Making a Realistic Horse in ZBrush, Substance 3D Painter & Marmoset Toolbag

Introduction

Hello! My name is Adarsh, I am a Character and Prop Artist from the UK. I like creating game-ready characters, creatures, and props that further the narrative, weaving together a tale of visual storytelling. I received my master’s degree in Game Art from Sheffield Hallam University. I have a bachelor’s degree in Mechanical Engineering and four years of experience as a product designer in India. Although engineering introduced me to the field of 3D, which I am immensely grateful for; I believe it lacked the essence of creative freedom. All the constraints factoring into the creation of tangible objects felt restrictive. 

Art has always been my one true love. I have been practicing traditional art almost all my life with mediums like oil on canvas, watercolor, charcoal, oil pastels graphite, etc. Ever since I was little, art and colors have come naturally to me. Creating fantasy worlds and designing fictional characters gave me a sense of fulfillment. It was what drew me to computer games. Seeing the result of the effort of artists that went into the making of the games inspired my curiosity to learn. So I decided to give game art a fair shot. My experience with design, love for art, and passion for games led me through this journey of true self-discovery. 

My background and experience immensely helped me in learning and acquiring the necessary skills required for game asset development. Working on my university projects has been a steep learning curve for me. They introduced me to several software tools, like Blender, Maya, ZBrush, Substance 3D Painter, Marmoset Toolbag, and Unreal Engine, and helped me understand industry-standard software workflows, game assets, character, and creature creation pipelines. 

One such key project, my first attempt at character and game asset development, is called Mercury. Project Mercury was something I created for my first trimester in the MA Game Art program. I conceptualized a character called Mercury with a series of artifacts fitting a steampunk theme. The narrative of Mercury follows him, an explorer and inventor, who resides in a world within the realm of the clouds. On one of his expeditions, he accidentally discovers a world outside of his own and calls it ‘The Surface’. On his preliminary explorations, he gathers that the atmosphere on the surface is un-ionized and filled with the brightness of daylight unlike the ones in his world. To adapt better to this new world, Mercury builds a series of devices. Two such devices are called the “Lightening Conductor” and the “Day Vision Goggles”. The software workflow I used for this project was Blender-Substance 3D Painter-Marmoset Toolbag.

The next project that introduced me to the Maya-ZBrush-Maya-Substance 3D Painter-Marmoset Toolbag-Unreal Engine workflow is called “A Cyber Surgery”. This sci-fi-themed group project revolved around the aesthetic of an underground illegal cybernetic surgery/lab. This project is loosely based on the concept by Ian Llanas’s Cyber Surgery. My contribution to this project was the concept setup, assets – the chair, the surgery bed, the IV stand, and the cryo chambers – display HUDs and UI, the Unreal Engine 4 level, the material, the material instance, and the shader setup.

For my master’s project, with all the skills accumulated and new tools explored, I decided to build upon the Mercury project. To create an all-encompassing narrative, I made another character from the universe – Mercury’s trusted travel companion called Oasis.

In this article, I will be showcasing the creation of Oasis, the accessories that go on him, the techniques that I learned to get me there, the challenges I faced, and the methods of optimization I used to overcome these problems.

The Oasis Project

I like creating concepts and building narratives before diving into the 3D pipeline. This helps embed the narrative into the creation workflow. When I first created the concept of Oasis, it was called the Equine Ornithopter – Oasis, one of the biggest pieces from the universe of Mercury. Oasis, the horse, is the name of Mercury’s trusted companion. Equipped with a steampunk Ornithopter (winged armature), one of Mercury’s inventions, Oasis transforms into a cruiser chariot for Mercury’s aerial voyages.

Exciting as it was, the idea was unrealistic to execute from a timeline point of view. So, I decided to limit the concept to a more practical and executable design. I replaced the ornithopter with a series of assets: a hat, a lantern, a water canteen, and a rope bundle. 

Since the ornithopter had the potential to be a separate project in itself, I spent more time learning the skills required for hair card creation, advanced organic texturing, and realistic asset creation workflows. These skills are essential in the creation of character and creature art, and as an aspiring character artist, I was very keen on improving my skillset. Since I had a contingency prepared from the concepting stage, I designed the horse with the saddle kit and the ornithopter as separate elements. The concept provided a concrete foundation to build upon.

