A general framework for pearlescent materials

Abstract

The unique and visually mesmerizing appearance of pearlescent materials has made them an indispensable ingredient in a diverse array of applications including packaging, ceramics, printing, and cosmetics. In contrast to their natural counterparts, such synthetic examples of pearlescence are created by dispersing microscopic interference pigments within a dielectric resin. The resulting space of materials comprises an enormous range of different phenomena ranging from smooth lustrous appearance reminiscent of pearl to highly directional metallic gloss, along with a gradual change in color that depends on the angle of observation and illumination. All of these properties arise due to a complex optical process involving multiple scattering from platelets characterized by wave-optical interference. This article introduces a flexible model for simulating the optics of such pearlescent 3D microstructures. Following a thorough review of the properties of currently used pigments and manufacturing-related effects that influence pearlescence, we propose a new model which expands the range of appearance that can be represented, and closely reproduces the behavior of measured materials, as we show in our comparisons. Using our model, we conduct a systematic study of the parameter space and its relationship to different aspects of pearlescent appearance. We observe that several previously ignored parameters have a substantial impact on the material's optical behavior, including the multi-layered nature of modern interference pigments, correlations in the orientation of pigment particles, and variability in their properties (e.g. thickness). The utility of a general model for pearlescence extends far beyond computer graphics: inverse and differentiable approaches to rendering are increasingly used to disentangle the physics of scattering from real-world observations. Our approach could inform such reconstructions to enable the predictive design of tailored pearlescent materials.

SpongeCake: A Layered Microflake Surface Appearance Model

“…This work was later improved by Xia et al [2020] and Gamboa et al [2020] with more advanced sampling approaches and more eicient estimators. Guillén et al [2020] leverage the generality of position-free MC for modeling pearlescent pigments. Though fairly eicient and versatile, these methods produce Monte Carlo noise (variance), and still cannot compete with analytic solutions in terms of performance.…”

“…The microlake model is successful in representing ibers and fabrics [Zhao et al 2011]. Other work has also beneited from using microlakes for representing other types of materials such as foliage [Loubet and Neyret 2018], or special pigments [Guillén et al 2020]. Heitz et al [2015] introduced a versatile representation named symmetric GGX (SGGX) to eiciently describe microlake distributions using 3× 3 positive-deinite matrices, allowing for surface-like and iber-like microlakes, including convenient control over their orientations.…”

SpongeCake: A Layered Microflake Surface Appearance Model

“…This work was later improved by Xia et al [2020] and Gamboa et al [2020] with more advanced sampling approaches and more efficient estimators. Guillén et al [2020] leverages the generality of position-free MC for modeling pearlescent pigments. Though fairly efficient and versatile, these methods cause Monte Carlo noise (variance), and still cannot compete with analytic solutions in terms of performance.…”

“…The microflake model is successful in representing fibers and fabrics [Zhao et al 2011]. Other work has also benefited from using microflakes for representing other types of materials such as foliage [Loubet and Neyret 2018], or special pigments [Guillén et al 2020]. Heitz et al [2015] introduced a versatile representation named symmetric GGX (SGGX) to efficiently describe microflake distributions using 3× 3 positive-definite matrices, allowing for surface-like and fiber-like microflakes, including convenient control over their orientations.…”

Çok Katmanlı Malzemelerde Açısal Renk Değişimleri ve Işıltı Etkilerinin Analizi

“…However, they are computationally more expensive due to the measurement costs. Guillen et al [14] proposed a spectral BSDF model with an extension in parameters (substrate thickness). This extension resulted in an improvement in terms of accuracy.…”