The early tridimensional works are accomplished starting from 1948. Depending on the different materials, 3D’s could be distinguished in two types : “transparent” , if the support is glass or sheets of plastic, and “opaque” if the work is made of wood, metal sheets, or plexiglas. The “opaque” 3D belong to the mature production and they have been created for the most part since 1956.
Both in transparent and opaque 3D’s, the image is the result of a combination of drawings or cut out shapes layed on different planes and then assembled “in order to produce the effect of depth when superimposed” (G. Belli – A. Marchionne 1987).
In some of the 3D's the different surfaces are stratified into a wooden frame; on the contrary in some opaque 3D's on wood, the frame is considered joined with the work. For their particular thickness some of 3D could be considered in a boundary area of definition between painting and sculpture.