To make a 3D model’s normals look correct, align vertex normals with its geometry, fix flipped faces, and use normal maps properly (if needed).
Smooth normals for rounded shapes (e.g., spheres) create soft, gradual shading, while hard edges (split normals) define sharp corners (e.g., cubes) for crisp shadows. For normal maps, bake from a high-poly model to low-poly using matching UVs—this preserves fine details without distortion.
In tools like Blender or Maya, use the "Face Orientation" overlay (blue = front, red = back) to fix flipped normals (a common issue where faces face inward).
If shading looks off, recalculate normals in your software (e.g., Blender’s "Recalculate Normals" function) or tweak the normal map’s strength (start with 0.5–1.0) until lighting matches the model naturally.