This chapter describes the modelling and layout of process equipment and civil items. These include items such as pumps, vessels, walls and heat exchangers, which are modelled within the major hierarchical elements Equipment, Structure, Ptrack and Substructure. These elements own primitive geometric shapes and holes which are dimensioned and assembled to form a suitable model. The items can then be positioned and orientated as a whole by using one of the comprehensive positioning commands - MODEL items can either be positioned at a known co-ordinate, or moved by a given distance or clearance. The same commands can be used to modify existing positions, orientations and dimensions. There are also a number of special Plant modification facilities that are described in a later part of the manual.