4K4D: The AI Breakthrough Enhancing Immersive Experiences 30x Faster

Oct 26, 2023

Blog Post image titled: "4K4D: The AI Breakthrough Enhancing Immersive Experiences 30x Faster"


This paper from Zhejiang University, Image Derivitave Inc and Ant Group introduces a new method called 4K4D that can create highly realistic videos of dynamic 3D scenes, like people moving around, in real-time at very high 4K resolution. 

Currently, methods that can render high quality dynamic 3D scenes are very slow, taking minutes to generate a single frame. This makes them impractical for applications like virtual reality. 

The key innovation of 4K4D is representing the 3D scene as a "point cloud" - a collection of points in 3D space that each have attributes like color, density, etc. The movement and appearance of the points over time are encoded using neural networks. It’s a fascinating use of networks to produce imagery in a much faster way! 

During rendering, the point cloud is processed in a novel way called "differentiable depth peeling" that allows leveraging graphics hardware acceleration to achieve extremely fast rendering speeds of over 200 frames per second at 1080p resolution.


Some technical details:


- The point cloud is regularized using a "4D feature grid" which makes optimization more robust

- A hybrid appearance model is used combining image-based rendering and spherical harmonics lighting for high quality

- The rendering method is fully differentiable, allowing end-to-end training from input videos


Because 4K4D can render high fidelity 3D content faster than previous methods by over 30X, it has many potential applications:


- VR/AR - Immersive real-time experiences require rendering speeds >90 FPS which is now possible

- Sports broadcasting - Smooth 4K 3D replay rendering can enhance coverage with  photorealistic interactive replays. Viewers could control the camera angle or zoom on replays to better analyze key moments in the game from any perspective.

- Digital human animation - Realistic human models can be rendered interactively for games/movies

- Telepresence - Life-like avatars reconstructed from video can enable remote communication


In summary, 4K4D enables photorealistic 4K rendering of dynamic 3D scenes in real-time, unlocking many new opportunities across industries from entertainment to communications. The work represents an important step towards interactive and immersive 3D experiences.


We’re huge fans of films and see that 4K4D could enable several new capabilities:


- Photoreal digital actors - With real-time 4K rendering of humans from video, digital actors could be created and interacted with during filming, opening new creative possibilities. With the recent Writers’ and Actors’ strikes this may not be the most wanted use of the technology by these groups. However, it still has to be mentioned. 


- Enhanced previsualization - Directors could preview complex CG scenes at high visual fidelity in real-time to iterate and plan shots. Saving time could help production costs.


- Immersive VR/AR experiences - Filmed scenes reconstructed with 4K4D could allow VR/AR experiences with greater sense of presence and interaction. Imagine being much more involved in the movies your watching thanks to such experiences this could bring. 


We also believe that AI in retail has huge opportunities! Some potential ways this 4K4D technology could be applied are:


- Virtual try-on - 4K4D human models tailored to shoppers could allow realistic virtual try-on of clothing and accessories. There’s already mirrors like this, but could this help with online shopping and reducing returns? 


- Lifelike product visualization - Photoreal visualization of products in any environment can better convey their features online.


- Immersive virtual storefronts - Reconstructing real stores digitally can enable interactive virtual shopping experiences.


On the Ethics side, like many AI advances, 4K4D raises some concerns:


- Consent - Reconstructing and reusing likenesses of people digitally should only be done with consent.

- Bias - Diverse training data must be used so capabilities work equally well for all people.

- Misuse potential - Realistic synthesis of images/video could potentially enable new forms of misinformation. Proactive mitigation is needed.

- Accessibility - The benefits should be made accessible to people across income levels and abilities.


Overall, 4K4D is an exciting breakthrough, but its development and applications should thoughtfully account for social impacts. With a human-centric approach, it can enable many new possibilities across sectors.




This paper from Zhejiang University, Image Derivitave Inc and Ant Group introduces a new method called 4K4D that can create highly realistic videos of dynamic 3D scenes, like people moving around, in real-time at very high 4K resolution. 

Currently, methods that can render high quality dynamic 3D scenes are very slow, taking minutes to generate a single frame. This makes them impractical for applications like virtual reality. 

The key innovation of 4K4D is representing the 3D scene as a "point cloud" - a collection of points in 3D space that each have attributes like color, density, etc. The movement and appearance of the points over time are encoded using neural networks. It’s a fascinating use of networks to produce imagery in a much faster way! 

During rendering, the point cloud is processed in a novel way called "differentiable depth peeling" that allows leveraging graphics hardware acceleration to achieve extremely fast rendering speeds of over 200 frames per second at 1080p resolution.


Some technical details:


- The point cloud is regularized using a "4D feature grid" which makes optimization more robust

- A hybrid appearance model is used combining image-based rendering and spherical harmonics lighting for high quality

- The rendering method is fully differentiable, allowing end-to-end training from input videos


Because 4K4D can render high fidelity 3D content faster than previous methods by over 30X, it has many potential applications:


- VR/AR - Immersive real-time experiences require rendering speeds >90 FPS which is now possible

- Sports broadcasting - Smooth 4K 3D replay rendering can enhance coverage with  photorealistic interactive replays. Viewers could control the camera angle or zoom on replays to better analyze key moments in the game from any perspective.

- Digital human animation - Realistic human models can be rendered interactively for games/movies

- Telepresence - Life-like avatars reconstructed from video can enable remote communication


In summary, 4K4D enables photorealistic 4K rendering of dynamic 3D scenes in real-time, unlocking many new opportunities across industries from entertainment to communications. The work represents an important step towards interactive and immersive 3D experiences.


We’re huge fans of films and see that 4K4D could enable several new capabilities:


- Photoreal digital actors - With real-time 4K rendering of humans from video, digital actors could be created and interacted with during filming, opening new creative possibilities. With the recent Writers’ and Actors’ strikes this may not be the most wanted use of the technology by these groups. However, it still has to be mentioned. 


- Enhanced previsualization - Directors could preview complex CG scenes at high visual fidelity in real-time to iterate and plan shots. Saving time could help production costs.


- Immersive VR/AR experiences - Filmed scenes reconstructed with 4K4D could allow VR/AR experiences with greater sense of presence and interaction. Imagine being much more involved in the movies your watching thanks to such experiences this could bring. 


We also believe that AI in retail has huge opportunities! Some potential ways this 4K4D technology could be applied are:


- Virtual try-on - 4K4D human models tailored to shoppers could allow realistic virtual try-on of clothing and accessories. There’s already mirrors like this, but could this help with online shopping and reducing returns? 


- Lifelike product visualization - Photoreal visualization of products in any environment can better convey their features online.


- Immersive virtual storefronts - Reconstructing real stores digitally can enable interactive virtual shopping experiences.


On the Ethics side, like many AI advances, 4K4D raises some concerns:


- Consent - Reconstructing and reusing likenesses of people digitally should only be done with consent.

- Bias - Diverse training data must be used so capabilities work equally well for all people.

- Misuse potential - Realistic synthesis of images/video could potentially enable new forms of misinformation. Proactive mitigation is needed.

- Accessibility - The benefits should be made accessible to people across income levels and abilities.


Overall, 4K4D is an exciting breakthrough, but its development and applications should thoughtfully account for social impacts. With a human-centric approach, it can enable many new possibilities across sectors.