Ray tracing

Ray tracing sends a ray from the camera through each pixel and finds the surface it hits. At that point the renderer checks whether the surface can see the lights, whether it reflects like a mirror or transmits like glass, and fires new rays where needed. The result is crisp reflections, refraction and accurate shadows.

Ray tracing versus path tracing

Classic ray tracing excels at reflections, refraction and direct-light shadows. Path tracing extends the same idea, following light as it bounces between surfaces many times using random samples, so it also captures indirect light, colour bleeding and soft shadows in a physically based way. In everyday speech, “ray tracing” is often used for the whole family.

Its role in architectural rendering

Glass facades, polished floors, metal trims and water simply do not look right without it. Once limited to offline renderers, the technique has reached real-time engines thanks to graphics cards with hardware support. More rays still mean longer render times. The balance between quality and speed is set through controls such as sample counts and bounce limits, and a well-built scene raises them only where they are really needed.