The three are very different and distinct processes. Engraving is a process by which a design is produced by cutting grooves into a hard, flat surface with hard steel tools. The surface is usually some type of metal, and the object can be a decoration in itself, or it can be used to print images, called engravings, on paper.
Etching uses strong acid to cut into the unprotected parts of a metal surface to create a design. The result can be used to make prints similar to engravings. It was an important method for creating the old master prints. It was also used to decorate armor, old guns, plates and cups.
Sculpture is produced by shaping a material such as stone, metal or wood to produce three-dimensional artwork. Clay and plaster can also be molded into sculptuures. Steel tools such as knives, gouges, and chisels are used by the sculptors to cut and chip away the excess parts of the materials.
Etching uses strong acid to cut into the unprotected parts of a metal surface to create a design. The result can be used to make prints similar to engravings. It was an important method for creating the old master prints. It was also used to decorate armor, old guns, plates and cups.
Sculpture is produced by shaping a material such as stone, metal or wood to produce three-dimensional artwork. Clay and plaster can also be molded into sculptuures. Steel tools such as knives, gouges, and chisels are used by the sculptors to cut and chip away the excess parts of the materials.