The perfect start to any character project is having an in-depth understanding of the subject's anatomy. I realized how nuanced the knowledge of equine anatomy is when I needed it during the concepting phase. Hence, I invested a substantial amount of time in gathering references of horses of similar form, creating a library of horse skeletal anatomy, musculature, skin shades, fur propagation, hide, hair, hoof textures, and eye textures, and for color composition. There were references from various in-game models for popular games like The Last of Us 2, Red Dead Redemption 2, and other game-ready horses from ArtStation. This in-depth study helped me bring about realism to the concept along with the sculpts and textures. I narrowed the horse reference down to one thoroughbred racehorse called Daddy Long Legs with prominent features like chestnut hide, white ankle stockings, golden brown hair, and brown-and-white fur patches.

The first inspiration was drawn from the horses in the popular game The Last of Us designed by Priya Johal. 

References

One of the challenges I faced while creating original designs was the lack of composite tutorials and production documents for the elements involved in my project. After exploring several avenues, I landed on broaching the subject by studying horse anatomy. Luckily, I came across websites outlining all aspects of equine physiology and anatomy. One website that was especially helpful was catering to horse equipment and health called Equishop.

The website described horse musculature and skeletal proportions in detail. The labeled horse anatomy diagrams provided a reference to accurately position the muscle groups and bony landmarks for the eventual sculpting phase of production.

The hoof of a horse is a complex part of the design as it adds a touch of realism and provides personality to the character. I paid special attention to the design by referring to a horse health website for the hoof anatomy and reference images. 

A vital piece that brought the whole picture together was a website run by Leah Koerper called Shoestring Stable. This website is dedicated to DIY-style miniature horse modelling. Shoestring Stable was a treasure trove of vital information I needed to accurately design all elements. Since the website has artistic origins, the author was meticulous in putting together multiple close-up images of various horse body parts. Images of musculature and skeletal anatomy were available from all views. The information on fur coats and hair growth patterns was also pictorially captured. This helped me realistically texture the fur coat into the material maps. It was a great jumping-off point to get accurate proportions and skin texture patterns for the final model.

I closely referred to a thoroughbred racehorse owned by Michael Tabor, Derrick Smith, and John Magnier called Daddy Long Legs. The stallion was the closest in physique and chestnut coat to my original concept. 

ArtStation was a great source of research on 3D models and renders of horse anatomy. One such example of an accurate 3D model of equine anatomy was by Farzin Izadyar. 

Another reference was by Dmitrii Prosov.

A great reference for the finished product including the additional elements of the saddle pack, reins, stirrups, and harness was designed by Pogar Marius as part of an asset pack.

After compiling all the available information, I created a base mesh of Oasis in ZBrush. The anatomy skills came in handy to bring the base mesh to the appropriate shape, size, and form. 

Modelling & Hair

I built the sculpt of Oasis up from a sphere and added skeletal details, musculature, skinfolds, and veins layer by layer. To that, details like pores and cracks on the face, scratches and cracks on hooves, and primary fur coat were added onto the body. 

Next, I focused on the eyes. The general process of creating eyes is to use a flat texture for the iris and sclera, make height maps using the texture in ZBrush for high poly, and then bake it over the low poly model. Unfortunately, the eye textures for horses were not readily available, so I resorted to sculpting the iris in the high poly model manually, referring to close-up references of horse eyes in ZBrush. 

A distinguishing feature of a horse eye is the nictitating membrane, or the third eyelid, which I modelled in ZBrush. Following this, I created the equivalent low poly models of the entire eye in Maya.

For realistic hair creation, I referred to several resources. One that was particularly useful was "Female Bust Course in Marmoset Toolbag" by David Zavala. Using ZBrush’s FiberMesh, I created 6 different hair patterns with variations in density and flow and arranged them in a 4K square black background render view to fit into the UV space of the hair cards that I created in Maya. 

I then placed a combination of these cards with varying sizes on the horse head, neck, and tail in ZBrush and refined it using a Move Topology brush. I also gave the arranged cards a gravity simulation inside Dynamics using the horse body as the collision object.

