Workflow Analysis and Interface Design for 3D Gaussian Splatting Using a Hierarchical Task Analysis Approach

This study investigates the impact of user workflows and iterative decision-making on task efficiency in 3D Gaussian splatting (3DGS)-based 3D reconstruction. In current 3DGS workflows, the absence of clearly defined stages and structured processes leads users to repeatedly interpret intermediate results and revisit earlier phases, thereby increasing cognitive load and reducing efficiency. To address this issue, data were collected from ten expert users experienced in 3DGS-based workflows through semi-structured interviews and shadowing observations. To systematically decompose complex and iterative user workflows, hierarchical task analysis (HTA) was employed. The results show that the workflow can be organized into six stages: (1) Data Acquisition, (2) Project Setup, (3) 3DGS Training, (4) Result Inspection, (5) Quality Refinement, and (6) Output Utilization. User workload was primarily concentrated in the Result Inspection and Quality Refinement stages, characterized by repeated retraining and decision-making processes. Based on this analysis, four issues were identified: ambiguity in early-stage configuration, limited visibility of progress status, difficulty in identifying the causes of failure, and inefficiencies in editing operations. To address these issues, an interface design consisting of four functional areas is proposed: (1) Mode & Capture Setup, (2) Progress Management, (3) Error Review, and (4) Editing Efficiency. Evaluation by expert users indicates that the proposed interface was rated significantly higher than the existing 3DGS interface across all functional areas (p < 0.01). Higher scores were observed in Error Review (M = 4.05 vs. 1.53) and Editing Efficiency (M = 4.55 vs. 1.88) compared to the existing interface. These findings suggest that interface support for error review and editing tasks plays an important role in improving workflow usability. This study structures 3DGS workflows from a user-centered perspective and identifies the key stages where iterative decision-making is most concentrated. Based on these findings, it proposes directions for 3DGS interface design and empirically demonstrates the effectiveness of the proposed design.