Proceedings: GI 2017

Ballistic Shadow Art

Xiaozhong Chen (McGill University), Sheldon Andrews (McGill University), Derek Nowrouzezahrai (McGill University), Paul G. Kry (McGill University)

Proceedings of Graphics Interface 2017: Edmonton, Alberta, 16-19 May 2017, 190 - 198

DOI 10.20380/GI2017.24

  • Bibtex

    author = {Chen, Xiaozhong and Andrews, Sheldon and Nowrouzezahrai, Derek and Kry , Paul},
    title = {Ballistic Shadow Art},
    booktitle = {Proceedings of Graphics Interface 2017},
    series = {GI 2017},
    year = {2017},
    issn = {0713-5424},
    isbn = {978-0-9947868-2-1},
    location = {Edmonton, Alberta},
    pages = {190 -- 198},
    numpages = {9},
    doi = {10.20380/GI2017.24},
    publisher = {Canadian Human-Computer Communications Society / Soci{\'e}t{\'e} canadienne du dialogue humain-machine},
    keywords = {Shadows, animation, optimization, physics simulation},


We present a framework for generating animated shadow art using occluders under ballistic motion. We apply a stochastic optimization to find the parameters of a multi-body physics simulation that produce a desired shadow at a specific instant in time. We perform simulations across many different initial conditions, applying a set of carefully crafted energy functions to evaluate the motion trajectory and multi-body shadows. We select the optimal parameters, resulting in a ballistics simulation that produces ephemeral shadow art. Users can design physically-plausible dynamic artwork that would be extremely challenging if even possible to achieve manually. We present and analyze number of compelling examples.