PHASE 1: VISUAL DECONSTRUCTION - **Fabric Physics:** The source garment is a standard jersey knit (likely 100% cotton or a cotton-poly blend). It possesses a matte finish with low reflectivity. The physics engine must simulate a medium-weight drape—pliable enough to show soft folds but structural enough to hold the sleeve shape. It should not shine like silk or crease sharply like starched linen. - **Key Features:** The distinct ribbed crew neckline must be preserved and aligned with the user's collarbone. The double-needle stitching on the sleeve hems and bottom hem must remain visible. The solid navy blue color uniformity is critical, maintaining the slight heathered texture if present in the high-res source. PHASE 2: FIT & DRAPE SIMULATION - **Body Mapping:** The user has an athletic build with a slight torso twist to his left. - **Shoulders/Chest:** The fabric must stretch slightly across the right pectoral and right shoulder blade, as the user's right arm is positioned behind his back. - **Waist:** The garment should not be tucked in; it must hang naturally over the waistband of the jeans, creating slight compression wrinkles where it hits the hips. - **Sleeves:** The left sleeve should hang vertically due to gravity. The right sleeve will be pulled back and slightly upward due to the arm position. - **Occlusion Handling:** The user's neck and jawline are the primary boundaries; the new collar must sit beneath the chin shadow. The user's hands are clear of the torso, but the right arm disappears behind the back; the shirt body must render *in front* of the right arm's insertion point into the torso but preserve the disappearance of the forearm. PHASE 3: ENVIRONMENT & LIGHTING - **Light Match:** The target environment features outdoor, diffuse daylight, likely shaded, coming from overhead/front-left. The source garment is studio-lit. The new render must cast soft, diffuse shadows under the pectorals and in the fabric folds. The deep navy color must interact with the ambient light, absorbing some slight green bounce-light from the hedge background to ground it in the scene. - **Color Calibration:** The studio lighting of the source garment is warm. The target scene is cooler (outdoor daylight). The navy blue must be color-graded to match the exposure of the user's current grey shirt—specifically, the black point levels must match the user's black hair and jeans' shadows to prevent the shirt from looking "pasted on." PHASE 4: IDENTITY PROTECTION - **Facial Lock:** Absolute pixel-lock on the user's face (from chin up), ears, and hairstyle. The skin tone on the neck and arms must remain unaltered. - **Body Integrity:** The simulation is strictly forbidden from altering the user's shoulder width or torso volume. The underlying mesh must match the user's current biomechanics; do not slim the waist or broaden the chest beyond the natural drape of the fabric. The jeans, sneakers, and watch must remain untouched.