How To Create Chinese Yuan Coin Material

Introduction

Hello, my name is Dai Qi Yu, aka Aiden, an Expert Texture Artist at Ubisoft Montreal. It's been a pleasure to work on Tom Clancy's Rainbow Six Siege and For Honor. I focus more on characters and some of the environments.

This coin material is an interesting one I wanted to do. I saw there were some coin materials others made, but it seems they're missing some Chinese culture-related stuff, so I chose to make it. With this project, I wanted to try to make an atlas by using various programs such as ZBrush, Photoshop, and Substance 3D. Then I could scatter it easily.

Workflow

First of all, we need to find some good references as the base:

For the flower pattern, I imported it into Photoshop, adjusted the contrast and visibility, then imported it into ZBrush as a texture. I then opened it in the Spotlight editor, allowing us to sculpt it according to the coin reference. We just need to take some time to adjust it back and forth between Photoshop and ZBrush. Eventually, we will get a height map from ZBrush by using Make 3D in Alpha tools.

As for the characters and text, I just made them in Photoshop by using tools such as the brush, path tool, pen tool, and so on.

Then we can import all the resources into Substance 3D Designer.

Made coins separately, one by one:

For the height map, I like to use Histogram Range to balance the height, so that it can help to keep all the height maps of coins having the same value. The result will look consistent and better.

Then place them as a 3*3 grid.

For the color, in order to select part of the coins easily, I used the Flood Fill node to have a variety of gray values for the coins, then used the Histogram Select node to select which coin I needed. It helps me to fill in the color for the part I need to fill.

Then we can start to add some detail and metal wear on the surface. It's easy to do, I just used Dirt Generator node in Substance 3D Designer, then connected the curvature, AO to the Dirt Generator, then just had to tweak the controller to get a satisfying result. You can also add additional detail, such as damage, scratches, and so on. You will have a variation of the roughness and metallic detail.

After the above steps, the atlas material is done.

The next step is to integrate this atlas material into a new material graph. For this workflow, I used Atlas Scatter to place the coins randomly on the surface by adjusting size, rotation, position, and so on, eventually, we will have a random result.

We can expose some parameters, such as the color of the coins, size, rotation, and height scale, and so on, so that more variation of the coins can be achieved by those parameters.

Conclusion

I spent about 2 days finishing the material, and it was a fun process. The main challenge, I would say, was making sure the height map looks good, especially for the flower pattern, and also the height map blending for atlas scatter is another challenge. I had to make sure there is not too much cross-through between each coin/height map. In order to solve this problem, I reduced the intensity of the height map of each coin so that when I scatter them, the final height map looks better.

As I said, when you want to do an atlas material to scatter, you should be careful about the height map for each element, the intensity and contrast of the height map of each element shouldn't be too intense.

That's all I did for this funny material, hope you like it. Thanks!

Dai Qi Yu, Principal Texture Artist

Interview conducted by Emma Collins