01Overview
In 1968 Appel proposed ray casting; in 1980 Whitted added recursive ray tracing for reflection and refraction. In 1984 radiosity modelled diffuse light with energy conservation; in 1986 the Reyes pipeline rendered efficiently with micropolygons and became the basis of the film industry.
Real-time rendering long relied on rasterisation: project triangles onto the screen and shade each pixel. In 2018 NVIDIA’s RTX brought hardware ray tracing to consumer GPUs, and hybrid rendering became the norm. Meanwhile neural rendering — NeRF, 3D Gaussian splatting — rebuilds scenes from learnable representations, blurring graphics and vision.
02History
- 1980
Whitted ray tracing
Recursive reflection and refraction.
- 1984
Radiosity
An energy method for global illumination.
- 1986
The Reyes pipeline
Film-grade micropolygon rendering.
- 2018
Real-time ray tracing
RTX hardware.
- 2020
NeRF
Neural radiance fields reconstruct a scene.
03Core concepts
Rasterisation
Project geometric primitives onto pixels; good for real time.
Ray tracing
Cast rays from the camera to simulate reflection, refraction and shadow.
Global illumination
Account for light bouncing repeatedly through the scene.
04Hands-on
Do it once — it beats reading it ten times
Render the same scene with a rasteriser and a ray tracer; compare time and one visual artefact each
05Self-check
Say it in your own words first, then open the answer. Whatever you cannot explain is what to review next.
Can you explain "Rasterisation"?
Project geometric primitives onto pixels; good for real time.
Can you explain "Ray tracing"?
Cast rays from the camera to simulate reflection, refraction and shadow.
Can you explain "Global illumination"?
Account for light bouncing repeatedly through the scene.
What problem did it solve, and why was there nothing better at the time?
Go back to the history section: how was this done before, and what did it cost?
If you had to build it today, how would you break it down?
Use the hands-on task above: write a plan of at most three steps before you start.
06Key people
Turner Whitted
1943 –
Proposed recursive ray tracing.
Ed Catmull
1945 –
Pixar co-founder; a driving force behind RenderMan and Reyes.
07Further reading
- Computer Graphics: Principles and Practice
- Real-Time Rendering