This paper deals with the component method for the structural design of steel joints in the 3D modelling of loads. The essential features of the method are presented in terms of the local and global analysis model. There is a discussion about the location of the local joint model, the definition of generalized joint displacements and the generic nature of the method. The proposed method is verified for a beam-to-column joint. Verification is carried out by a detailed 3D non-linear finite element analysis of a single joint. Other results in the literature are discussed briefly. One of the new components used in 3D modelling is introduced here. The proposed 3D component method seems to work rather well for moment resistances of joints in both ambient and fire conditions. Initial rotational stiffness needs to be studied more. Validation of the 3D component method is continuing with experiments on the end plate splice joints of rectangular tubular structures.