Real-time rendering

Real-time rendering redraws the scene the moment you move the camera. Familiar from video games, it relies mainly on the rasterization power of the graphics card to produce dozens of frames every second. Graphics cards with hardware ray tracing add more convincing reflections and shadows at that speed.

Why architects use it

The big advantage is speed of feedback. Change a material or slide the sun to a different hour and the result is there, with no waiting. In a client meeting you can walk through the model and compare options on the spot. Animations, virtual tours and VR experiences can also be produced in relatively little time.

Its limits

Speed comes at a price. Bounced light, soft shadows and complex glass reflections are usually handled with approximations compared with a path-traced image. The difference shows most in interiors and night scenes. Many studios use a real-time engine during design and a physically based engine for the final images; the two approaches complement each other more than they compete.

For an example of a tool in this category, see our article on Twinmotion’s real-time features.