One of the more advanced methods to do hair in games is presented in this paper. The following is the abstract:

“This thesis evaluates, improves and develops methods for generating, simulating and rendering hair in real-time. The purpose is finding techniques which make use of recent hardware to present an as good as possible visual result while keeping performance at such a level that integration into a game scene is viable. The Kajiya-Kay and Marschner lighting models for hair are evaluated, including recent resource saving discretizations to the Marschner model. Two shadowing methods are adapted and investigated for the nature of hair and real-time applications, and one new method is presented as a lower quality and faster alternative for translucent occluders. For dynamics, two models are developed and an existing model for simulating trees is adapted. The implementation uses and takes into account the capabilities and limits of modern graphics hardware, including various techniques that greatly reduces the amount of data sent to the graphics card. The implementation also includes a Maya pipeline for modeling hair. The result is a state-of-the-art rendering and simulation of hair for real-time game purposes.”

 

Link to the paper:
http://graphics.cs.lth.se/theses/projects/hair/

 A very advanced method to do grass rendering with dynamic lightning. There are shadows cast from each grass straw and you can paint a density map to select where you want grass and how much. The grass is obviously also animated in a very realistic way. The following is how they describe the technique briefly.

“We use a combination of geometry and lit volume slices, composed of Bidirectional Texture Functions (BTFs). BTFs, generated using a fast pre-computation step, provide an accurate, per pixel lighting of the grass.”

Link to more images and the paper:
http://www.kevinboulanger.net/grass.html

A method to create very realistic and convincing dynamic fluids in games. For example smoke and explosions.  

The abstract:

“In this paper we present a simple and rapid implementation of a fluid dynamics solver for game engines. Our tools can greatly enhance games by providing realistic fluid-like effects such as swirling smoke past a moving character. The potential applications are endless. Our algorithms are based on the physical equations of fluid flow, namely the Navier-Stokes equations. These equations are notoriously hard to solve when strict physical accuracy is of prime importance. Our solvers on the other hand are geared towards visual quality. Our emphasis is on stability  and speed, which means that our simulations can be advanced with arbitrary time steps. We also demonstrate that our solvers are easy to code by providing a complete C code implementation in this paper. Our algorithms run in real-time for reasonable grid sizes in both two and three dimensions on standard PC hardware, as demonstrated during the presentation of this paper at the conference.”

Link to the paper:
http://www.dgp.toronto.edu/people/stam/reality/Research/pdf/GDC03.pdf

This paper describes a technique to do both transitional blending between animations and layering of two animations. Layering is when two animations is run simultaneously and the result should be the combination of them. Transitional blending is the transition from one animation to another, for example running to idle animation.

A picture showing layering:

And a link to the paper:
http://graphics.cs.lth.se/theses/reports/jeppsson_masterthesis.pdf