How Real-Time Ray Tracing will Change Architectural Visualization

What is Real-Time Ray Tracing?

Real-time ray tracing is a rendering technique that can simulate how light rays interact with different surfaces and materials in a 3D scene. Ray tracing has been used for decades to create highly realistic computer generated imagery in fields like film production and architectural visualization. However, rendering a scene with ray tracing has traditionally been very computationally expensive. Real-time ray tracing uses advanced GPU hardware acceleration to allow ray traced scenes to be rendered interactively in real-time.

Some key advantages of real-time ray tracing include:

• Accurate simulation of light behavior like reflections, refractions, shadows, global illumination and ambient occlusion. This leads to much more realistic lighting and materials.
• Ability to interactively edit scenes and camera positions and instantly see the results. This enables new workflows for designers and artists.
• Good scalability across multiple GPUs allows for high resolution imagery and complex scenes.

Why Real-Time Ray Tracing Matters for Architectural Visualization

Architectural visualization relies on advanced 3D rendering techniques to create immersive visuals of architectural designs. These visualizations help architects pitch their designs to clients. Real-time ray tracing is set to revolutionize architectural visualization by enabling unprecedented realism as well as new interactive and iterative workflows.

Enables Photorealistic Rendering

Ray tracing accurately simulates the physical behavior of light. Effects like reflections, refractions and global illumination are challenging to approximate using traditional rendering techniques like rasterization. Real-time ray tracing makes it possible to interactively render photorealistic architectural visuals which accurately portray material qualities and lighting conditions. This level of realism better communicates the design intent.

Faster Iteration and Interactive Workflows

Traditionally, architectural renderings could take hours or days to fully render a scene. Real-time ray tracing enables users to interactively refine the camera, lighting, materials and environment and instantly see the results. This makes it faster to iterate on visualizations and reduces the time required to create compelling architectural visualizations.

Scalable Performance

Ray tracing scales well across multiple GPUs and takes advantage of hardware acceleration. This allows users to render high resolution photorealistic visuals and richly detailed scenes with many light sources and objects. Real-time performance also facilitates new applications like virtual reality.

Easier Visualization of Design Changes

Real-time ray traced renderings better communicate the look and feel of the final built structure. This visual fidelity helps architects, interior designers and stakeholders visualize and evaluate design changes like materials, lighting and layouts interactively. This can influence design decisions and reduce costly late stage changes.

Comparative Analysis of Real-Time Ray Tracing and Rasterization

Real-time ray tracing offers some clear advantages over previous rendering techniques like rasterization for architectural visualization:

| Rendering Method | Real-Time Ray Tracing | Rasterization |
|-|-|-|
| Lighting Accuracy | Very high – Simulates light behavior | Approximate – Use tricks like shadow maps and screen-space effects |
| Material Realism | Excellent – Complex material models with global illumination | Limited – Rely on texture maps and approximate lighting |
| Iterative Workflow | Interactive – Instantly see any design changes | Slow – Requires re-rendering scene |
| Performance Scalability | Excellent – Leverages GPU acceleration | Limited – Runs primarily on CPU |
| Ease of Use | High – Less need for ‘tricks’ to optimize lighting | Moderate – Lighting is harder to tune |

Detailed Analysis

Ray tracing can accurately simulate the physical behavior of light using techniques like path tracing and photon mapping. Effects like reflections, refractions, caustics and global illumination are integral to the algorithm. This means visuals have much more realistic lighting with natural shadows, reflections and ambient occlusion.

In contrast, rasterization relies on approximate lighting effects like shadow maps and screen space ambient occlusion. These can often look artificial on close inspection. Rasterization also requires texture maps to simulate complex materials whereas ray tracing can simulate material response directly.

For iterative workflows, ray tracing enables users to interactively edit a 3D scene while instantly viewing photorealistic results. Rasterization requires iterative re-rendering of the 3D scene which is considerably slower.

Ray tracing performance also scales well across multiple GPUs which allows rendering at resolutions like 8K with many light sources and reflections. Rasterization is mostly processed on the CPU currently and has limited scalability.

Finally, ray tracing with global illumination greatly simplifies lighting a 3D scene. Rasterization requires manually placing lights, tuning intensities and configuring ambient occlusion for realistic results.

Ray Tracing in Architectural Visualization Software

Most leading architectural visualization and 3D modelling software have added support for real-time ray tracing in recent years. Here are some examples:

Autodesk 3ds Max

The NVIDIA RTX renderer for 3ds Max brings accelerated real-time ray tracing to this popular 3D modelling and animation software. Key features include ray traced reflections, shadows, ambient occlusion and denoising.

Chaos Group V-Ray GPU

V-Ray GPU is a version of the V-Ray renderer optimized for NVIDIA RTX cards. It supports interactive rendering and advanced effects like subsurface scattering.

Blender Cycles

Cycles is Blender’s ray tracing based rendering engine. With supported GPUs, Cycles can provide an interactive preview mode for animations and models.

Unreal Engine

The Unreal Engine game development platform has robust support for real-time ray tracing which makes it suitable for architectural visualization. NVIDIA’s MDL material definition language is also natively supported.

Unity

Unity provides production-ready real-time ray tracing via its High Definition Render Pipeline. This allows Unity to target professional visualization applications.

The Future of Real-Time Ray Tracing

While ray tracing technology has existed for decades, the advent of real-time ray tracing marks an inflection point. Some future trends include:

• Expanding adoption – RTX accelerated ray tracing support will likely become ubiquitous in all visualization software. Real-time ray tracing for offline rendering is also being researched.

• Cloud rendering – Cloud GPU services like AWS EC2 allow anyone to access powerful real-time ray tracing resources on demand. The cloud could democratize photorealistic rendering.

• Simulations and physics – Ray tracing lends itself well to realistic simulations of lighting, acoustics and thermodynamics. Ray tracing may be used to simulate aspects of building performance and occupant behavior.

• Virtual and augmented reality – The performance and realism of ray tracing are ideal for creating immersive architectural experiences in VR and AR. Real-time ray tracing enables photorealistic previews of designs.

• Automation – Repeated tasks like lighting and material assignment can potentially be automated with machine learning trained on ray traced architectural visuals.

In summary, real-time ray tracing is set to become integral to the next generation of architectural visualization. The unprecedented realism, performance and flexibility afforded by ray tracing will enable more productive design workflows and unlock new possibilities for visualizing and interacting with architectural designs.