Vector Graphics Animation with Time-Varying Topology

Boris Dalstein, Rémi Ronfard, Michiel Van de Panne

ACM Transactions on Graphics (Proceedings of SIGGRAPH), 2015

A space-time continuous 2D animation depicting a rotating torus, created without 3D tools. First, the animator draws key cells (in blue) using 2D vector graphics tools. Then, he specifies how to interpolate them using inbetween cells (in green). Our contribution is a novel data structure, called Vector Animation Complex (VAC), which enables such interaction paradigm.


We introduce the Vector Animation Complex (VAC), a novel data structure for vector graphics animation, designed to support the modeling of time-continuous topological events. This allows features of a connected drawing to merge, split, appear, or disappear at desired times via keyframes that introduce the desired topological change. Because the resulting space-time complex directly captures the time-varying topological structure, features are readily edited in both space and time in a way that reflects the intent of the drawing. A formal description of the data structure is provided, along with topological and geometric invariants. We illustrate our modeling paradigm with experimental results on various examples.