LogInAdrián Bautista Gil shared a step-by-step breakdown of crafting realistic tarnished metal with Substance 3D Designer.
Introduction
Welcome, readers, to this digital space that 80 Level has kindly offered me and which I truly appreciate. My name is Adrián, and I am a Material Artist from Spain. My journey into the world of 3D modeling began during my Bachelor's Degree in Video Game Development. Although the program was primarily focused on coding, we explored a bit of 3D, which sparked my interest and led me to pursue a specialization course in this field.
As I delved deeper into 3D, I quickly realized I enjoyed shaping environments and building assets. However, I found that tackling entire environments required mastering too many skills at once. To make the process more manageable, I decided to focus on textures and materials. These elements are the foundation of any visually compelling 3D world and an ideal starting point for developing a deeper understanding of how surfaces can tell their own stories.
I completed my studies in January 2023. Unfortunately, I haven't had many opportunities to contribute to professional projects in the video game industry yet. Nevertheless, I am incredibly grateful to Jordan Pioneers, a production company that gave me the chance to design some environments for the production of Sesame Street.
Breakdown
Enough with the introductions – let's dive in and explore the process behind this project. I decided to create this material as part of the Nodevember challenge, specifically inspired by the Dragon Sanctuary prompt.
Usually, I like to gather a solid collection of references to shape a clear vision of what I want to build. However, given the time constraints, I initially conducted a brief search through Pinterest and Google Images. I eventually chose an incense burner with Chinese motifs as my primary reference, adding more as I progressed through the material.
My initial goal was to replicate the incense burner itself. However, as I began constructing the dragon and testing an opacity mask using the filler shapes from the reference, I decided to pivot away from recreating the burner. But let's not get ahead of ourselves – let's start with the core structure of the material.
Engraving the Relief
Although this was my first attempt at replicating a sculpture in Substance 3D Designer, I had a clear idea of how to approach it – or at least how to get started. I began with the body, focusing on two main elements: a tileable texture for the dragon scales and splines to shape the body easily.
For the basic shape of the scales, I used a circular shape that I tilted using a Gradient Linear 1 and further modified with the Trapezoid Transform. I then applied a Non-Uniform Blur to soften and control the curvature of the edges.
Next, I used a Tile Generator with a Transform to create the scale pattern. To add subtle irregularities, I applied a Slope Blur to break up the edges slightly. The final step for the tileable texture involved curving the surface to replicate the curvature of the body.
With the Height Map of the scales complete, it was time to map it onto the body using a Quadratic Spline. For this, I used the Spline Mapper Grayscale node.
I repeated this process for the dragon's crest with a slight adjustment: since the dragon in the reference image twisted upon itself, I had to divide the crest into three distinct sections – the top, the bottom, and a transitional piece.
For the top and bottom sections, I used the same texture trim but adjusted the spline's position and the parameters in the Spline Mapper to flip the bottom section downward.
Meanwhile, for the transitional section of the crest, I took a different approach. I used a Height Extrude to generate the trim and positioned the extruded version as if viewed from above. I added a few tweaks to refine the shape.
Once all the body components were ready, I blended them. I applied some blurs and gradients to ensure the transitional crest fit seamlessly with the rest of the Height Map. You can see the node structure in the screenshot below. – I acknowledge there might be a more efficient way to avoid using four separate mappers. However, as someone relatively new to working with splines, this was the best solution I could achieve.
The Legs
The process of building the legs was relatively straightforward. I modified several Basic Shapes and used a series of Blends to incorporate the scales I had already created, along with the additional details. To ensure the legs fit correctly in each position, I split them at the knee joint.
Head & Tail
Initially, I planned to create the tail and head by deforming basic shapes, as I did with the legs. However, once I realized I wouldn't meet the deadline, I shifted my approach and used the SVG node to define the main shapes instead.
After preparing the SVG shapes, I started with the tail. This part was relatively simple – I needed to add a thick edge along the border. To achieve this, I used an Edge Detect combined with a Histogram Range to adjust the height of the interior field.
For the head, I employed a Non-Directional Blur to create soft bevels on the edges. Using masks, I selected a few areas I wanted to bevel more prominently. The Flood Fill to Index node proved invaluable for this task. Next, I added the eye and ear details, followed by a couple of Slope Blurs to subtly break the edges.
