Barkchip: Grab a real tree and feel its grain, the way it shifts under your palm. Those tiny ridges and knots aren’t random – they’re the plant’s way of handling stress, water and light. Scan a bark cross‑section with a micro‑CT or a high‑res camera, then map those contours onto your 3D model. For metal or polymer, use a CNC or laser with a variable feed that mimics the uneven ridges; add a little stochastically random offset so it never looks perfectly smooth. If you’re into living material, embed a thin layer of biodegradable polymer that swells with humidity; it will make the texture evolve and look more alive. Don’t aim for a flawless copy – let the imperfections be your guide. That’s how you turn a living surface into a living design.