Here's How You Can Recreate Sekiro's Cannon Arm in 3D

Introduction

Hello, my name is Naoman Ahmad! I'm a Game and VFX Artist based in Montreal, Canada. I've worked on movies like Transformers Rise of the Beasts, Black Adam, Stranger Things, and so on. I've always been into games and for as long as I can remember, not just playing them but getting lost in them. I got into 3D when I was 16 or 17 years old. I downloaded Blender after watching some free game dev courses on YouTube. After that, one of the first things that I modeled was a sword. It was a pretty terrible model, and the software was overwhelming. But something clicked in me. After making several more attempts, I got lost in the process. That's when I realized I wanted to make a career in Games and VFX.

Fast forward several years, and I'm working on AAA movies with studios like Scanline VFX and MPC Film. I got obsessed with Dark Fantasy, Dark Souls and Berserk. The "Beauty in Decay" was an aesthetic that I could relate to. And of course, the FromSoftware games have plenty of that.

The Wolf Cannon Prosthetic Arm Project

I was flipping through pages of the Souls Art book that had plenty of Sekiro shinobi tool fan designs. I landed on the Great Wolf Cannon design by Jon Comoglio. It was so well done that I knew I had to model this. I texted him on Twitter asking for permission, not only did he say yes but he also sent extra unused sketches, gave me notes, and shared his references.

The Arm Modeling

To start, I had blocked everything out in ZBrush, just standard primitives and very low-resolution sculpting. Then, I went back and forth with sculpting out the forearm and hand in ZBrush while poly-modeling the cannon and the cannon holder in Maya.

This type of cannon doesn't exist in real life, and the concept can only explain so much. So, naturally, I had to improvise in certain areas, including the traditional look of the wolf head. Although the concept depicts the wolf head as Eastern European inspired (Witcher comes to mind), I struggled to incorporate it effectively in 3D, as it clashed too heavily with the Asian themes. Therefore, I had to find a compromise and turned to traditional Chinese sculptures for inspiration.

The gold trimmings are what defined this asset for me. For those, I used Chinese engraving patterns that I discovered online. I combined different patterns, created some of my own, and traced over them in polys. Subsequently, I projected/snapped them to the surface and extruded them. Similarly, I applied the same process to the pattern around the emblem, but I used a bend deformer first. As for the emblem itself, the one in the concept was illegible, so I opted for a different approach. I stumbled upon a dragon emblem on Pinterest, sculpted it, and then refined it in poly.

The rope was kind of a nightmare. I used a really long helix curve to start and tangled it up by hand. It took a long time but it gave me the exact result I wanted. In the end, the bundle got baked down onto a cylinder.

Lastly, I used Marvelous Designer for the bandages. It was just simple wrapping with light sculpting on top, nothing complicated. I tried to add some micro noise early in ZBrush but it ended up being unnecessary, it isn't really visible in the final render.

Some Words On The Topology And Unwrapping The Model 

For the topology, I aimed to keep it under 80k triangles. I began by blocking out the low-poly model and continuously performed test bakes in Marmoset Toolbag 4 using different lighting scenarios. Once the bake appeared correct and didn't exhibit any visible faceting, it was ready for texturing. As for the UVs, I took care to straighten the shells as much as possible and packed them into two UV sets: one for the arm and another for the cannon.

Texturing

This was a very texture-heavy project, there was a lot to unpack. The main metal for the cannon had a lot of trial and error before I got it right. I tried to make the material from scratch but just couldn't get that cast iron look. So instead, I used an iron texture and photoshopped it to be seamless. It ended up looking a lot better, and it was much faster. Then, I used it to establish the base and height before making more adjustments to it myself.

From there, I used edge-wear generators primarily as a foundation. Then, I hand-painted the weathering and damage using textured brushes and decals. I believe a lot of texturing should be done by hand and procedural workflows should only be used to speed up the repetitive parts of the task.

The forearm was very interesting to make because, based on Sekiro lore, it appears to be sculpted wood with rot, which gives it the appearance of bone. The wood itself was also tricky, but eventually, I achieved the desired result. To begin, I used a Japanese oak texture as a Base and extracted Height information from it. Additionally, I incorporated additional Height details using a Directional Scratch Grunge Map. The rotting effect was achieved by combining dirt, grime wear, and touches of green discoloration.

I did the same for the fingers but with a green finish and much less rot.

A similar workflow was used for the wood holder but with more of a generic soft wood texture and reference that looks almost like the top wood layer was 'smeared" off due to aging.

The hand wrap was fun. The main reference I used here was my boxing wraps. I added the indentations of the cloth, some extra wrinkles, and some edge tears. Since this geometry was one-sided in the low-poly model, I used opacity with a slight height variation to create the tear effect.

To finish off the texturing, I used some simple hair cards to have the wrapping and rope its final touches.

Speaking of the textures for the cannon, the textures are a standard PBR workflow with the addition of Opacity Map for the cloth tear and rope fray cards. As for the ornaments, I initially sculpted them and then refined them further in Maya. By cleaning up the polygons, I achieved a clean bake that produced satisfying results. For those interested in creating micro details during modeling, I highly recommend creating an ID mask, as it greatly saved me time in the process.

Rendering and Lighting

For the presentation, I wanted to go with a warm autumn feel. That feeling of comfort in between fights that FromSoftware games are known for. For rendering, I used Marmoset Toolbag 4. The lighting is adjusted for every camera angle, each to show something different. Most of the lights were 3-point setups with some extra key lights to emphasize certain parts of the model, mainly the roughness. The only real post effect I used was Dept of Field. I made sure to keep it low, I didn't want to hide my model but rather have areas of focus.

Final Words And Pieces Of Advice

My main advice to any beginner is that a simple well-done model is always more impressive than a decent but complicated model. Not only does it look better on a portfolio, but it will give you an opportunity to learn so much in such a small amount of time. You'll learn a lot more about yourself and your work habits by completing projects than you would by starting them. Moreover, completing projects promptly helps you maintain motivation, which can be carried over to the next bigger projects. In the past, I made the mistake of rushing into creating a mech without sufficient practice, leading to frustration and an inability to finish the project.

Naoman Ahmad, 3D Artist

Interview conducted by Theodore McKenzie