Giulio Marrone Dittli talked about the workflow behind the Arbennian project, explained how the real-time cloth simulation was made, and shared their thoughts on Unreal Engine 5.
Hey all, I’m Giulio Marrone Dittli and I’m a Character Artist working for both games and cinematics. I come from Florence in Italy and that is where my passion for art and sculpture comes from. I remember walking through the old town and staring for hours at the old master’s sculptures imagining all the hours of hard work and thinking that went into it. I discovered 3D while I was in high school at the age of 16 and later moved to Zurich in Switzerland because I managed to get a scholarship at an animation school called SAE Institute. Unfortunately, back then there weren’t many, if any, schools for animation and 3D in Italy, so my only choice was to move.
After a year of studying and following additional online courses in the evenings, I was lucky enough to find a job in a small startup that was working on an augmented reality game. I stayed there for 2.5 years and we managed to be featured by Apple Arcade as a flag title. After that, I decided to switch to AAA development and joined a company called Electric Square based in Brighton, UK. With it, I had the chance to work on several AAA titles (still under NDA) as a character artist. The main companies we were working for were Ubisoft and EA.
Unreal Engine 5
Unreal Engine is amazing, no other words needed. The amount of potential that all types of artists, from game to cinematics, are able to create in that software is simply incredible. And the best part is that it keeps getting better with every update. The ability to almost completely ignore polycount through Nanite or even to be able to have such an amazing quality overall of lighting and shading, all running in real-time is just completely invaluable if you’re used to offline rendering engines.
The Cloth Simulation
I started working on the cloth simulation roughly a year ago, as soon as I could do some tests with my character after the sculpting and a basic rig were ready. I was completely unsure of how to approach the simulation in general actually.
I was striving for the highest quality possible for both the shading as well as simulations, so I didn’t want to compromise any steps. Everybody was suggesting that I simply simulate the cloth in another simulation tool like Marvelous Designer and then import an alembic file into Unreal Engine as geo-cache. To some degree, that would have been a far easier choice. Yet at the same time, I was aware that the new Chaos Simulation was available directly inside Unreal Engine, and the idea of being able to control every aspect of the character inside the engine really intrigued me.
To explain exactly how and what I had to tweak inside Unreal Engine and in my rig, let’s start with the cape design. Usually, capes are placed on the shoulder of a character and their main surface of collision is the character’s backside. Additionally, they also don’t impede too much the range of motion of a character since they leave the shoulders and arms free.
The cape design that I meant for had 3 main contact areas with my character since it was at the same time in front, on the side, and on the back of my him. Additionally, it also covers the right arm and shoulder completely, limiting a lot of the range of motion.
To work around this issue, I came up with what I call a “curtain system”. Basically, the top part of the cape, which is not being simulated, is simply skinned to a set of bones that can act as a semicircular curtain around the shoulder, allowing the cape to fold back, behind the character’s shoulder. When the top part moves, the bottom part follows along while using the Chaos Simulation to achieve realistic deformations. This creates the illusion that the cape slides over the character’s shoulder as a real-life cape would behave.
To cover up the non-simulating part, I added an additional leather piece which enhanced the design of the character as well as hid my workaround. I then used an additional duplicate mesh with no thickness to act as a proxy for the simulation – the proxy was also part of the rig and shared the same skin weights as the main cape. Basically, it is possible inside Unreal Engine to add specific simulation properties to a material/mesh and then transfer that to another mesh. By doing it this way, I had the advantage to edit and work on a simplified mesh and then transpose everything onto my final cape. I then spent a lot of time customizing the simulation values to be able to get the best result out of it.
Avoiding artifacts was not that bad. The proxy worked especially well, and the 2 parts of the cape did not have any clipping issues. The tricky part was nailing down the overall mass properties of the cloth. To achieve the feeling of that cape being heavy and thick, I added some damping to the simulation as well.
Although, I had to re-render the simulation 4 times because these real-time simulations aren’t always predictable and on a few occasions I got just a bit of clipping in some frames. But with the project being real-time, it took little time to re-render the whole clip at 4k.
The Arbennian Project
I started with the Arbennian project purely out of love for the Warhammer 40,000 franchise. I’ve been a fan of the dark sci-fi universe since I was a teenager and I was always in love with the fact that it was such a vast universe that almost everything was possible. Those were the perfect conditions for me to create my own personal character with his story and twists. I remember that my first steps into the project were these silhouette studies I did to sort of try and nail down the general posture and vibe of the character.
I knew that I wanted him to be dark and low-key scary, but at the same time elegant and agile. I then developed my drawings a bit more and started doing some sculps. My main references came from obviously the Harlequins from Warhammer. Since I was going for my own personal design, I took inspiration from one of my all-time favorite movies, V for Vendetta plus the historical Venice carnival.
I had this very clear idea in mind for my character. He needed to appear as a shadowy figure, almost like a silhouette, when he’d be lurking in the shadows, with only his white mask sticking out of the color palette mostly. But if a situation required some form of combat or threat, he would unveil his blade-like weapon hidden under the cape. By doing so, he would reveal his colorful side, so to speak, and show off a variety of bright colors on both the inside of the cape and body.
A big aspiration of mine was getting the highest visual quality possible out of Unreal Engine, recreating various cinematic renders as if this was a whole animated clip. In order to have enough resolution for the textures to be able to hold up on both full body shots as well as extreme close-ups, the character is composed of 40 different materials and UV spaces. It was truly amazing seeing how fast I could build a scene and art direct it in real-time until the final color grading.
The most complicated aspect of the character is definitely the cape. The mesh itself is composed of 3 pieces. The first side is made out of leather material and the internal side – with a silk-like material and an edge trim that binds those 2 surfaces together.
In order to make all of these 3 objects follow the same simulation, I used a proxy mesh and copied the simulation values onto the actual cape. I assigned the cloth properties using the “Activate Cloth Paint” tool directly inside Unreal Engine.
In total, this project took almost 2 years to fully develop. It was a personal side project of mine, and during those years I’ve stopped it a few times to either work on some professional stuff or because I started another quicker project. It was definitely a long and tough ride. I’ve dealt with data loss, tech issues, and whatnot. But I’m happy I managed to set a personal quality standard for the character!
And this is only the beginning, I have a whole story I’d like to explore with this character and possibly more. So there’s definitely more to come in the future!
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