Creating a Japanese Cafe Diorama in ZBrush, Houdini & Substance 3D

Introduction

Hi, I am Atsuko Nagano. I am working in the video game, CG animation, and VFX industry. Recently, I have participated in the production of Fantastic Beast: The Secrets of Dumbledore and Elden Ring. I started playing with 3D art when I was in university. I got my basic knowledge from my first job. However, when I decided to commit to the CG animation/VFX industry, I started to self-learn from YouTube, by reading books and official documents. I also attended some online workshops.

The Cafe Block Project

In the past, I pursued realistic art pieces with high detail and I really wanted to challenge stylized art. It is also a good time to learn something new. I had never used Arnold before, so I chose it to render. When I was in Japan, I really liked traditional Japanese houses that were renovated into cafes and shops, they are adorable. I was also inspired by Mateusz Urbanowicz’s "Tokyo Storefront".

Modeling

I put a time limit of about a month for myself to create the entire set. The main challenge was the stylized surfacing with Arnold. I started by blocking and setting camera angles to determine which area to be focused on. After the main geo, like the wall, ground, trees, bushes, and roof, were blocked out, I quickly moved on to texturing, lookdev, and lighting. I did some RnD with Houdini at the same time. The process was back and forth between these phases.

After the direction of style was decided, it was time to tell a story by adding small props.
For example, a couch for customers, a cup left on it, a water tap in the alley, signs, etc.

I created oversize props intentionally to emphasize the diorama feeling (for example, gutter/pipes). This process needs to be handled carefully. All the assets still need to respect the real-world scale, only selective items should be adjusted.

Unwrapping

The UV was done by Maya's UV toolkit since I hadn't decided what the final render size would be. I set texel density to 4096 = 4m (about 10.24pixel/unit) just in case. I also paid attention to the UV orientation. It should respect the direction of the texture pattern in most cases. I sorted the direction of the wooden door from the example image. It followed the same direction as an actual door structure so it would be much easier to manage in Substance 3D Painter.

Texturing

I used PBR textures from Substance 3D Assets, Megascans, and Textures.com as the base for my stylized textures. They were all created in the PBR metal/rough workflow in Substance 3D Painter.

I sculpted the street tiles in ZBrush and combined the tileable textures with geometry assets to get natural-looking bump details.
  

The original material is from Substance 3D Assets. Its high complexity makes it noisy for my asset. I kept some major but removed minor details and made sure that the painting styles and the number of details are all in sync across the whole asset.

I chose to work on assets that cover major areas first, like the wall and roof tiles. I put my references to the side of the screen comparing them with the render and adjusting the color palette accordingly. This iteration was repeated until I was satisfied. Thank you, Patrick CN Wong, for giving me advice on the color palette and texture creation.

Houdini

Houdini was a powerful tool in my workflow. Even its simple functions gave me more adaptation. I used Houdini to create small assets like concrete blocks, bamboo curtains, roof tiles, and the cloth sign. The non-linear workflow allowed me to make adjustments if the assets didn't fit the scene. Here are some examples of the workflow:

Pipes

1. Create a curve.
2. Use a Group node to select points and assign the selection to the group.
3. Copy geo to selected points’ group.

The bamboo curtains were created in the same way.

Concrete Blocks

The following Houdini trick is shown in Masaya Sugimura’s workshop.

1. Convert base geo to VDB
2. Convert VDB to polygon
3. Boolean steps 1 and 2

Rendering

In the beginning, I tried using photo-based HDRI, but it couldn’t give me the result I wanted. I found some Painted Anime Skies HDRIs, they create unique vivid lighting. Adding directional and rim lights emphasized the mood, and area lights emitting from objects like signs and lamps supported storytelling.

Using the tilt-shift lens effect in post-production is the key to enhancing the diorama feature to the asset.

I used Z-Depth pass on ZDefocus and Defocus nodes in Nuke to control the focus area.

I also wanted to add the chromatic aberration effect. In order to achieve it, I decomposed the image to RGB and shifted the colors along the edges. Fumi Sugawara developed a Nuke node structure that helped me to achieve the final image.

Conclusion

The main challenge of this project was to finish it within the time limit even if I might not have been completely satisfied. We artists have lots of ideas and inspirations, but this passion dies quickly, which results in a lot of unfinished personal projects. However, if the projects are finished and they can be put in my portfolio or if I can move on to my next piece with the experience, I gain from them.

Atsuko Nagano, Environment Artist

Interview conducted by Theodore McKenzie