PHASE 1: VISUAL DECONSTRUCTION - **Fabric Physics:** The source garment is a textured, ribbed knit (likely cotton or cotton-blend tank top). It possesses a matte finish with high light absorption, meaning no specular highlights. The physics engine must treat this as a soft, semi-elastic material that conforms to the body but maintains a structural weight, distinct from the stiffness of the user's current button-down shirt. - **Key Features:** The specific waffle/ribbed texture of the black fabric is critical for realism and must be upscaled. The deep scoop neckline and the specific binding thickness around the neck and armholes must be preserved. The hemline appears standard and straight. PHASE 2: FIT & DRAPE SIMULATION - **Body Mapping:** This is a complex geometry transformation from a long-sleeve shirt to a sleeveless tank top. The simulation must generate accurate skin texture for the user's arms where the current sleeves exist. The tank top must interact with the "crossed arms" pose; the fabric should pull tight across the scapula and upper back, while bunching and folding significantly directly above the forearms due to the compression of the crossed posture. The neckline will sit lower than the current collared shirt, exposing the upper chest/clavicle area. - **Occlusion Handling:** **CRITICAL:** The user has arms crossed over the torso. The forearms, wrists, and hands act as foreground occlusions. The new tank top must be rendered *behind* these limbs. The shadow of the crossed arms must be cast realistically onto the stomach area of the new tank top. PHASE 3: ENVIRONMENT & LIGHTING - **Light Match:** The user is in a high-contrast outdoor environment with harsh sunlight coming from the upper-right (user's left). The tank top must exhibit bright daylight exposure on the user's right shoulder and chest, transitioning to deep, sharp shadows on the user's left side and beneath the crossed arms. The texture of the ribbing should be emphasized by this side-lighting. - **Color Calibration:** The source garment is deep black. In this bright, warm, yellow-dominant environment (sunlight + reflection from the fort), the black level must be lifted slightly to a dark charcoal to prevent "black crush" (loss of detail). A subtle warm yellow fill light should be applied to the shadows of the shirt to simulate bounce light from the surrounding architecture. PHASE 4: IDENTITY PROTECTION - **Facial Lock:** The user's entire head, including the hairline, jawline, and ear visible on the profile, must be masked and frozen. The sunglasses/eye area (if visible, though eyes look squinted/shadowed) and facial stubble must remain untouched. - **Body Integrity:** The user's shoulder width and torso volume must be preserved. Do not slim the waist or broaden the shoulders artificially. The skin tone generated for the exposed arms (replacing the sleeves) must perfectly match the user's face and neck skin tone.