Studying Organic Character Art: Anatomy & Skin

Troll: Start of the Work

The Troll character has been a fantastic project to work on. I started sculpting it back in February 2019 but had to put it on hold because of school and work. I knew I wanted to get back to it, and I’m happy that I did. The key reference I have been using is the awesome concept art made by Sandra Duchiewicz for Warhammer: Total War. I wanted to go for a bit more realistic and toned-down look for my version of the character which made me do a few design changes, mostly on the head, making it more orc-ish. 

I created a moodboard and reference sheet in PureRef of what I thought might come in handy when I started sculpting and then added some throughout the project. I also valued getting examples of the game characters already translated to 3D in the game. 

Here are some of my key references (not all ref included):

Mouth

Creating the mouth was a blast and creating the tongue and playing around with subsurface scattering in Marmoset was a thrill. First of all, I created a scatter map in Substance Painter simply by painting in white with what I wanted to be affected by scattering and black for what I wanted to leave out. Then in Marmoset, I set the diffusion to subsurface scatter and chose the scatter depth and translucency. In simple terms, scatter depth controls the waxiness of the material and translucency controls how far the light penetrates the surface. The settings of these parameters depend heavily on the scene scale (to get an understanding of your scene scale, go to the render panel and enable “show scale reference” ). Just play around with the settings until you find something you like. Keep in mind that adding subsurface scattering will soften your normal details.

For the color information on the tongue, I did all the painting in Substance Painter. For the base color, I like to start dark with a dark color, and then work up with lights and hue variation. I recommend using the dirt brushes in Substance Painter, they have a nice texture for organic materials in my opinion.

Texturing Skin

Working on the details, I wanted to do most of the high-frequency details in Substance Painter. This provides multiple benefits. First of all, it’s non-destructive, meaning you have the option to do major changes and experiment on your model without consequences. In ZBrush, you would have to re-bake your maps if you wish to make changes. For this project, I used Substance Source as a base for the pore details. They have a lot of organic materials on their website which I recommend checking out.  I painted in the different materials on different fill layers, then blended them together to create natural transitions (use reference during this phase!). I tick off the color and roughness information because I like doing those maps separately. 

When creating scars across the body, I wanted them to be subtle. When layering this in Substance Painter, I always use fill layers with masks. For me, using fill layers is a must, because being able to change your diffuse, roughness and height at any point is incredibly powerful. Building up the scars was pretty simple. I started with the redness, then just kept looking at reference and deciphering how the scars are built up. Having some negative height in addition to the color is great to increase the detail on the character. I recommend using a rough brush, like the artistic brush or artistic heavy (native in Painter). Cut with a simple basic hard brush, then add some specularity variation to the wound with the roughness set low, and at the end add dark marks to illustrate dried blood spots. Now you have some combat wounds! 

When working on the skin, I learned a lot from watching Magdalena Dadela. She has multiple videos you can find on Youtube. In practice, I did the diffuse similarly to the way I built up the tongue, just a lot more layers but still painting with a simple dirt brush. A tip is to use your baked curve map to add redness to your cavities. Use references when doing this, there is a lot of color variation, especially in the face, be sure to capture the nuances.

Building up layers of dirt is always a treat. This is your chance to tell a story with your character. Where has he been, where is he now, etc. This is what will make your character seem grounded in a real-world environment. I usually start my dirt base with a generator based on my position map, then add more layers painting in variation by hand. Be sure to paint your dirt with a different roughness value than your skin. If you leave it the same, it will look like discoloration on your skin (unless that is what you want).

Retopology

For this project, I wanted to have quality rather than optimization. That being said, everything is hand-retopologized in Maya. The most important part of retopologizing is to capture the silhouette with as few polygons as possible. Other things I did for optimization was saving UV space with duplicates and mirrored geometry. When duplicating, it is important to randomize the orientation and angles to avoid repetition. When mirroring geometry, move the UV shell one unit to the right (or any direction). When you bake it in Marmoset, it will bake the mirrored geometry too. I did this with the fingernails and ropes on the shoulder.

Presentation

Presentation is not my favorite part.  I love film noir lighting which often has this foggy mystique feeling to it, and I wanted to capture that in the presentation shot. Working in real-time really makes the process a lot more fun and easier to experiment with. This is the light setup for the scene: 

On my keylight, I set a lower distance, so that I’d have a light falloff. I set a narrow spot angle, so the tree trunks going out from the troll's trapezius wouldn’t catch the light. Then, I also added spot vignette and turned down the spot sharpness, so the light had a softer falloff. 

I also added a fog actor in Marmoset Toolbag and kept the falloff on exponential. You can also change the color but for this project, I kept it white/grey. 

Apart from lighting, posing your character is an important part of your presentation. It appears more lifelike and adds a lot of character even through a simple and subtle pose. My initial plan was not to pose the character, but my girlfriend encouraged me to take the extra time to do it and am grateful for it.

Afterword

Finally, I'd like to thank my friend and teacher Oliver Barazza who sent me invaluable feedback during the project, as well as Donpolygon and Glaucolonghi discords. Without them, I wouldn't be able to get the same result.

Thanks for reading!

Bjørnar Aarset, Character Artist

Interview conducted by Kirill Tokarev