How Fitts' Fits in 3D: A Tangible Twist on Spatial Tasks

TL;DR

This paper extends Fitts' Law into 3D mixed reality, analyzing how object size and distance affect pointer task difficulty in PointARs, revealing new insights and design guidelines for 3D interaction.

Contribution

It introduces an analysis of Fitts' Law in 3D mixed reality, highlighting the impact of object size and distance on task complexity and proposing practical interaction guidelines.

Findings

Increased distance raises task difficulty as predicted by Fitts' Law.

Larger objects unexpectedly increased complexity, possibly due to tracking limitations.

Optimal interaction occurs with 1.5-2 inch objects within 2-inch distances.

Abstract

Expanding Fitts' Law into a 3D context, we analyze PointARs, a mixed reality system that teaches pointer skills through an object manipulation task. Nine distinct configurations, varying in object sizes and distances, were explored to evaluate task complexity using metrics such as completion time, error rate, and throughput. Our results support Fitts' Law, showing that increased distances generally increase task difficulty. However, contrary to its predictions, larger objects also led to higher complexity, possibly due to the system's limitations in tracking them. Based on these findings, we suggest using tangible cubes between 1.5" and 2" in size and limiting the distance between objects to 2" for optimal interaction in the system's 3D space. Future research should explore additional configurations and shapes to further validate Fitts' Law in the context of 3D object manipulation in systems like PointARs. This could help refine guidelines for designing mixed reality interfaces.