Making a Scull Warrior in ZBrush & Marmoset Toolbag

Introduction

Hi, my name is Daniele Colombo, I’m a self-taught artist and I’m currently working as a freelance 3D Character Artist. I had a programming background and worked in the video game industry as a graphic/engine programmer on titles like Sackboy a Big Adventure, Forza Motorsport, and others for companies like Ubisoft and Sumo Digital. I then decided to change my career path and focus on character creation. I’ve learned everything I know via online courses from anatomy through the most relevant software. I personally think we are very fortunate in this day and age because we can choose to learn and keep learning from the best in the field without even leaving our desks.

Design Choices and References

My latest piece, Skull Lord, is based on the amazing art piece by Stepan Alekseev. I was immediately captured by his style and by that particular piece too. For personal projects, I’m always drawn to art that “speaks to me”, in which I can see a story: just looking at the armor I imagined the character was forced through a ritual and that drove all my design decisions. I gave his face some soft parts and more human-looking eyes to let him “speak” his thoughts to the viewer, in that way, I hoped, it was easier to see beyond his condition.

References are super important, especially when you have to translate a 2D concept that makes heavy use of brush strokes to convey an idea without fully realizing it. 3D has different rules, the most strict of them is clarity, you have to fully realize your forms, and that’s where references are very helpful. Like many, I use PureRef to organize my references board and group the images based on materials, colors, forms, subjects, and moods. In my references, I also find it very useful to put a black and white, and mirrored version of the original concept along with other artists’ characters I use as a quality target.

Sculpting the Head

Approaching the head was quite challenging since what I had in mind was to slightly change it but retain the overall original structure, I first identified the features to retain to make justice to the concept art. For me, those were the main shape of the horns, the spikes, the zygomatic bone, the frontal bone/eyebrow area, and the chin shape. The rest of the face was more or less open to interpretation.

I started with the DynaMesh SubTool and mainly used ClayBuildup with alpha off for a softer result. Move and DamStandard brushes were used to layout the main forms. I always try to keep the DynaMesh resolution as low as possible and up-res it only when it can’t retain the forms. In the first passes the head was very clean, the main rules are working on the big shapes, proportions, and blockouts, leaving the detailing for later. At this stage I split the head into 4 different parts to make the sculpting process easier: the horns, upper skull, jaw, and soft parts of the head were divided into different SubTools. Keeping them separated allows you to freely move and change the proportions of one piece without accidentally affect another, or using x-mirroring for a longer time on a subset of those SubTools. You can be quite free in the way you split a mesh in ZBrush since the process to fuse the pieces back together is almost pain-free, you can use DynaMesh or the new operators like "Remesh By Union" with some Smooth plus Sculptris Pro touch-ups. That’s the reason why I keep splitting pieces if I feel I need to.

When I felt all the different headpieces were solid enough I fused them back in a single mesh, except for those SubTools that are clearly a separate part, like teeth, the soft part of the head, and the eyes.

Even though I don’t use colors while sculpting, I’m an advocate of shades of gray to visually separate the pieces while the sculpt is taking form. You can see I visually diversify the soft parts from the hard parts of the head with a gray shade, which helps my brain to focus on how I should treat a certain part of the mesh. Speaking about the colors, the only use I made of them in the early stages is to give a character a fake iris, the way an eye looks can drastically change the mood of the entire piece.

The skull spikes were done using Sculptris Pro plus Snake Hook to build the forms and Trim Dynamic with the hPolish brush to finalize them. While for the overall skull you can study real references to understand the material language like the shape of ridges and crevices, the horns had a very fantasy look. The challenging part was to make them believable. For doing so I’ve incorporated different real word shape languages that could support the design: you can spot the characteristic ridge of a goat’s horn near the “ear” of the monster, or get inspired by other forms of nature, as an example, I’ve used the tree roots as a shape language where the horns and the spikes join the skull. I particularly like those because they support the idea of a curse grown onto/from him, strengthening the underlying message. All of those forms were created using a very small group of brushes, I mainly use ten brushes for all my projects: ClayBuildUp (without alpha), Move, SmoothStronger, DamStandard, Standard, Zmodeler, hPolish, Planar, Clay and Inflate.

