  Repetitive patterns are ubiquitous in natural and human-made objects, and can
be created with a variety of tools and methods. Manual authoring provides
unmatched degree of freedom and control, but can require significant artistic
expertise and manual labor. Computational methods can automate parts of the
manual creation process, but are mainly tailored for discrete pixels or
elements instead of more general continuous structures. We propose an
example-based method to synthesize continuous curve patterns from exemplars.
Our main idea is to extend prior sample-based discrete element synthesis
methods to consider not only sample positions (geometry) but also their
connections (topology). Since continuous structures can exhibit higher
complexity than discrete elements, we also propose robust, hierarchical
synthesis to enhance output quality. Our algorithm can generate a variety of
continuous curve patterns fully automatically. For further quality improvement
and customization, we also present an autocomplete user interface to facilitate
interactive creation and iterative editing. We evaluate our methods and
interface via different patterns, ablation studies, and comparisons with
alternative methods.