Once these elements were complete, the head and tail looked like this. After blending them with the other parts, the primary engraving was finished. I gave it an overall pass with a Slope Blur and Warp to introduce more intricate details across the surface.
It's worth noting that I used the same technique to create the clouds. Although they were a last-minute addition after the material was nearly complete, they blended seamlessly with the overall design.
Building the Base: The Bronze Surface
At this point, I did a quick pass to generate the rest of the maps, and this is how the material looked at that stage:
It's not great, but at least the dragon displacement looked promising. As I mentioned at the beginning of this article, my initial plan was to follow the incense burner reference, but I had already abandoned that idea by now. My current challenge was figuring out how to fill the empty space without drawing attention away from the main element.
This was when I decided to pivot and create something resembling a bronze sculpture. I began gathering more references to guide me, but I was still unsure how to tackle the noisy background.
While researching, I came across information about how bronze sculptures are typically crafted. They're often made by creating an initial clay model, which is then used to form a mold where the bronze is poured. Inspired by this process, I realized I could emulate a similar effect by mimicking brush strokes, as you might see on a clay surface.
For the brush strokes, I created a few variations with a simple setup and scattered them using a Tile Sampler.
In addition to the strokes, I added extra noise to enhance surface variation. I used Clouds 2 combined with Slope Blur for larger and medium-sized variations, while Grunge Rust Fine worked well for smaller details.
With the Height Map completed, it was time to move on to the maps that would transform this height information into a tarnished bronze surface. We've made great progress, and this is the perfect moment to dive into – or at least briefly touch upon – some key principles for metallic surfaces when using the Metallic/Roughness workflow to create PBR materials.
PBR Materials: Metals
If you're interested in delving deeper into the technical aspects of Physically Based Rendering (PBR), I highly recommend these resources:
For a better understanding of metals specifically, check out this insightful video by Outgang:
These resources were invaluable for me in overcoming the challenges metals presented, as they were quite a headache.
What is a PBR model?
PBR models define how light interacts with a surface and how it behaves as it passes through different mediums based on an array of physical properties. These properties are determined by the data in the textures we create. For the Metallic/Roughness workflow, the key textures related to metals are:
Metallic Map
This map indicates whether the surface is metallic or non-metallic. Metallic areas are represented in white, while non-metallic regions are in black. In most cases, this map functions as a binary mask. However, for materials like tarnished metals, where transitional areas such as rust exist, gradients are necessary to accurately depict these in-between states.
Yes, I do use grayscale values in the Metallic Map when needed, as they effectively represent surfaces where metallic properties gradually diminish due to corrosion or wear.
Base Color
This texture can be tricky if we don't fully understand what it represents. Its data varies depending on whether the material is metallic or non-metallic:
- Dielectrics (Non-metals) – The Base Color represents the diffuse
reflected color, which typically falls between 30–50 sRGB on the low
end and up to 240 sRGB at the high end. - Electrics (Metals) – Metals lack a diffuse component; instead, the Base Color represents the reflectance value – the amount of light reflected specularly. Non-metals have a hardcoded reflectance value of 4% (59 sRGB), but metals reflect much more light, ranging from 70–100% (180–255 sRGB).
Key Takeaway
As the Metallic Map transitions from non-metallic (black) to metallic (white), the Base Color data must also increase its sRGB values to reflect the higher reflectance of metals. Pure metals should reach the 180–255 sRGB range. To ensure accuracy, the best tool to use is the PBR Validate node.
In the screenshot above, the same Base Color is paired with two different Metallic Maps:
- Incorrect (Top): The red areas indicate metallic zones with reflectance
values that are too low. These areas can be corrected by either increasing the Base Color's luminosity or reducing the metallic value in the Metallic Map. - Correct (Bottom): The green areas show that the values are now within the PBR spectrum.
Base Color & Metal Map
Now that we understand the primary maps needed to create our tarnished metal and how they interact, let's delve into the process I followed. For the base color of the bronze, I primarily used Curvature Maps and repurposed the Grunge Rust Fine to create various Gradient Maps, which I blended together to achieve a weathered effect.
For the patina, I combined the Grunge Rust Fine with the Grunge Galvanic Small and applied a Gradient Map extracted from the Curvature Map.
