@MASTERSTHESIS\{IMM2013-06645,
    author       = "V. Mihaylov",
    title        = "Rendering Metals and Worn or Weathered Metallic Objects",
    year         = "2013",
    school       = "Technical University of Denmark, Department of Applied Mathematics and Computer Science / {DTU} Co",
    address      = "Matematiktorvet, Building 303B, {DK-}2800 Kgs. Lyngby, Denmark, compute@compute.dtu.dk",
    type         = "",
    note         = "{DTU} supervisor: Jeppe Revall Frisvad, jerf@dtu.dk, {DTU} Compute",
    url          = "http://www.compute.dtu.dk/English.aspx",
    abstract     = "This thesis focuses on computer generated visualization of metal material objects. There are two basic rendering approaches that have been taken into account in the scope of this project: ray traced rendering approach using NVidia’s MentalRay render engine, and a real-time rendering approach using Unity3D game engine. In both cases the goal of the thesis was to find and implement an effective solution to simulate a metal material surface. In ray traced rendering as well as real-time rendering, a physically-based light reflectance model has been used to simulate as accurately as possible the interaction between the light coming from the light source and the object’s surface. That interaction is crucial to the appearance of the object.
Once the metal material simulation has been achieved, the thesis focuses on simulation of weathering and aging effects on metallic surfaces. Techniques for simulating physical damage on surfaces such as scratches, cavities, and grooves are discussed for both ray tracing and real-time rendering approach. The project focuses on the simulation of some non-physical damages on metal surfaces that are due to environmental and weathering conditions. Simulation of metal corrosion resulting in iron oxide (red rust) has been covered. The rusty surface has been simulated with a physically-based light reflectance model designed to simulate rough surfaces. The thesis covers the development and implementation of a system for simulating the life span of a patina formation and development process. The system does not take any physically accurate input into consideration when simulating patina formations for specific time period (i.e. 1 month, 5 years) but instead uses user-defined colors and procedurally generated noise textures to simulate the spread and color of the metallic patina."
}