Bilkent University
Department of Computer Engineering


Physically-Based Shading Model for Weather effects in Virtual Environments


Nail Akıncı
MSc Student
Computer Engineering Department
Bilkent University

Existing real-time weather effects that are currently used in games and virtual reality applications are simple particle based snow and rain effects. Therefore, weather effects in real-time environments can be regarded as subtle when compared to real life with extreme weather circumstances, now there is so much more space to improve, because of fast developing GPU technology, there is enough GPU power to use advanced weather effects in virtual environments, with little cost.

Advanced Effects like accumulation of snow and rain with respect to topology and world space normal of the surface can really change the appearance of the virtual environment drastically just like in real life. Also effect of the wind and direction of the sun is actually underestimated in many virtual environments.

In real-life, snow and rain does not change the actual object, and it is a temporary effect. Therefore, it can be seen as a post-process effect, and so actual objects and materials do not change in real life. Thus, it is possible to make system that does not affect the creation of the environment, so that user only creates environment for summer, and all imported assets in the scene, automatically updates with respect to weather change.

In our system, we use Physically-based shading model, and snow effect is just a post-process calculation that does not change the actual shader. By just adding extra properties to shaders and using tessellation, extreme weather effects and dynamic change in weather is possible, without extra work for artists.


DATE: 30 March, 2015, Monday @ 15:40