This project will develop methods for instant real-time 3D as-built CAD modelling of nuclear plant, including segmentation of the scene into a collection of salient objects, 3D modelling and real-time 3D motion tracking of these objects, to facilitate planning and execution of remote handling and decommissioning operations, spanning multiple UK sites. We will use novel computational vision techniques to recognise (from CAD models) objects in point clouds extracted from optical laser scanners, build new CAD models for unknown objects, and track the 3D poses of objects that move. It currently takes between hours and days to assemble a single CAD model of an environment and the environment is modelled as a single monolithic object, so real-time 3D motion tracking of these objects will represent a breakthrough in capability.