L.ink: Procedural Ink Growth for Controllable Surprise

Control, a common principle in interface design, helps artists achieve desired outcomes when using creativity support tools. However, surprise also plays a role in creative practice by facilitating introspection and adaptation. Consequently, creativity support tools face the challenge of balancing these two properties. We present L.ink, a digital illustration tool that empowers artists to draw with controllable yet unpredictable procedural growth styles powered by L-systems. Through a formative study of an early prototype of the system, we identify three types of surprise and adapt our design with a direct-manipulation editing interface with live visual feedback and a hand-drawn stamp tool to afford control and mitigate unwanted surprise. We further evaluate how controllable surprise impacts creative workflow and experience through a task-based study with 12 artists. Based on our observations, we extract guidelines for when and how to effectively incorporate unpredictability into creativity support tools.