To merge them, I created a mask using the Dirt and Distance nodes.
Regarding the Metallic Map, I converted the base color to grayscale and combined it with the patina mask. I then adjusted the values for the bronze and patina to ensure accuracy. As discussed earlier in the PBR section, I used grayscale transitions to depict areas of bronze that had begun to rust but still retained some metallic properties. Finally, I verified compliance with PBR principles by utilizing the PBR Validator node we reviewed earlier. This method ensured that the tarnished metal was both visually compelling and physically accurate.
Roughness & Normal Map
When we build the Roughness Map for metals, we have a lot of freedom, and it depends mostly on the look we are looking for; weathered metals will be rougher than polished ones. On this occasion, I added a rougher look to areas that were prone to rust or already rusted.
On the other hand, the Normal Map was pretty straightforward. I converted the Height Map to Normal and combined it with extra normal details for the patina. I took the same Grunge Rust Fine that I used for the color, applied a Slope Blur Grayscale, and masked it with the Patina Mask.
Final Touches: Rendering Setup & Lighting
For the final renders, I used Marmoset Toolbag, which I find to be the most comfortable tool for rendering. The quality it provides is excellent and makes it easy to achieve professional results. I usually follow a consistent setup for my renders:
Camera Settings
- Tone Mapper: I always set this to ACES for realistic color grading. While I typically leave the curve to its default setting, I sometimes switch to High Contrast depending on the desired look.
- Post Effects:
– Sharpness: A slight boost helps enhance details.
– Vignette: Adds subtle focus by darkening the edges of the frame.
– Grain: Gives a cinematic touch.
– Chromatic Aberration: Adds a realistic lens effect.
Lighting Setup
For lighting, I combined a skylight with three light sources:
- Rim Lights: Two lights were positioned to frame the asset and enhance its silhouette, making it pop against the background.
- Fill Light: A third light was used to illuminate the areas left in shadow and balance the overall exposure.
- Key Light: Normally used as the primary light source to draw attention to the focal point. However, for this specific project, I used the skylight to fulfill this role.
This setup ensures that the model is evenly lit while emphasizing its details and depth.
Resources for Lighting and Rendering
If you're looking to improve your lighting for render presentations, I highly recommend these posts:
Conclusion: Breathing Life into Metal
Thank you for making it to the end of this breakdown – I hope you've found something useful in the process I've shared. Creating this bronze material took me roughly 8 to 10 hours, spread across three days of working in my spare time. It was both a rewarding and challenging experience, especially when tackling the sculpture of the dragon. This was my first time crafting such detailed and specific shapes entirely within Substance 3D Designer, and while it pushed me out of my comfort zone, it was incredibly satisfying to see the material come to life in the end.
One of the most enjoyable aspects of this project was combining techniques I already knew to construct the dragon's intricate engravings. At the same time, it was equally exciting to dive into new territory, researching and building the brushstroke generator to achieve the desired carved effect.
Final Tips
Some of these tips are applicable not only to metallic materials but to dielectrics as well since much of getting a good result is based on attention to detail:
- Start with Strong References
Always gather high-quality reference images before starting. Look for real world examples of aged metals, focusing on the nuances like oxidation patterns, scratches, and weathering. Understanding how these details interact is key to creating believable material. - Learn from Other Artists and Photogrammetry Assets
Don't hesitate to study materials created by other artists. Platforms like ArtStation or specialized tutorials can give you fresh ideas. Similarly, examine photogrammetry assets – they can provide invaluable insight into how various texture maps (albedo, roughness, normal) contribute to a realistic look. - Follow PBR Principles
Stick to the PBR workflow. Ensure your metals are accurate, and always remember that metals shouldn't have non-metallic properties like a diffuse color. For aged metals, focus on balancing the interplay between metallic areas, rough surfaces, and patina layers to maintain physical accuracy. - Ask for Feedback
Don't hesitate to reach out to artist communities for feedback or advice. Groups like Future Material Artist (FMA) have been incredibly helpful in my experience. They are active, supportive, and filled with talented individuals willing to share tips or insights. Sometimes, an outside perspective can help identify areas for improvement you may have overlooked.
Thank you again for following along – I hope this project inspires you to explore new challenges in your own creations.