For the soft parts of the head I’ve studied animals with a heavy skin, like elephants, and very old people, I used the DamStandard and Standard brush to create the main big wrinkles. When a pattern repeats itself quite often I also use the Xtractor brushes to capture and reuse it to speed up the process, for example, 80% of the big wrinkles on the neck were done via the Xtractor brush using a “copy” of the face pattern and then adjusted manually using the common brushes.

The fine details of the skull were done using a combination of alphas on the Standard brush and Surface Noise. Most of the alpha I used for the skull were black and white images of old and scratchy walls dropped randomly on the surface and then adjust or enhanced manually. When doing detail work I always use the layer system in ZBrush and split different patterns/details into different layers so that I can use the layer system as a mixer to balance them based on the overall presentation.

Sculpting the Armor

Like with the head, I slightly changed the design of the armor but kept what I felt were the primary details intact: the breastplate and the gorget were almost unchanged. The rest of the armor in the concept was depicted as a leathery material and that had its own challenges: I was trying to make this fantasy creature believable, the more I could draw from reality and common historical knowledge the better grounded it would feel. So I gave my character a gambeson and almost full plate armor, with a chain mail, pauldrons, and gauntlets.

The breastplate was the most challenging part of the entire armor, I’ve started with the creation of the round-shaped plate, then I duplicated the piece, inflated the duplicate with a negative value to bury it under the surface, I start sculpting the embossed figures on the buried duplicate using DynaMesh and Sculptris Pro, making only those details popping out from the surface of the original plate. Once those embossed shapes were good enough I’ve split them into separate SubTools: the human figure, the six observer, the three doors, the ritual cloth, and other details were all split into different pieces, that granted me the ability to reposition or modify each of them without ruining the others.

Creating embossed figures can be very tricky since they need to describe volumes and direction even when they are pretty flat, to ease the process, I’ve resculpted some of them as normal 3D pieces with full 3D volumes and then used the Gizmo to scale along a direction to flatten them, as an example, the six observers and the upper part of the crucified figure were done like this.

After all the embossed pieces were finalized I merge them back to the breastplate. Some of the repeating “rope” patterns or surface damaged were done once with normal brushes and then captured with the Xtractor brush to be used on other parts of the armor.

The most important thing while creating parts of the armor, like the gauntlets or the pauldrons, was to rely on very good historical references on which you can build your fantasy interpretation, for that I’ve browsed the beautiful catalog of the Metropolitan Museum, where you can find high-res images of armor in their amazing collection.

The chainmail was easily done with ZBrush NanoMesh, I’ve created a couple of rings intertwined and angled in a specific way such that, when repeating, they’ll intersect with one another. Once the two rings were ready I’ve used a very low-res version of the underlying gambeson as the guide-mesh and repeated the rings all over it. As the alignment was important for the rings to intersect correctly, I’ve chosen the one that was the most consistent and then fixed the few spots where the links were not oriented correctly using the Zmodeler “Spin Edges” onto the incriminated quads of the guide-mesh.

After the character was posed I used the Standard brush to deform the guide-mesh to create the compression folds and simulate the gravity pull on the chain mail and finished it up by manually fixing the position of some rings. Even if similar in shape, the stitches of some leather parts were done using a custom insert brush.

Topology and UVs

Super clean topology and UVs weren’t the focus of this piece but were required to bring the character inside other software like Substance Painter, my retopology workflow is a mix of automatic tools and manual work. I usually try Zremesher first on each SubTool, if it’s not good enough I try to better inform the algorithm using ZbrushRemeshGuides brush or Polygroups with the corresponding flag turned on in the Zremesh panel, if it’s still not good enough I move on a more manual stage in Blender, fixing the bad topology but reusing most of it, or in extreme cases by doing it all from scratch always in Blender. For example, simple shapes like the dagger, the forget, and some plates were changed using Zremesher, the head and the breastplate were a mix of automatic and manual while the cloth under the belt, the straps, and some plates were done from scratch. To create the UVs I used Blender since it has some solid tools and techniques, even though some of them aren’t well known, if you don’t know many of them, I always suggest the amazing tutorial by Daniel Bystedt.

