When making a wall thickness 3D model look waterproof, focus on water-resistant material textures (like sealed paint or rubber coatings) and smooth, gap-free surfaces that mimic real impermeable walls.
Use glossy finishes or subtle water beading—these visual cues help users associate the model with waterproofing, since real waterproof walls lack cracks and reflect light uniformly.
For a quick tweak, apply a "wet" material preset in tools like Blender or add tiny water droplets to edges—this reinforces the waterproof look without extra complexity.