substance Painter as it helps to create dirt and masks for different tones in the skin along crease lines. From then on I paint the different tones of the skin: gray to blue-ish tones around the eyes and jaw, red around the cheeks, nose, ears, and the yellower areas around the bridge of the nose, brow, and jaw. Of course, depending on who your subject is and their complexion, these colors can change greatly. It is best to just research your color palette thoroughly. Finally, to add freckles, sun damage, liver spots, capillaries, scratches, and scars, you can experiment using the procedural noise and oil patterns in Mari to create interesting natural looking variations in skin. By overlaying and using masking, you can paint in variation around certain areas while keeping other areas more neutral. Then, in the end, I overlay the Texturing XYZ red channels and green channels by using a copy channel layer in Mari to get color/dirt into the fine pores and wrinkles. This adds a very realistic touch to the color of the skin and really helps bring out detail in the painted displacements as well.
The last part is painting the skin roughness maps. You can potentially have one or two roughness maps to get very fine specular information in the skin shader. I use the Texturing XYZ maps and the Copy Channel node to use the red and green channels for the fine pores. Then I just paint on a layer underneath so that the details of the XYZ maps stay intact. I paint the roughness accordingly to the oilier/wetter areas of the face by approximating the values I want in Maya. Keep in mind that the more accurate your lighting is, the more time you can spend actually painting the skin maps. This is why I use my own Light Rig with HDRs from different times of day and positions of the sun in the sky.
I would say one of the most important lessons I learned at Gnomon, was to look at scans of real people as it really helps to cement knowledge of anatomy and sculpting to real life. Second would be to never stop studying anatomy. Anatomy can change drastically even from person to person so you could spend your whole life studying just human anatomy and still learn more. That is what provides the viewer with a sense of realism and soul. In each person, animal, creature, etc. the forms should be unique and different as this is what makes it beautiful.