In recent motion graphics practice, various techniques called Fake 3D are being used and developed as part of motion graphics’ own expressive vocabulary for expressing depth and three-dimensionality in flat 2D environments without 3D-specialized too...
In recent motion graphics practice, various techniques called Fake 3D are being used and developed as part of motion graphics’ own expressive vocabulary for expressing depth and three-dimensionality in flat 2D environments without 3D-specialized tools or rendering. However, such spatial depth expression has mainly been handled based on the intuition and experience of practitioners. Due to the lack of basic research on motion graphics and the tendency to rely on theories from related fields such as film and animation, research that academically analyzes and systematizes these expressions remains insufficient.
To examine spatial depth cues in 2D motion graphics, this study set Fake 3D as the scope of inquiry and selected 24 2D motion graphics projects through a three-stage screening process from works selected for Motion Curation on Behance, Adobe’s design portfolio platform. To prevent sample bias, four scenes were extracted from each project, resulting in a total of 96 scene-level samples. This study reviewed the theoretical discussions from related fields such as film and animation, and derived an analytical framework for spatial depth cues based on monocular depth cues and the graphic and motion components of motion graphics. In addition, part of the sample set was independently analyzed by two raters to assess the consistency of applying the analytical framework and the reliability of the researcher’s analysis. An expert review was also carried out with seven practicing motion graphics designers with more than three years of professional experience to enhance the validity of the researcher’s analytical results.
As a result of the analysis, the visual cues that make up spatial depth in 2D motion graphics were derived according to six criteria: relative size, occlusion, linear perspective, aerial perspective, light and shadow, and shape constancy. In particular, the depth perception cues caused by motion, which had been grouped under a single concept of motion parallax in existing depth perception theory, were subdivided into five graphic cues and six motion cues, making a total of 11 visual spatial depth cues. Looking at the characteristics of each cue, occlusion appeared with the highest frequency in both graphic and motion cues, and was confirmed as the most basic and efficient cue for forming spatial depth. Linear perspective has a limitation in that viewpoint movement cannot be freely expressed in a 2D environment, but cues such as relative size and occlusion were shown to compensate for this limitation. Shape constancy, as a motion-based spatial depth cue, contributed to the perception of an object’s three-dimensional structure by showing changes in its form.
The 11 spatial depth cues derived in this study shared certain characteristics in how they deliver depth information, and were classified into three types: relational, spatial, and form-based. The relational type shows depth order through comparison between objects without showing the degree of depth, and includes relative size, occlusion, light and shadow, and aerial perspective in graphic cues. The spatial type shows the degree of depth through rules that are applied consistently across the entire space, and includes linear perspective, aerial perspective, light and shadow, shape constancy, and relative size in motion cues. The form-based type forms spatial depth by allowing viewers to perceive the three-dimensional structure of a single object, and includes linear perspective, light and shadow, shape constancy, and occlusion in motion cues. Among the 96 samples analyzed, the three types appeared together in 90 samples. This confirmed that spatial depth expression in 2D motion graphics does not rely on a single attribute, but that the hierarchy between objects, the rules of space, and the three-dimensional structure of the object are utilized together, each serving its own role in forming spatial depth.
This study clarifies how each cue contributes to the formation of spatial depth through the analysis of spatial depth cues, and confirms that motion is also a key design element in forming spatial depth in 2D motion graphics. The spatial depth cues and type classification derived from this study serve as a basic analytical foundation for expressing spatial depth in motion graphics, and can be utilized as a standard for planning and communicating spatial depth expression in practice, as well as basic educational material in motion graphics education for understanding and explaining graphic and motion components.