---
_id: '14241'
abstract:
- lang: eng
  text: 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.
acknowledgement: "The authors would like to thank Yuki Koyama and Takeo Igarashi for
  early discussions, and Yuta Yaguchi for support in 3D printing. This research is
  partially supported by the Israel Science Foundation grant number 1390/19.\r\n"
article_number: '20'
article_processing_charge: No
arxiv: 1
author:
- first_name: Kenji
  full_name: Tojo, Kenji
  last_name: Tojo
- first_name: Ariel
  full_name: Shamir, Ariel
  last_name: Shamir
- first_name: Bernd
  full_name: Bickel, Bernd
  id: 49876194-F248-11E8-B48F-1D18A9856A87
  last_name: Bickel
  orcid: 0000-0001-6511-9385
- first_name: Nobuyuki
  full_name: Umetani, Nobuyuki
  last_name: Umetani
citation:
  ama: 'Tojo K, Shamir A, Bickel B, Umetani N. Stealth shaper: Reflectivity optimization
    as surface stylization. In: <i>SIGGRAPH 2023 Conference Proceedings</i>. Association
    for Computing Machinery; 2023. doi:<a href="https://doi.org/10.1145/3588432.3591542">10.1145/3588432.3591542</a>'
  apa: 'Tojo, K., Shamir, A., Bickel, B., &#38; Umetani, N. (2023). Stealth shaper:
    Reflectivity optimization as surface stylization. In <i>SIGGRAPH 2023 Conference
    Proceedings</i>. Los Angeles, CA, United States: Association for Computing Machinery.
    <a href="https://doi.org/10.1145/3588432.3591542">https://doi.org/10.1145/3588432.3591542</a>'
  chicago: 'Tojo, Kenji, Ariel Shamir, Bernd Bickel, and Nobuyuki Umetani. “Stealth
    Shaper: Reflectivity Optimization as Surface Stylization.” In <i>SIGGRAPH 2023
    Conference Proceedings</i>. Association for Computing Machinery, 2023. <a href="https://doi.org/10.1145/3588432.3591542">https://doi.org/10.1145/3588432.3591542</a>.'
  ieee: 'K. Tojo, A. Shamir, B. Bickel, and N. Umetani, “Stealth shaper: Reflectivity
    optimization as surface stylization,” in <i>SIGGRAPH 2023 Conference Proceedings</i>,
    Los Angeles, CA, United States, 2023.'
  ista: 'Tojo K, Shamir A, Bickel B, Umetani N. 2023. Stealth shaper: Reflectivity
    optimization as surface stylization. SIGGRAPH 2023 Conference Proceedings. SIGGRAPH:
    Computer Graphics and Interactive Techniques Conference, 20.'
  mla: 'Tojo, Kenji, et al. “Stealth Shaper: Reflectivity Optimization as Surface
    Stylization.” <i>SIGGRAPH 2023 Conference Proceedings</i>, 20, Association for
    Computing Machinery, 2023, doi:<a href="https://doi.org/10.1145/3588432.3591542">10.1145/3588432.3591542</a>.'
  short: K. Tojo, A. Shamir, B. Bickel, N. Umetani, in:, SIGGRAPH 2023 Conference
    Proceedings, Association for Computing Machinery, 2023.
conference:
  end_date: 2023-08-10
  location: Los Angeles, CA, United States
  name: 'SIGGRAPH: Computer Graphics and Interactive Techniques Conference'
  start_date: 2023-08-06
date_created: 2023-08-27T22:01:17Z
date_published: 2023-07-23T00:00:00Z
date_updated: 2023-09-05T07:22:03Z
day: '23'
department:
- _id: BeBi
doi: 10.1145/3588432.3591542
external_id:
  arxiv:
  - '2305.05944'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2305.05944
month: '07'
oa: 1
oa_version: Preprint
publication: SIGGRAPH 2023 Conference Proceedings
publication_identifier:
  isbn:
  - '9798400701597'
publication_status: published
publisher: Association for Computing Machinery
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Stealth shaper: Reflectivity optimization as surface stylization'
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2023'
...
---
_id: '12979'
abstract:
- lang: eng
  text: '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. '
acknowledgement: We thank Matthew S Zurawski for the 3D model of the car speed shape.
