Complete the text:Casting is a 6 ,000 year old process. It is the oldest and most well-known technique based on three fundamental steps: moulding, melting and пустоcasting . Fi rst the pattern is made to form the mould. Then an empty mould is created, and finally the empty cavity is filled with molten metal which is then left to solidify into the shape. Casting materials are usually пустоmetals but can also be plastic, resin or various cold materials for example пустоconcrete . Casting is usually used for making complex shapes.