A Look at the Material Workflow in Assassin’s Creed Valhalla

Introduction

My name is Tsvetelina Valkanova. I’m a Senior Texture Artist at Ubisoft Sofia. When I look back, I always think that my career in the game industry started with a huge amount of luck and enthusiasm. I don’t have any degree related to my job, since there weren’t any schools or universities in my country back then, that can offer anything even remotely close to the subject of gaming. And I couldn’t afford to study abroad. My only path was to learn everything by myself. 

And jobs around here were more focused on the film and animation industry. To my surprise, I saw an ad for an open position at Ubisoft Sofia and decided to apply. I didn’t have many skills to start with, that was my biggest concern. Basic Photoshop and 3ds Max knowledge, some traditional 2D works, but that was it. I even thought that I failed my art test if I remember it right. At the interview, I felt that this was my dream job, and they probably sensed my enthusiasm and excitement, because Ubisoft decided to give me a chance, even though I was a nervous wreck.  

This is how my career started, and I’m still working here, almost 13 years now. 

I had the best opportunity to nurture one of the most significant skills in my opinion for the industry, the ability to learn on your own, especially on the go. Stuff like new software, workflows, and techniques. It doesn’t matter if you are a slow or a fast learner, it’s important to just be persistent at it. 

I still remember the time when we started using Substance Designer in our studio, there were no tutorials online, just a few graphs shared on ArtStation and Substance Share. I had to reverse engineer how every node was working by testing it countless times. That for me was such a pleasure because I love to challenge myself. It took me about 3 months of doing that to start using the program for my work. Of course, results weren’t the best at first, but it got me hooked for a while.

What Projects Have You Worked On? 

The list starts with few Nintendo 3DS games, Style Lab: Makeover, Tom Clancy’s Ghost Recon: Shadow Wars. I was still a 2D artist at the time. Then the studio had the opportunity to join the Assassin’s Creed brand with a smaller project, Assassin’s Creed Liberation for PS Vita. Here my texturing career started and it’s ongoing since then. I worked on the Assassin’s Creed Black Flag, was the sole texture artist on the Abstergo present day part of the game. Assassin’s Creed Rogue and Assassin’s Creed Origins were my next projects. 

I also had the opportunity to work on some other Ubisoft titles like Tom Clancy’s The Division 2, and The Division 2 – Pentagon: The Last Castle.

Working on Assassin’s Creed Valhalla

As I mentioned the studio had the chance to join the AC brand with a smaller title at first. And having already worked on several Assassin Creed titles, it was a natural step for the studio to take on this challenge of Valhalla.

It was such an incredible experience to work on this project. Bringing the world to existence requires a lot of collaboration between different teams within the studio and with the other partner studios. Everyone on the team has autonomy and freedom in the process of creating their assets. Starting from very solid research, working closely with the concept art. Once you have a task you are the owner and all the responsibilities related to it fall on you. You have the opportunity to bring your own ideas and storytelling to each asset. You have to organize your time and priorities based on the team and project needs. But ultimately, it all still remains a team effort, you are not isolating your work from the rest of the team, we have constant meetings, syncing, and brainstorming together for each location. Everything has to be a part of a consistent and well-thought world. Therefore, collaboration is very crucial. 

Nowadays, with the pandemic stressing the world, our whole studio is working from home. My work is not affected by it very much in terms of production. But oh boy, do I miss talking to real people, not just calls, getting coffee and discussing various art-related topics with the colleagues. 

What Tasks Did You Have?

I joined Valhalla in the last year of its development when there were already established workflows and demands for the project. After I joined the team all the work and tasks on tiling textures for the Jotunheim world kits were passed to me. That included the awesome Root textures, the huge Keep and stone tiling materials we have, all the house kit textures. We have a very dynamic workflow that gave me the opportunity to work on props as well, like the Narrative stones in the Vault, which was one of my favorite tasks. I had to come up with all the ideas about them, had to interpret the stories in a Viking looking style, even made a quick concept art to showcase that to the directors. Once I had their approval, I’ve proceeded to sculpting, creating lowpolys, and texturing them. Also, I did some carved stone props that decorate the city walls and other places.  

What Software Did You Use?

We don’t have a mandatory workflow with specific programs to use. This gives me the freedom to choose different approaches to each asset. My tool palette consists mainly of ZBrush, Substance Designer, Substance Painter, 3ds Max. I choose which tools to combine depending on the tasks at hand and my preference. I’m very confident in these tools not only for making textures but other assets as well. Part of my work is creating props and modules, too. This makes my job even more interesting. And I have the flexibility to cover whatever needs the project has.

Creating Materials for the Jotunheim World

Jotunheim was a thrilling world to work on. It’s not the average realistic world we are used to, it brings its own little fantasy and mood. 

We have a very simple material workflow, and once you have all the textures needed, it’s almost plug-and-play afterwards. We rely heavily on vertex paint to blend two sets of textures together. This gives us so much variety with fewer resources and textures. We always have to think about how one material ages or transforms with the blending and provide that texture variation.

