@inproceedings{14241,
  abstract     = {We present a technique to optimize the reflectivity of a surface while preserving its overall shape. The naïve optimization of the mesh vertices using the gradients of reflectivity simulations results in undesirable distortion. In contrast, our robust formulation optimizes the surface normal as an independent variable that bridges the reflectivity term with differential rendering, and the regularization term with as-rigid-as-possible elastic energy. We further adaptively subdivide the input mesh to improve the convergence. Consequently, our method can minimize the retroreflectivity of a wide range of input shapes, resulting in sharply creased shapes ubiquitous among stealth aircraft and Sci-Fi vehicles. Furthermore, by changing the reward for the direction of the outgoing light directions, our method can be applied to other reflectivity design tasks, such as the optimization of architectural walls to concentrate light in a specific region. We have tested the proposed method using light-transport simulations and real-world 3D-printed objects.},
  author       = {Tojo, Kenji and Shamir, Ariel and Bickel, Bernd and Umetani, Nobuyuki},
  booktitle    = {SIGGRAPH 2023 Conference Proceedings},
  isbn         = {9798400701597},
  location     = {Los Angeles, CA, United States},
  publisher    = {Association for Computing Machinery},
  title        = {{Stealth shaper: Reflectivity optimization as surface stylization}},
  doi          = {10.1145/3588432.3591542},
  year         = {2023},
}

@inproceedings{12979,
  abstract     = {Color and gloss are fundamental aspects of surface appearance. State-of-the-art fabrication techniques can manipulate both properties of the printed 3D objects. However, in the context of appearance reproduction, perceptual aspects of color and gloss are usually handled separately, even though previous perceptual studies suggest their interaction. Our work is motivated by previous studies demonstrating a perceived color shift due to a change in the object's gloss, i.e., two samples with the same color but different surface gloss appear as they have different colors. In this paper, we conduct new experiments which support this observation and provide insights into the magnitude and direction of the perceived color change. We use the observations as guidance to design a new method that estimates and corrects the color shift enabling the fabrication of objects with the same perceived color but different surface gloss. We formulate the problem as an optimization procedure solved using differentiable rendering. We evaluate the effectiveness of our method in perceptual experiments with 3D objects fabricated using a multi-material 3D printer and demonstrate potential applications. },
  author       = {Condor, Jorge and Piovarci, Michael and Bickel, Bernd and Didyk, Piotr},
  booktitle    = {SIGGRAPH ’23 Conference Proceedings},
  isbn         = {9798400701597},
  keywords     = {color, gloss, perception, color compensation, color management},
  location     = {Los Angeles, CA, United States},
  publisher    = {Association for Computing Machinery},
  title        = {{Gloss-aware color correction for 3D printing}},
  doi          = {10.1145/3588432.3591546},
  year         = {2023},
}