PHASE 1: VISUAL DECONSTRUCTION - **Fabric Physics:** The source garment is a cotton jersey or cotton-blend knit. It features a matte finish with low specularity (no shine). The physics simulation must account for "stretch" rather than "flow," meaning it will contour to the body's curvature rather than hanging loosely like the current red tunic. - **Key Features:** The three white buttons on the Henley-style placket are the primary focal point and must remain centered. The crew neckline and the specific short-sleeve length must be preserved. The hemline is straight but soft. PHASE 2: FIT & DRAPE SIMULATION - **Body Mapping:** The User is leaning back and to her left against a sofa. The new green shirt must reflect this gravity shift; the fabric should pull slightly taut across the right ribcage and bunch slightly on the left side where the torso compresses against the cushion. Since the source garment has short sleeves and the target garment has 3/4 sleeves, the simulation must accurately render skin texture on the user's forearms where the red sleeves currently exist. - **Occlusion Handling:** The user's long, dark hair cascades over both shoulders and rests on the upper chest. This is a critical occlusion layer; the hair must be masked out and composited *on top* of the new green fabric. The watch on the left wrist and bangles on the right wrist are likely below the new sleeve line, but if overlap occurs, jewelry takes precedence. PHASE 3: ENVIRONMENT & LIGHTING - **Light Match:** The target environment ("Glass House") has complex, multi-source lighting. There is strong, warm overhead lighting (tungsten hanging lamps) creating top-down highlights. The green shirt must receive these warm highlights on the shoulder seams and upper chest. - **Color Calibration:** The source green is currently lit by flat, cool white indoor light. It must be color-graded to accept the warm amber cast of the target room. Shadows on the garment (specifically under the bust and near the sofa contact point) must match the dark contrast levels of the user's jeans. PHASE 4: IDENTITY PROTECTION - **Facial Lock:** Absolute freeze on the facial region from the chin upwards, including the neck geometry. The user's hairstyle and hairline must remain untouched. - **Body Integrity:** The user's leaning posture and natural body volume must be preserved. The tight fit of the green shirt should not result in digital slimming or warping of the user's waist or bust size; the garment must deform to the body, not the body to the garment.