"Figma Is a Big Black Box:" The Mismatch Between the Interface and Its Underlying Structure

High-fidelity digital prototyping tools play a central role in commercial design workflows. One of the most common tools is Figma, which incorporates programming-like concepts such as constraints and parameterization in the form of auto layout, components, and smart animate features. We studied how designers engage with and appropriate these concepts as they used Figma to prototype an interactive system. We found recurring breakdowns that stem from a mismatch between the interface, which encourages imperative manipulation of objects on a canvas, and the underlying declarative structure, which is governed by constraints. Based on these findings, we characterize Figma as a complex interaction substrate and derive implications for the design of future constraint-reliant tools.