In movies, video games, virtual reality environments, 3D configurators and other computer graphics arenas, lighting is the key to accurate representations of our physical world. The calculation of real-looking lighting remains complex and inefficient because the need to consider all possible paths light can take remains too costly for each pixel in real time.

calculation methods

Computer scientists from Aalto University in Otaniemi, Finland, with expertise in the development of video games and lighting simulation algorithms, have developed a new calculation method to meet this key challenge. Developed by Ari Silvennoinen, a PhD student in Computer Science, and Professor Jaako Lehtinen, the method enables real-time lighting simulations that are much faster and more accurate than existing methods. They focus on the calculation of realistic indirect lighting from dynamic light sources in mostly static scenes and show the accuracy of their algorithm in multiple scenes where ambient lighting consists of complicated light and shadow patterns.

Silvennoinen and Lehtinen, both researchers at Remedy and Nvidia respectively, will present their research at SIGGRAPH Asia 2017 in Bangkok from 27 November to 30 November. The annual conference and exhibition presents the world’s leading professionals, scientists and creative minds at the forefront of computer graphics and interactive techniques.

“Dynamic real-time global illumination remains a major challenge in this field. The challenge is that in a scene, any two points in the scene can interact by participating in the easy transport of each other,” explains Silvennoinen. “The number of these interactions is increasing very rapidly. For example, with only 1,000 points, we potentially have 1,000,000,000 interactions.

The most important novel contribution is a technique that accurately calculates indirect lighting using information from only a very sparse set of Radiance Sonbes samples that capture scene lighting at a single point, enabling real-time operation in complex 3D scenes at eye level with modern games.

“The quality of the results, especially the indirect shadows, is very high because we are very careful about the visibility between the transmitters and receivers,” says Silvennoinen. “Our method generates high quality indirect lighting and makes it practical”.

In the study, the researchers demonstrate their method with architectural illustrations and show exactly how, for example, light moves through a window in a living room over time or through shady columns of a dimly lit palace.

In addition to applying it directly to game graphics, the researchers are introducing this method so that architects and their customers can see how their designs work with dynamic lighting. Future work could also enable lighting designers to get instant feedback while placing virtual light sources in computationally constrained environments such as virtual or augmented reality.

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