The invention deals with methods for assembly and disassembly, especially suitable for assembly and disassembly by a computer. In relation to assembly, a component (10) is positioned in assembly (70) in accordance with a proposed position. The composent (10) is confirmed as being in its correct spatial position in the assembly (70) by sensing means (38) or (46) capable of sensing spatial relationship and/or connection of the component (10) in relation to the assembly (70). Information regarding the sensed spatial relationship and/or connection is communicated to information processing means. A method for disassembly is also disclosed. The assembly and disassembly methods may require steps to be taken in a chosen sequence. The component (10) itself is also described, as is an improved assembly system which includes the component (10) together with information processing means.