Back in Maya, I moved the cards using soft selection and then smoothed the edges. In Photoshop, I created the normal map for the hair and a simple gradient which acted as normal and albedo while I was texturing hair.

Accessories

With the gathered references and design modifications, I finalized the list of accessories as a face harness, reins and belts, a saddle, stirrups, satchels, duffle bags, a luggage bag, a hat, a water canteen, a rope bundle, and a lantern. From the references, it was evident that most of the assets that go on the horse are either leather, cloth, or metal. I decided to progress with a combination of these textures with a realistic colour composition. 

On the back of the horse lies the saddle with hanging stirrups. The leather on the saddle has features like embroidery, threadwork, jewelry buttons, etc. Additionally, there is a chesterfield pattern for the rest cushion. Placed on the rear back of the horse is a luggage kit containing two satchels, two duffle bags, and one big luggage. The highlighting features of the luggage kit are large sheets of leather, embroidery, metallic emblems, and belts.

The ideas for the harness, reins, and belts are straightforward, a combination of worn leather and metal. As a part of the contingency assets, the significant feature of the hat is a fabric braid and a metal emblem. Other contingency assets are a jute rope bundle, an old lantern, and a jute fabric bag canteen. The assets tailor the narrative of a traveler armed with essentials. The crux of the project is to convey utility, usage, and wear through the assets.

I modelled the base mesh for assets like the hat, the saddle lantern, and the canteen in Maya using hard-surface modelling techniques. The lantern was the only asset where I reused the base mesh as low poly for baking. Since the majority of the assets were organic, I had to find creative ways to retopologize. As fitting these assets on the horse involves a variety of deformations that cannot be accounted for in the base mesh creation stage, requiring a post high poly treatment.

For assets like belts, reins, harnesses, and ropes, I used the sweep curve feature with respective cross sections suited for the design. For the rope, I wound multiple cross-sections in the form of a helix to achieve a realistic rope. The same guides were used to create a cylindrical low poly which I carried to ZBrush to retain the deformation. I manually arranged the curves to manufacture the randomness in all these assets. The design of many of the assets had some semblance of symmetry and hence I relied on the mirror function of ZBrush. The advantage of creating assets on a giant quadruped is that both sides can never be viewed simultaneously. This implies that I need only unwrap and texture one-half of the assets. For embroidery on leather, stitches, and the braid on the hat I created various IMM brush instances in ZBrush and used the curve function to run it across the desired path. 

The majority of the low poly was created using quad draw. Features like embroidery, stitches, and other details were baked from high poly. I removed the back faces on several assets which were more likely to be always hidden to save the poly count. Holes on models with no back faces were directly introduced using opacity maps in the texturing phase. 

Unwrapping

For the horse, using a slightly lower subdivision level, I created a low poly retopology using a combination of ZRemesher in ZBrush and Quad Draw in Maya. Using ZRemesher guides, I manipulated the flow of new topology.

I added loops around the eyes, nostrils, mouth, ears, and propagation edge loops along the length of the limbs, neck, and torso to make the horse suitable for rigging in Maya. The poly count for the low poly is 9396 polys.

I added seams on the horse around the neck, ears, limbs, tail, and hoof edges and one along the length to open up the UVs. I then unwrapped the UVs along the seams and arranged them proportionately in a 0 to 1 UV space.

For the assets, however, I relied completely on the use of Quad Draw. I imported a relatively lower subdivision model into Maya and created a fresh topology using the high poly as a live surface. My approach to unwrapping and texturing low poly assets was to treat each asset as a hero prop and therefore assign a UV and texture space for each of them. Here is how I combined models into assets sharing UV space:

After smoothing the edges, cleaning up the mesh, and matching vertex normals to face normals, I moved on to texturing. 

Texturing

One of the main challenges I faced while texturing the horse was finding a tutorial to guide me in the right direction. I found tutorials on human skin texturing in abundance but none elaborating on fur texture creation for animals for the quality I intended. This led me to experiment a lot. In the pre-production phase of the project, I experimented with horse hide textures using Substance 3D Painter. This practice really helped me pull off details like fur, roughness variation, colour composition, and anisotropic specularity in the production phase.

