To fix hidden edges in 3D models, adjust display settings (enable edge visibility) or modify geometry (recalculate normals, split overlapping edges).
Hidden edges often result from inverted normals (faces facing inward) or overlapping geometry—use tools like Blender/Maya’s "Recalculate Normals" or split edges to resolve these issues.
If edges still don’t show, switch to wireframe mode to isolate them, then use creasing or subtle beveling to enhance visibility without complex edits.