Offline vs Real-Time Rendering

With 3D rendering increasingly being used in the fashion industry, we wanted to learn more about how brands can utilize it, and what the future holds for this technology.

In this VNTANA Live discussion, we welcomed Yazan Malkosh, Founder and CEO at Swatchbook, Anna Violette, 3D Apparel Specialist at VNTANA, and Richard Evans, VP of Growth Marketing at VNTANA, to discuss it in detail. 

Anna shares her thoughts on 3D rendering, and explores the differences between real-time and offline rendering, the use cases in the apparel industry, and the challenges of using this technology.

To learn more, keep reading for the top takeaways from our discussion or hit play on the video below. 


What is real-time rendering?

Real-time rendering creates immersive experiences involving 30 to 60 images per second to create a seamless and responsive experience for the user.

This type of rendering requires PBR maps, aka physically based rendering maps, which is a set of textures that define the physical properties of an object.

This technology can be used in web viewers, digital showrooms, eCommerce platforms, game engines, AR, VR, and even the Metaverse.

What is offline rendering?

Offline rendering is sometimes called pre-render as well. It’s a static image that’s high in quality and can be used in various applications like print, web, video, marketing materials, and so on. 

Typically, it involves generating an image in one to 60 minutes, depending on the application you’re using. Offline rendering also uses additional maps beyond PBR, which can include effects such as glossiness, specular displacement, IOR, subsurface scattering, and other elements that add to the realism of your render. Offline rendering also has higher lighting fidelity, so you have more control over shadows and more complex lighting rigs.

The benefits of real-time vs. offline rendering

There are two different key use cases for real-time versus offline rendering. If you’re looking to really engage with the content and to explore products from a variety of angles, real-time rendering is usually best. It’s ideal for creating interactive experiences, which can improve the customer experience when using a website to purchase products. 

If all you need to do is create multiple models, only changing things like material and color, you could use real-time rendering. However, if you’re planning to put those renders into a catalog or marketing shots, offline rendering would work perfectly well. 

The important thing is to consider what you need the render to do, which can help you narrow down the right solution for you. There’s no right or wrong answer, Yazan says, but you should ask yourself the purpose of the visual. Is it a design decision? A merchandising decision? A consumer-led decision? Do you need to see the product from multiple angles? This will help brands decide on which route to go down. 

The biggest challenge when implementing real-time rendering

If real-time rendering is the future, why aren’t more brands using it? While bigger brands in the fashion world can and do use it, for smaller brands it’s more challenging to get started because of the hardware requirements.

For real-time rendering, you may need a desktop application and a dedicated powerful GPU to run the necessary applications. This may not be a problem for all brands, but many clients are still using mobile phones, laptops, and pixel streaming to render products. 

If brands struggle to get the resources to perform real-time rendering, an alternative is to use videos to showcase the materials and make the customer experience more interactive.

Another challenge is rendering material like fur because there’s no standard way to capture or scan it. However, the beauty of PBR is that you can use it in multiple different engines, and it can introduce standardized definitions of things like metallic surfaces, material roughness, and the width of materials. 

Every single engine, whether it’s Blender or KeyShot, has a distinct way of describing things but none of them have a way of capturing specific materials. This means it’s often down to the technical skill of the person driving that specific engine. 


How brands can decide which type of rendering to use 

To help brands make better decisions, Anna says you should be asking these three questions:

·       What’s the use for 3D assets – real-time or offline rendering?
·       Do you have a content library to support it?
·       Do you understand the requirements and limitations of each platform?

This will help you decide which type of rendering is right for you and which is more achievable based on your current content library. 

For Yazan, step one for brands is to go through the entire process, grab a high-fidelity, quality 3D asset that they can generate, and apply offline rendering first, then look at real-time rendering. 

Along that process, make notes on which points you need visual feedback to make decisions, and then plug those in and see which ones make the most sense. This will allow you to understand which aspects of the render you and your customers will find most valuable. 

You may decide that you don’t really need interactive aspects on this particular item, but you really want to prioritize high fidelity instead. In this case, you could choose offline rendering instead and decide to focus on improving asset fidelity in your pipeline.

Once you’ve decided on that, you can start using tools like Swatchbook or VNTANA to help you optimize this further.


The future of 3D rendering 

Both Anna and Yazan believe that while there’s definitely still a place for offline rendering, real-time rendering is the future. The hope for the future is that we will see more real-time 3D assets in the industry as standard due to the greater fidelity and interactivity of real-time rendering. As more brands move toward this, Anna believes that this will set higher standards for real-time in the future. 

Another good thing about real-time rendering that Anna points out is backward compatibility. With real-time rendering, you can always create offline 3D assets from that, but you can’t do it the other way round. So, it makes sense for brands to focus on real-time rendering in the future.

Yazan also thinks that the apparel industry could learn a lot from the gaming industry when it comes to increasing the level of detail on 3D assets. The gaming industry has been working with 3D for a lot longer and we can take the lessons from that industry and apply them to fashion. 

With the increase in demand and usage of technology like virtual try-ons in fashion, the industry is clearly moving towards developing a more interactive experience for customers and real-time rendering will be key to this. Over time, the quality of the lighting, material, raytracing functionalities, real-time simulations, and so on will improve and become the norm. It’s just a matter of when, not if. 

To learn more about the use cases and future of real-time rendering, watch the full video with Yazan, Richard, and Anna today.