PHASE 1: VISUAL DECONSTRUCTION - **Fabric Physics:** The source garment is a standard cotton or cotton-poly blend jersey. It possesses a matte finish with low specular highlights. The physics engine must simulate medium-weight flexibility—capable of micro-wrinkles at tension points but heavy enough to drape vertically without fluttering. - **Key Features:** The circular "The Vector Lab" logo on the left chest is critical and must be positioned accurately over the user's left pectoral muscle. The ribbed crew-neck collar structure and the double-stitched hemline must be preserved. The orange hue (terracotta) is the primary aesthetic identifier. PHASE 2: FIT & DRAPE SIMULATION - **Body Mapping:** The user is standing with hands clasped behind the back. This pose expands the chest and pulls the shoulders back. Consequently, the fabric must stretch slightly horizontally across the pectorals and clavicle area. The source garment has standard sleeves, whereas the user's current sleeves are rolled; the simulation must generate standard, unrolled sleeves that hang naturally around the biceps, replacing the existing silhouette. The hem should fall naturally over the waistband of the jeans, utilizing a relaxed fit rather than the current tucked-in look. - **Occlusion Handling:** This constitutes a "low occlusion" scenario. There is no long hair, jewelry, or hand obstruction over the torso. The primary boundary calculation is strictly at the neck line and the waist/hip intersection where the shirt overlaps the denim jeans. PHASE 3: ENVIRONMENT & LIGHTING - **Light Match:** The user image utilizes soft, diffuse studio lighting, with the key light source positioned upper-left (indicated by highlights on the user's forehead and right shoulder). The generated orange shirt must exhibit brighter diffuse reflection on the left shoulder and chest, transitioning to soft shadows on the user's right side and under the armpits. - **Color Calibration:** The user image has a cool, high-key studio white balance. The source cloth image is warm. The orange texture needs to be color-graded to match the user's neutral environment to prevent the "sticker effect," ensuring the shadows on the orange fabric match the contrast levels of the user's jeans. PHASE 4: IDENTITY PROTECTION - **Facial Lock:** The user's head, including the neck up to the suprasternal notch, jawline, and hair, must be absolutely frozen. The skin tone on the arms and neck must remain unaltered. - **Body Integrity:** The user has an athletic/muscular build. The simulation must drape the cloth over his existing volume (broad shoulders, visible chest definition) without warping his underlying anatomy. Do not slim the waist or reduce shoulder width.