Texturing

All the texture work was done in Substance Painter. Before starting to paint I always set up my scenes with the Tomoco Studio as the Environment, turn shadows on, setting the color profile as sRGBf and the shader quality to 64spp. I find these settings to be the ones that bring the most consistent results.

The metal material used for the entire armor was developed when texturing the breastplate, making believable materials is quite hard and references are key, besides that, since I was planning to render my character with a ray-tracer, I knew I couldn’t rely too much on the real-time viewport, thus I kept switching to the Iray view to check the results. This ability to switch easily between the two modes was essential. I tried to replicate the material of a real Italian medieval helmet, later I added exaggerated details to make it pop a little more.

I usually work my way up while creating materials, I always start with a base fill layer with a fill effect to give it a darkening color variance, I then add very subtle colors variations in the red, green, and yellow tones using masks, to break the monotony of the main color, then I concentrate on the high values, using noise to create interesting details like scratches or tool marks. I then try to give interesting effects on the edges or crevices like wear or oxidation, finishing it up with a bunch of variations in the roughness. On top of all of that, I always use a paint layer set to pass-trough with a sharpen effect to apply the sharpen globally and a very subtle layer that directly mixes the cavity map with the color to make the final result pop a bit.

All the layers make extensive use of generators, grunge maps, procedural maps, and baked maps. I’ve baked all the character maps inside Marmoset Toolbag, I think the baking tools that the software has are unmatched at the moment, especially the ability to see and modify the projection cage in real-time.

The big difference between texturing the “non-living materials” versus the head of the character was how manual work I put in the creation of the colors or the masks for the layers. For example, it is easy to dictate where dirt or wearing should appear on the metals or leather, based on a baked map but isn’t so automatic to dictate where a vein should appear or where the skin should be more yellow due to a near-to-the-surface bone.

For non-living materials I mainly use automatic processes like Smart Mask, generators, etc. with some manual touch-ups, meanwhile, for the others, it’s the reverse. In any case, what you need are very good and hi-res images for reference; texture.com is a great place to buy some of those.

The fur was the only thing I painted in ZBrush. In order to give it a convincing color variation I used a tree bark texture and projected it onto the leather cape via the Spotlight Projection feature, then blurred the result with the Smooth brush and used FiberMesh to grow the fur from the cape by inheriting the underneath color.

To easily create the tufts, I used this Custom Grooming Brush Kit made by Pablo Munoz. In it there is a very handy brush called the “breaker” that let you quickly assign new Polygroups to the fibers, it was super easy to create new Polygroups on the fly and then, with Polygroup Masking on, concentrate my grooming strokes without affecting the other fibers around the area.

Rendering and Final Touch-Ups

The character was rendered using Maverick Indie, it’s quite new and is positioning itself as a competitor for Keyshot. The lighting setup for the main shot was a three-point light solution, with an HDRI as the fill light. The key light was coming almost from the top, another from the left of the image, and the last one was a simple rim-light to separate the character from the background. Maverick is very easy to use and has some very smart features that help a lot while testing your lighting or shading, like the ability to position lights by clicking on the surface of the character, an easy to use history system to compare different result, a very good denoiser, or a powerful light mixer that enables you to change the attributes of a light and see the result affecting an already completed render without doing any additional computation.

After the rendering was complete I’ve done some post-processing in Photoshop, I mainly adjusted the contrast and color balance, add a backplate, and some dust FX for some of those shots.

Final Thoughts

This project was quite challenging for me, especially the act of balance between the original concept and a somewhat realistic depiction of it, on that note, the materials were redone twice before I hit the quality bar I set for myself after seeing the amazing piece Stinky's Long Journey by Rodion Vlasov, that fantastic troll really pushed me to make my Skull Lord way better.

If I had to give a piece of advice to a beginning Character Artist I would say: always look for feedback on your work, this piece had a ton of it during its development, you’d be surprised how much better this piece became thanks to all those critiques.

If you want to be part of my new journey on social media you can follow me on Artstation, Instagram, or Twitter.

Daniele Colombo, 3D Character Artist

Interview conducted by Arti Sergeev