PHASE 1: VISUAL DECONSTRUCTION - **Fabric Physics:** The source garment appears to be a lightweight, matte woven fabric (likely cotton poplin or a viscose blend). It has a low stiffness index, meaning it should drape softly rather than stand rigid. Specularity is low (diffuse reflection), so there should be no plastic-like shine, only soft highlights on the shoulder ridges. - **Key Features:** The high-contrast "Bandana/Paisley" patchwork pattern is the primary visual anchor and must retain its distinct geometric alignment. The "Camp Collar" (open, flat-laying collar) structure must replace the user's current stiff dress-shirt collar. The chest pocket on the viewer's right must preserve its pattern continuity. PHASE 2: FIT & DRAPE SIMULATION - **Body Mapping:** The source is short-sleeved, while the user is wearing long sleeves. The simulation must replace the user's blue sleeves with the target's short sleeves and generatively in-paint bare skin on the forearms to match the user's facial skin tone. The garment must accommodate the user's midsection curvature (convex drape) rather than hanging vertically flat like on the source model. The hemline should naturally fall *over* the belt line (untucked logic) given the casual nature of the source shirt, overriding the user's current tucked-in state. - **Occlusion Handling:** The user's hands are free of the torso, simplifying occlusion. However, the simulation must strictly layer the shirt *behind* the user's wrist if the hand grazes the hip. The shirt collar must sit *under* the user's jawline and neck skin, completely masking the existing blue collar. PHASE 3: ENVIRONMENT & LIGHTING - **Light Match:** The user is illuminated by a strong, natural light source from the viewer's left (window light), creating a gradient from light-left to shadowed-right. The new black shirt must render with high exposure on the left shoulder/flank and deep shadows on the right. The white paisley print must absorb the ambient yellowish hue of the room's walls to avoid looking sterile white. - **Color Calibration:** The "Black" of the shirt must be lifted from absolute #000000 to match the black point of the user's environment (referencing the darkest shadows in the background door) to ensure the texture of the fabric remains visible. PHASE 4: IDENTITY PROTECTION - **Facial Lock:** Absolute freeze required on the user's face, neck structure, and hair. The transition line between the new open collar and the user's neck must be seamless. - **Body Integrity:** Strictly prohibit volumetric reduction. The garment mesh must expand to fit the user's shoulder width and abdominal depth. Do not warp the user's torso to match the slimmer physique of the source model; the shirt modifies the user, the user does not modify for the shirt.