Information
- Publication Type: Technical Report
- Workgroup(s)/Project(s): not specified
- Date: July 1998
- Number: TR-186-2-98-17
- Keywords: importance sampling, albedo function, BRDF representation, Reflectance function
Abstract
The paper presents new, simple and physically
plausible, but not physically based reflectance models for
metals and other specular materials. The
most important member of this family is the modification
of the Phong model, which can eliminate its
non-metallic characteristics. The new model gives back the
ideal mirror in
the limit case, is easier to compute than other known models
and is particularly suitable for importance sampling to
efficiently generate reflected directions
in Monte-Carlo ray-tracing algorithms.
Due to its simplicity, the new
model can become an integral part of commercial CAD systems to
describe the specular part or metallic behavior.
The paper also examines the energy balance of the previously
known and the newly proposed BRDFs concentrating on the behavior
at grazing angles, and comes to the conclusion that the Ward and
the Cook-Torrance models cannot guarantee energy balance and thus
are not physically plausible. Finally, the generated images
demonstrate how the metallic impression can be provided by the
new models.
Additional Files and Images
Weblinks
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BibTeX
@techreport{Szir-1998-Ref,
title = "New Simple Reflectance Models for Metals and other Specular
Materia ls",
author = "L\'{a}szl\'{o} Neumann and Attila Neumann and L\'{a}szl\'{o}
Szirmay-Kalos",
year = "1998",
abstract = "The paper presents new, simple and physically plausible, but
not physically based reflectance models for metals and other
specular materials. The most important member of this family
is the modification of the Phong model, which can eliminate
its non-metallic characteristics. The new model gives back
the ideal mirror in the limit case, is easier to compute
than other known models and is particularly suitable for
importance sampling to efficiently generate reflected
directions in Monte-Carlo ray-tracing algorithms. Due to its
simplicity, the new model can become an integral part of
commercial CAD systems to describe the specular part or
metallic behavior. The paper also examines the energy
balance of the previously known and the newly proposed BRDFs
concentrating on the behavior at grazing angles, and comes
to the conclusion that the Ward and the Cook-Torrance models
cannot guarantee energy balance and thus are not physically
plausible. Finally, the generated images demonstrate how the
metallic impression can be provided by the new models.",
month = jul,
number = "TR-186-2-98-17",
address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria",
institution = "Institute of Computer Graphics and Algorithms, Vienna
University of Technology ",
note = "human contact: technical-report@cg.tuwien.ac.at",
keywords = "importance sampling, albedo function, BRDF representation,
Reflectance function",
URL = "https://www.cg.tuwien.ac.at/research/publications/1998/Szir-1998-Ref/",
}