= Modelling and Rendering Ice =

== Overview ==

We want to model a scene containing objects made out of ice.  Specifically, we hope to produce images similar to the ones below, where caustic effects and translucency is apparent.

http://www.stanford.edu/~myilang/cs348b/final/ice-cubes-1.jpg
http://www.stanford.edu/~myilang/cs348b/final/ice-cubes-2.jpg

== Previous Work ==

A previous CS 348B final project, [http://graphics.stanford.edu/courses/cs348b-competition/cs348b-03/ice/ Rene Patnode & Evan Parker], attempted to produce realistic looking ice and had some success.  They modelled the ice by defining a new material that had similar properties to ice.  To simulate a rough surface, they made use of bump maps.  However, their work fails to take into account the non-homogenous density of ice and the bump map fails to capture the important refraction happening near the surface (inside grooves for example).

== Our Proposal ==

Our project will more accurately render objects made of ice.

=== Caustics ===

This is mainly the result of light refracting and reflecting at the surface of ice.  We will be using a mesh for our models, and we will roughen the surface by adding noise consistent with that of ice.  Choosing a good noise model will be crucial in making the models look like they are made out of ice.  To produce the caustics, we plan to simply shoot rays at the surface to find out how light is refracted.


=== Non-homogenous Transparency ===

Ice has a lot of air bubbles inside which means that it has a non-constant density.  This means that light rays travelling through the solid has a chance to be reflected or refracted.  Even ice with a smooth surface often produce distorted images because of this effect.  Bernard & Ural have done some work in this respect by using Perlin noise to define the density of the object ini [http://delivery.acm.org/10.1145/1110000/1101414/p131-barnard.pdf?key1=1101414&key2=9620808411&coll=GUIDE&dl=acm&CFID=76289715&CFTOKEN=76657132 Rendering Translucency with Perlin Noise].  We will be making use of their research to implement the translucency of our ice.