What is good 3D rendering and why does it matter for fashion?

If you have been working with 3D fashion for a while now, you know how difficult it can be to give your garments the realistic look your customers are expecting, which means achieving a good rendering result. But what is good rendering and how can you achieve it?

The Stitch team has been talking with several fashion designers and product developers in fashion brands, conducting research to understand what good rendering means for them. Some of the insights resulted in this article. If you're not that familiar with 3D workflows, you can also enjoy the reading and learn what rendering is, how it works, and why it is so important for fashion.

What is rendering and why should I use it in fashion?

Rendering in 3D design means creating a photorealistic image from a 3D model, like a virtual photoshoot. A virtual camera takes a picture of a 3D model, and the rendering engine produces a high-quality 2D image. In fashion, we call a render the final image of a 3D garment, where you can see it in detail and from different angles.

You can render in different 3D design software, but most require your computer to process the rendering. This can take a long time and delay your design process. Investing in high-capacity hardware is another option, but it can be overly expensive.

According to Rebekka Seyffarth, 3D Product Specialist at Stitch, "If you're not investing in expensive hardware, rendering just one high-resolution image locally on your computer can take several hours. It can slow down everything else, making your computer unusable for that time." To avoid this problem, consider using a cloud-based rendering engine. It can process your renders on a cloud server, rather than locally, saving you time and resources.

More than just being a digital representation of your physical garment, a 3D render can optimize many steps in the fashion value chain. At the beginning of the season, renders can help you discuss design ideas in a much more detailed way, replacing technical drawings and even physical prototypes.

Towards the end of the season, the images can be combined to present the collection to merchandisers and sales teams. By using digital tools such as digital showrooms, presentations can be enriched with 3D assets and made available more quickly.

Once the collection is released, 3D content can be used in e-commerce and other digital sales platforms to create more immersive and engaging experiences. A high-quality render can showcase details that may not be visible in photos, providing a more comprehensive view of the product.

How to identify good rendering?

When we say "good rendering," what does it mean? A high-quality render should look as detailed as a photograph. We want the digital garment to look realistic, and that means putting effort into all the details.

Resolution, for example, affects the amount of detail displayed in an image. The higher the file resolution, which means the more pixels it has, the more details are displayed. Additionally, the rendering process occurs in cycles, with each cycle making the image sharper and more detailed. Therefore, the number of cycles you choose for your render will influence how long it takes and the quality of the image.

But even with the render quality set to "high," there are a lot of visual cues that can throw us off, and not all of them depend on the designer. Seyffarth shares that while creating in 3D, you can set everything as you want and still think, "That does not look like a real garment!" Usually, it has something to do with the fabric and its surface texture. If no texture maps are used in a digital fabric, the garment can look like it's made of paper or plastic. The maps themselves should be of high quality to show all the details in the render later.

Other surface effects can be applied to make a render look more realistic. In 3D, shadows are calculated based on the direction of light through the surface of the garment. To show texture, you can include small bumps in the fabric, with each thread creating its own tiny shadow. If the material you choose has a reflective effect, it should be displayed as well. Additionally, some fabrics or trims can allow the transmission of light, so you need to be able to make them transparent or translucent.

The lighting settings are also important for the rendering quality. Additionally, the quality of the rendering engine being used is crucial. Seyffarth emphasises that "the rendering process cannot magically improve the quality of a low-quality garment. If the garment itself - the geometry, the draping - does not look realistic, the best render settings in the world will not be able to turn it into a photorealistic image.”

Perfection vs Realism: Which Render Do I Need?

There's a dilemma when discussing good rendering with fashion teams: should I go for perfection or realism? This means that not every 3D garment created and rendered to the highest quality and standards will give us realism.

Maaike Molemkamp, designer at Stitch, related a situation she heard from research interviewees: "Some designers question whether they want a perfect or a realistic render. Realism would be a shirt with some wrinkles and little imperfections, as the perfect render might look fake. Real is not perfect. Real has flaws. As a brand, you need to decide what you want: perfection or realism?”

Saying that, it’s important to question why you need a high-quality render and where you're going to use it. Rendering takes time, and the file sizes are considerably large, occupying large spaces on your disk and/or servers. The higher the quality, the longer the rendering process will take, and the larger the file will be.

Think about the use case of your render. If it is just for a quick check, a low-quality render might be enough. If the image will be shown in an important collection presentation, on a big screen, or even be used for e-commerce, it is better to go for high-quality and wait a bit longer for the render to finish.

Fashion needs for 3D rendering are a bit different from other industries that also use 3D. As a fashion brand, you can be flexible and have different outcomes depending on your needs. That's why it's important to partner with those who have been through the same journey as you and understand fashion from the inside.

If you want to continue this conversation on how to have high-quality renders in a seamless 3D workflow, you can get in touch with the Stitch team through the website or the LinkedIn page.