As I was aiming for realism, it was really important to get the fur and eye textures to the maximum quality so that when they interacted with light, they appeared believable. I started off by baking high poly texture maps onto low poly in Substance 3D Painter. 

With that, I stacked up layers following the steps outlined below:

1. Rough base skin with dark patches around skin folds and light patches around exposed areas.

2. Using curvature and ambient occlusion from the sculpted fur layer to give a little bit of shine to break the base skin roughness.

3. Painting micro fur details in Substance 3D Painter on top of the sculpted fur to enhance the effect slightly. I created alphas from close-up fur images and with a combination of brush and stencil and then painted on the first layer.

4. Using this method, I created two fur layers, one following the fur growth direction closely and the other very sparse in random directions to give the natural fuzzy feel. I gave a very contrasting shine to these fur layers to make them stand out from the rough base and to also break the anisotropy that I was planning on introducing in Marmoset Toolbag later.

5. To give these fur layers a bit of depth, I used anchor points to introduce ambient occlusion to the painted layers.

6. I provided varying colour values to bring about the chestnut effect and a contrasting light colour value to the topmost sparse fur for highlighting.

7. To give the hide a bit of character, I introduced features like white ‘ankle stocking’ fur, white fur patches on the face and torso along with moles on the body.

8. For hooves, I created a dull shiny wood-like material with mud and grime with subsurface scattering using a thickness map to derive the keratin-like effect.

To make the eyes, I baked the high poly eye sculpts onto the low poly in Substance 3D Painter. The sclera, Iris, and pupil were one mesh while the cornea was another with a nictitating membrane as the outermost layer. I added transparency to the nictitating membrane and cornea. Textures of the iris and blood vessels were painted on the sclera using Photoshop, Substance 3D Painter, and reference images. I added a veiny normal map to the cornea for a bumpy feel instead of a glass ball effect. 

For the hair, I used the alpha from the ZBrush FiberMesh render and then generated the normal map in Photoshop. Using the same alpha, a height map in Photoshop for ambient occlusion mask was created. For albedo, I used a desaturated gradient mask and added the colour in Marmoset Toolbag. Finally, anisotropy, gloss, specularity, and transparency over the alpha will be given.

The primary materials of the accessories were leather, metal, jute, and cloth materials. The most invaluable trick that I learned for the realistic treatment of props is to give them sufficient roughness breakdown.

For the albedo, I built layers. The base layer had minimum details and basic colour and roughness information. Then I added layers that gave texture to the asset, like cracks and scratches on leather, an intermediate paint layer on metal, a fabric pattern for the cloth, and a jute fibrous pattern for the rags. High-quality reference images were used to paint on these intermediate layers after combining them in Photoshop.

Topping these layers, details like deformation, scratches, wear, grunge, dirt, etc., were added. I utilized curvature and ambient occlusion texture maps to bring about these effects using masks and generators. I broke the procedural effect by adding masks and painting. Embroidery effects and threadwork on leather and emboss on metal and jewelry were baked down from high poly. To ensure the assets stood out while also not undermining the horse textures, I had to work on colour composition by taking trial renders.

Rendering

With the textures ready and several testing of the textures in Marmoset Toolbag, I moved on to rendering the assembly using the tool with ray tracing, ambient occlusion, shadows, reflections, and post-processing effects such as slight amounts of vignette, bloom, and contrast enabled. 

For tone mapping, a handy trick I gathered was to use ACES as this closely resembles a real-time game engine tone mapping. It is also essential to use similar tone mapping display settings in Substance 3D Painter as well to get the final rendered results as close as the created textures. I used a free ACES add-on for Substance Painter on Gumroad by Brian Leleux, which modifies the tone mapping to match ACES Unreal Engine 4 colour profile. This helped me create textures with more realistic visualization of the output.

The low poly assembly was imported into Marmoset Toolbag after manipulating the limbs to create a standing pose in Maya. With a basic lighting setup, I created the materials for each asset. For the horse, to give the fur coat a realistic shiny yet rough effect, I introduced anisotropy using a flow map.