I’ve worked on three main themes of textures for this world:

• The Jotunheim Roots - consisting of one material for the roots and one for the barks. Each material with its two sets of textures blending together. 
• The Jotunheim House kit - two stone wall textures – the only difference they had was the size of the stones, they both blended with snow; I did various trims with golden and painted ornaments; decals with painted wood carvings; base stone and wood textures; basically all the materials for the houses, except the roofs. 
• And last but not least, the Jotunheim Keep, city walls, and other stone structures - here I made 10+ stone texture variations. 

Bark Materials

Coming up with the final solution and looks for the roots and barks was a team effort involving Petar Zvezdanov for the bark models and photogrammetry, Georgi Hristov for his awesome Houdini work on the roots generation system, Samuil Munis and Kosta Milev for the roots shaders. We had a few brainstorms, a few tests on what we could achieve. As a result, the final assets consisted of the procedurally generated roots and barks on top of them. The trickiest part was how we were going to achieve the same texture and material quality for faraway and close to the player views while keeping the texel ratio consistent. We ended up with an awesome shader that uses unique textures for the faraway view – this is where Petar Zvezdanov’s bark scans come in to play. And as you go further from the roots we softly blend between the unique textures and my basic tiling textures, ending up with very sharp and dense textures for the middle and close-up views, and very natural looking barks from the faraway view. My bark textures were created fully in Substance Designer with a few color tweaks in Photoshop. 

For the roots base beneath the barks, we used only the tiling textures I’ve created. The goal was to resemble a vine tree structure that looks very twisted, and beneath its thin bark, it was usually a very smooth surface, with little breakups of that smoothness on some spots. Both of the surfaces were done in Substance Designer. 

Once I have the refs and ideas of what I’m going to build, my workflow in Substance Designer is really simple. Like most artists, I start building up my material by doing the height first and breaking up each different detail on separated framed nodes. That way, I can clearly see and reuse the mask for the details later in the color and roughness creation.

Stone Surfaces

The stone surfaces I made were used in the Keep and other structures around the city. They are a combination of quick ZBrush sculpts, Substance Designer’s graph, and of course some Photoshop color tweaks at the end.

I started with a plane in ZBrush. With the default trim and clay brushes, I’ve created a few quick stone looking shapes. Not adding too much detail here, just the big and medium shapes. Then I imported and baked the base textures I’d need to proceed with my work in Designer. Key maps I needed are normal and height. These maps gave me a solid start in my substance file, so I could generate everything else needed for my material based on those two maps (curvature, ambient, various masks). The only thing left to do was to add some smaller and micro surface details to them and color. 

Flexible Texturing Workflow

In our team, we haven’t used scanned data yet, except for the barks in Jotunheim, so it’s all manual work. And since we are not restricted by software use, I like to keep things interesting and switch between various techniques. For example, if I were to create a brick wall, I would probably start with a ZBrush sculpt, then bake and import my normal map, ambient, masks, and curvature in Substance Designer, create an albedo there and add details if necessary. This can totally be switched around and I can use only Substance Designer if I wish to, or Substance Painter – as long as I have the same consistent quality in the game. 

Of course, during production time, there are some shortcuts of doing everything from scratch for every single texture. I have plenty of old Substance’s graphs on my PC, we also have an internal library from the older projects that can be used at least as a reference to base your work on. It’s really dependent on the deadlines we have. I like starting my work from scratch, but it’s just not possible every time. Substance Designer is the best when it comes to that, you can always tweak an old graph just a little and get totally different results in a very short amount of time. This is very flexible and convenient. 

Lessons Learned

The most valuable lesson for me was to take my time for preparation before starting a task, talking with everyone on the team, planning, and researching. In the end, this will save you more time, give you a great direction, and then the only thing left is to dive in and create. 

My main challenge for this project was the Keep structure. It’s a huge fortress of stone that uses a very little number of textures and module pieces. We had to come up with a solution on how to avoid tiling and repetition but still keep it interesting. It took us a while, experimenting and tweaking everything, modules, textures, adding decals to break up some of the repetition. I experimented a lot with color variations, trying to avoid material surface looking like concrete as we wanted it to be 100% stone. In the end, it all turned out great. 

I’m very much used to the quality expected for the Assassin’s Creed brand, and keeping everything consistent is a much easier job since we adopted the PBR workflow a few years back. It all comes down to how many realistic-looking textures we want for the game. Once that is set as direction early in the project, it’s easy to follow. Valhalla has a lot of scanned data, for the terrains, cliffs, some walls, etc. To be consistent, we had to keep all the textures the same quality. Some surfaces are more challenging than others, but overall it’s not that hard to mimic scanned textures. I build up my materials by dividing my details into 4 categories: big shapes, medium shapes, small details, and micro surface detail. By gathering and observing references for those 4 shapes and details, you can easily create every material very closely resembling a scanned texture. You can even use scanned data for reference, study it, and replicate it.  

It’s very challenging to work in such a dynamic industry. Tools that we used 10 years ago don’t apply nowadays. But that’s what I love, especially the constant need to improve yourself and to learn new things. This keeps me on the edge and makes my job feel fresh every time I start working on something. 

Tsvetelina Valkanova, Senior Texture Artist at Ubisoft Sofia

Interview conducted by Arti Sergeev