Use a low‑angle, diffuse light that comes from the left‑hand side of the model, about 30 degrees above the horizon. That keeps the moss detail sharp while the matcap gives a subtle sheen. Keep the texture tiles tight, no stretching, and bump map it at 2‑4% height to avoid glare. If you want that velvet‑chrome look, bump the surface a bit and use a high specular map with low roughness, but only in the upper right quadrant where the light hits. Stay quiet while you tweak, you’ll see the shadow lines pop before anyone else notices.