  This research has been supported by the Swiss National Science Foundation (SNSF,
  Grant 200502) and the FWF Lise Meitner (Grant M 3319).
article_number: '21'
article_processing_charge: No
author:
- first_name: Jorge
  full_name: Condor, Jorge
  last_name: Condor
- first_name: Michael
  full_name: Piovarci, Michael
  id: 62E473F4-5C99-11EA-A40E-AF823DDC885E
  last_name: Piovarci
  orcid: 0000-0002-5062-4474
- first_name: Bernd
  full_name: Bickel, Bernd
  id: 49876194-F248-11E8-B48F-1D18A9856A87
  last_name: Bickel
  orcid: 0000-0001-6511-9385
- first_name: Piotr
  full_name: Didyk, Piotr
  last_name: Didyk
citation:
  ama: 'Condor J, Piovarci M, Bickel B, Didyk P. Gloss-aware color correction for
    3D printing. In: <i>SIGGRAPH ’23 Conference Proceedings</i>. Association for Computing
    Machinery; 2023. doi:<a href="https://doi.org/10.1145/3588432.3591546">10.1145/3588432.3591546</a>'
  apa: 'Condor, J., Piovarci, M., Bickel, B., &#38; Didyk, P. (2023). Gloss-aware
    color correction for 3D printing. In <i>SIGGRAPH ’23 Conference Proceedings</i>.
    Los Angeles, CA, United States: Association for Computing Machinery. <a href="https://doi.org/10.1145/3588432.3591546">https://doi.org/10.1145/3588432.3591546</a>'
  chicago: Condor, Jorge, Michael Piovarci, Bernd Bickel, and Piotr Didyk. “Gloss-Aware
    Color Correction for 3D Printing.” In <i>SIGGRAPH ’23 Conference Proceedings</i>.
    Association for Computing Machinery, 2023. <a href="https://doi.org/10.1145/3588432.3591546">https://doi.org/10.1145/3588432.3591546</a>.
  ieee: J. Condor, M. Piovarci, B. Bickel, and P. Didyk, “Gloss-aware color correction
    for 3D printing,” in <i>SIGGRAPH ’23 Conference Proceedings</i>, Los Angeles,
    CA, United States, 2023.
  ista: 'Condor J, Piovarci M, Bickel B, Didyk P. 2023. Gloss-aware color correction
    for 3D printing. SIGGRAPH ’23 Conference Proceedings. SIGGRAPH: Computer Graphics
    and Interactive Techniques Conference, 21.'
  mla: Condor, Jorge, et al. “Gloss-Aware Color Correction for 3D Printing.” <i>SIGGRAPH
    ’23 Conference Proceedings</i>, 21, Association for Computing Machinery, 2023,
    doi:<a href="https://doi.org/10.1145/3588432.3591546">10.1145/3588432.3591546</a>.
  short: J. Condor, M. Piovarci, B. Bickel, P. Didyk, in:, SIGGRAPH ’23 Conference
    Proceedings, Association for Computing Machinery, 2023.
conference:
  end_date: 2023-08-10
  location: Los Angeles, CA, United States
  name: 'SIGGRAPH: Computer Graphics and Interactive Techniques Conference'
  start_date: 2023-08-06
date_created: 2023-05-16T09:34:13Z
date_published: 2023-07-23T00:00:00Z
date_updated: 2024-02-28T12:52:04Z
day: '23'
ddc:
- '004'
department:
- _id: BeBi
doi: 10.1145/3588432.3591546
external_id:
  isi:
  - '001117690500021'
file:
- access_level: open_access
  checksum: 84a437739af5d46507928939b20c0c28
  content_type: application/pdf
  creator: mpiovarc
  date_created: 2023-05-16T09:32:50Z
  date_updated: 2023-05-16T09:32:50Z
  file_id: '12983'
  file_name: Condor2023_supplemental.pdf
  file_size: 42323971
  relation: main_file
  success: 1
- access_level: open_access
  checksum: 0f5c8b242e8e7c153c04888c4d0c6f37
  content_type: application/pdf
  creator: dernst
  date_created: 2024-01-29T10:14:10Z
  date_updated: 2024-01-29T10:14:10Z
  file_id: '14893'
  file_name: 2023_Siggraph_Condor.pdf
  file_size: 26079404
  relation: main_file
  success: 1
file_date_updated: 2024-01-29T10:14:10Z
has_accepted_license: '1'
isi: 1
keyword:
- color
- gloss
- perception
- color compensation
- color management
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '07'
oa: 1
oa_version: Published Version
project:
- _id: eb901961-77a9-11ec-83b8-f5c883a62027
  grant_number: M03319
  name: Perception-Aware Appearance Fabrication
publication: SIGGRAPH ’23 Conference Proceedings
publication_identifier:
  isbn:
  - '9798400701597'
publication_status: published
publisher: Association for Computing Machinery
quality_controlled: '1'
status: public
title: Gloss-aware color correction for 3D printing
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2023'
...