Head Model Studio - Art Study positions itself as a specialized reference tool for digital artists seeking to improve their portrait drawing capabilities. Developed by Wes Castain, the application leverages classical art techniques and anatomical study principles to create a structured learning environment for portrait artists working on iOS and iPadOS devices. The application's core functionality revolves around 25 meticulously crafted 3D head models, ranging from simplified planar structures to highly detailed anatomical studies. These models include five classical reference sculptures that provide historical context alongside modern anatomical representations. Each model features full 360-degree rotation capability, adjustable lighting conditions, and zoom functionality that allows artists to examine facial features from multiple angles and lighting scenarios. The progression system from basic to complex models enables users to build their understanding systematically rather than overwhelming beginners with advanced anatomy. User experience demonstrates thoughtful design choices tailored to artists' practical needs. The interface maintains minimalistic controls that prioritize the reference models while providing essential tools for study. The pinch-to-zoom functionality responds with precision, allowing detailed examination of facial features, while the rotation controls provide smooth orbital movement around each model. Real-world usage patterns suggest artists typically employ the application during sketching sessions, using the adjustable lighting to understand how shadows fall across facial planes and the rotation feature to study head proportions from multiple viewpoints. Without available user reviews for specific analysis, the application's 4.65/5 rating suggests generally positive reception among its user base. The high rating indicates satisfaction with the core reference functionality, though the absence of detailed reviews prevents examination of specific praise or criticism regarding particular features or implementation details. The application demonstrates notable strengths in its structured learning approach and quality of 3D models, though limitations include the relatively small library of models compared to some desktop alternatives and the absence of additional learning materials beyond the reference models themselves. Ideal use cases include portrait artists seeking mobile reference tools, students learning facial anatomy, and digital illustrators looking for reliable study references during commutes or outside studio environments.