What is ray casting?

Introduction to ray casting.

Ray casting is a method for determining how light will hit the eye (or camera) in a virtual scene. With 3D graphics, ray casting mimics sending digital beams of light from the viewer’s perspective into the digital environment. The rays will intersect with objects in the scene and, based on where the intersections occur and the properties of each object, ray casting helps you to determine the colour and brightness of the pixels on the screen.

Ray casting is critical for rendering and visualisation because it creates realistic lighting. This technique simulates how light interacts with objects in the real world in a digital environment, which allows for astonishingly realistic characters, objects and scenes.

History of ray casting.

Ray casting is a fundamental technique for modern 3D design, but the technology is decades old. In the 1960s, computer scientists explored methods to simulate how light interacts with surfaces for realistic image generation. In the 1980s, Turner Whitted wrote a paper on recursive ray tracing that popularised the technique. It introduced the concept of handling reflections and refractions by recursively casting rays — a true game-changer for ray casting.

John Carmack popularised ray casting in the early 1990s with the game “Wolfenstein 3D,” which used ray casting to create a 3D perspective in a 2D world. In the 2000s, ray casting techniques blended with rasterisation to support real-time rendering in digital simulations. Today, companies are developing hardware-accelerated ray tracing, which pushes the boundaries of what’s possible.

Real-world applications.

Ray casting is great for video games, but it also has other important applications, such as:

1. Medical imaging. Ray casting renders volumetric data from CT and MRI scans. This gives medical professionals detailed 3D images that improve diagnostic accuracy.
2. Architectural visualisations. Architects use ray casting to predict how light will interact with their spaces. It’s especially useful for determining how sunlight will illuminate rooms at different times of the day or year.
3. Virtual reality (VR). VR uses ray casting for interaction detection, including gaze tracking and object selection. This creates a more immersive user experience.
4. Games. Ray casting is important for video game design because it supports realistic, interactive environments. Video games use ray casting for various purposes, including rendering and collision detection. Games like Doom Eternal and Cyberpunk 2077 are just a few examples of ray casting at work.

Volumetric ray casting.

Volumetric ray casting goes a step beyond standard ray casting. This technique uses volumetric data, such as 3D textures and datasets. Standard ray casting intersects rays with surfaces, while volumetric ray casting samples data throughout the space. This is useful in applications like medical imaging, where the model visualises 3D data from CT or MRI scans.

Ray casting vs. other rendering techniques.

Adobe Substance 3D is a creative suite for generating, modifying and stylising 3D models. Ray casting is a big part of Substance 3D, which helps with texture baking or how light interacts with digital materials. In addition to Substance 3D’s suite of 3D tools, ray casting makes it possible to create detailed, accurate textures for highly realistic 3D models.

Let’s take a look at how ray casting compares to other rendering techniques:

1. Ray casting. This method determines visibility by casting rays from the viewer and into the scene.
2. Rasterisation. This 3D modelling technique converts geometric shapes into pixels for display. This is widely used in real-time graphics for video games.
3. Ray tracing. This is an advanced form of ray casting. It simulates the path of rays of light as they travel through a scene. Ray tracing creates highly realistic images, but it has a steep computational cost.

Getting started with ray casting.

Here’s a quick guide to how you can get started with ray casting:

1. Understand the basics. Learn what rays are and how they work, as well as how they intersect with objects in a scene.
2. Start with simple scenes. If you’re just starting out, begin with basic shapes like spheres and planes. Use simple shading techniques to give depth to these objects. You’ll see how these choices affect shadows, reflections and refractions in the scene.
3. Expand to complex scenes. Once you’ve got that down, incorporate more objects and materials.

While this will help you to get started, don’t forget to continue investing in your ray casting skills. Online tutorials, communities and guides from Adobe Substance 3D will enhance your skills over time.

Experience the difference: ray casting with Adobe Substance.

Ray casting creates more realistic digital scenes by mimicking real-world lighting in digital spaces. From medical imaging to video games, ray casting brings reality to the digital era. Build your own stunning visuals: experiment with ray casting in Adobe Substance 3D now.