Frank Gehry, in selecting the cladding for the Guggenheim Museum in Bilbao, was inspired by the feathers and scales found on various animals. He observed their arrangement and their ability to allow movement, a theme that fascinates him in relation to natural systems covering curved surfaces, similar to those in the museum. Gehry chose to use rigid "scales" arranged in overlapping layers. The key distinction between the museum's cladding and the animals' skin is that the animals' skin is adapted for movement, while the building's skin is not, resulting in different covering systems.

From the beginning, Gehry wanted these components to be metallic and evaluated several options involving a variety of materials. He ruled out the use of stainless steel because of his perception that it would not integrate with the Bilbao sky. He also rejected the idea of using copper or other metals. In the end, he opted to use titanium parts, a relatively expensive material compared to the more affordable materials used in his earlier works. The final alloy is composed primarily of titanium, with a significantly higher proportion of titanium in the mix. The parts are extremely thin sheets, about one-third of a millimeter thick, which allows them to adapt perfectly to the curves of the building.

Each of these pieces has a unique and specific shape depending on its location, and these precise shapes were determined through the use of CATIA. In addition, each piece has a slight padding to ensure a perfect fit in place, a process known as "boatiné." In some areas of the facades, patches can be found formed by sets of sheets with slightly different colors due to variations in the metal alloy present in each piece. Stippling is also observed on certain facades, particularly those facing north. This sputtering is caused by a chemical reaction between the sheets, the ambient humidity and the hooks that hold the parts, which are not made of titanium. This reaction gives rise to galvanic couples and manifests itself as sputtering that affects the aesthetics of the building.