Anisotropy without flow maps tends to reveal the UV seams in the mesh. An interesting insight offered by a game developer at Ready at Dawn Studios showed how to use Mari’s vector paint to create flow maps. To find an alternative to using Mari, I figured out a trick to create flow maps using a combination of Photoshop and Substance 3D Painter: 

1. Flow Map Painting by Substance 3D Painter 
2. Comb Map Creation by Ben Mathis 
3. How to paint flow/anisotropic/comb maps in Photoshop by Polycount 

After several trials using these techniques, I got the flow map to derive the intended anisotropic effect. To diffuse the sporadic thin bands of shine on the fur, I used a combination of effects like gloss, clearcoat specularity, Fresnel, and fuzz. To enhance the effect further, I modified the material to include detail normals, anisotropic reflection, and cavity occlusion. An optimal balance between anisotropy and specular intensity was necessary to give the fur a rough yet shiny appeal. Using a thickness map, I added subsurface scattering to the ears, nostrils, and hooves. 

An eyeball is a complex object. The cornea has a convex bulge laying over the concave part of the sclera (iris and pupil). Due to the high refractive index of the cornea, the underlying parts appear convex as well. To make eyes look as real as possible, it was necessary to anatomically mimic these effects rather than create a convex sclera. The concavity of the sclera allows it to catch the light on the valleys of the iris while also appearing convex due to the cornea.

Replicating this magical effect was quite a challenge in Marmoset Toolbag. The trick was to introduce parallax normals, volumetric scattering, and specularity to the sclera while adding refraction/refractive index, gloss, and specularity along with transparency to the cornea. Some of the resources that helped me achieve this result were:

1. Alfred Roettinger Realtime Eye 
2. How to Create Realistic Hair, Peach Fuzz, and Eyes by Vadim Sorici 
3. How to create Realistic Eye Shader in Marmoset Toolbag 4 by Aditya Anand 

Similarly, for hair cards, I used a combination of specular, gloss, anisotropy, and transparency along with clearcoat settings. The objective here was to give the hair a wiry effect with a little bit of shine similar to real-life horsehair.

The accessories had a near identical material setup in Marmoset Toolbag. 

The final step was setting up the lights. I focused on rim lights to capture the anisotropic shine in all the rendered views. In addition to this, I set up fill and key lights as well as global illumination light sources. With that, I moved on to rendering Oasis.

Conclusion

The pre-production activities took nearly a month and a half of my university term time, which involved ideation, research, concepting, testing of texturing, learning new tools and professional documentation of the R&D. The production and post-production activities spanned the following 3 months.

Through this project, I aimed to accomplish high-quality sculpts and textures with realistic presentation. One of the challenges I faced was creating good-quality fur. The lack of resources for creature workflows added to the complexity. I resorted to manually painting the majority of the textures to enhance the texture quality. 

Another challenge was the colour composition. Since most of my assets were leather-based, it blended with a chestnut shade of horse hide. Modifying the asset colour values made it stand out quite a bit. Achieving the right appeal within that narrow bandwidth took multiple attempts at texturing and rendering. Creating flow maps for anisotropy was quite challenging as well. It involved a lot of research and experimentation.

The integral advice I received that helped me tide over was that polished work is produced through feedback. If I were to put forth the best advice, it would be to put your work in front of as many artists as you can and take on board directional feedback instead of aiming in the dark. Although the internet can be a vast resource, sometimes a question is best answered through expertise. Establishing a solid network of like-minded people and industry professionals can lubricate this process.

Overall, I really enjoyed working on this project. I referred considerably to the in-game horse and saddle kit images from Red Dead Redemption 2 and The Last of Us 2. I tried to match the design proficiency and quality level. I am quite happy with the results. I received a lot of constructive feedback from my university mentor Jonathan Pearmain throughout this journey. His guidance and hands-on support were vital for me to understand the nuances of game art. Thank you, Jono!

I would also like to thank my project supervisor Jamie Gibson for guiding me and helping me understand the intricacies of anatomy. Finally, thanks to the whole Sheffield Hallam Game Art faculty, Phil Morris, Martin Jones, and Tom Battey for all your support this past year. With the experience I gathered through this journey, I wish to work on more character projects. I firmly believe I am on my way to becoming a professional artist capable of producing and executing a game-ready character. 

Thank you for reading. I hope you enjoyed the creation of Oasis!

Adarsh Shetty, Character and Prop Artist

Interview conducted by Theodore McKenzie