## 1 Introduction  
The product design industry is a high-value sector defined by style, quality, and customization. The evolving market landscape and advancements in industrial processes [1] demand solutions that actively involve customers in the configuration of complex products with emotional value.  
VR configurators address these needs by providing a virtual platform to enhance product awareness by means of a flexible purchasing experience. These tools enable users to visualize, manipulate, and interact with complex designs firsthand [2], while also experiencing product functionalities interactively.  
The spatial perception enabled by VR [3] has the potential to revolutionize how customers evaluate products, supporting industries that aim to convey comfort and ergonomic qualities, including automotive, interior design, camping equipment, and nautical applications.  
VR also supports collaboration through shared and remote presence, enabling professionals, sales assistants, or other users (e.g., relatives or partners) to participate in the configuration process (Figure 1). This creates a more dynamic customization experience while providing foreign customers with remote tools to preview products realistically, eliminating the cost and inconvenience of international travel.  
Additionally, the growing focus on eco-sustainability supports the adoption of low-impact remote solutions [4], enhancing the competitiveness of large, heavy products such as campers, boats, and houses produced by SMEs with limited logistics infrastructure and far from major trade fairs.  
Despite VR's potential, research on collaborative customization for emotionally impactful [5] products (e.g., yachts) remains limited; while a few VR solutions offer multi-user configuration tools with photorealistic visuals, these are often expensive and poorly optimized for mid-tier devices, underscoring the need for adaptive and flexible solutions to enable realistic previews through high-quality rendering.  
To address these gaps, we introduce MAGIC (Multi-user Advanced Graphic Immersive Configurator), a collaborative cross-platform (VR/desktop) solution specifically designed for configuring complex, high-value products. MAGIC combines multi-user functionalities with optimized photorealistic graphics to deliver a scalable and immersive customization experience, even on lower-performance hardware.  
MAGIC also advances research by providing a user study conducted in a real-world industrial context at a local shipyard, addressing the limitations of traditional 2D visualization systems that often fail to engage customers effectively. Through its immersive and intuitive interface, the system bridges the gap between technical CAD designs and customer expectations, offering a practical, accessible, and efficient solution for industries where emotional engagement and collaborative design are essential.  
Overall, this research contributes to the scientific literature and promotes eco-sustainability by achieving the following:  
* Developing MAGIC, a novel VR collaborative configuration system with real-time optimized photorealistic rendering;
* Providing a case study of MAGIC in a shipyard as a real-use scenario and gathering impressions from end users.  
Figure 1: Multi-user VR configuration of a highly customizable yacht using MAGIC in a three-person shared session: the yellow and red users evaluate the optimal distance between the helms (**left**), while the blue user observes the deck from the hatchway (**right**).