The aim of this work package is to develop equipment, models and associated strategies for dynamic performance evaluation/error compensation of medium to large machine tools (5 m³ – 50 m³) capable of reducing measurement times by 20 % without the need for stationary measurement locations and to allow in‑process machine behaviour to be investigated. This will be achieved by a combination of instrumental and methodical development. In Task 4.1, a fast, self-tracking interferometer will be developed and tailored for the dynamic measurements on large machine tools. The development will benefit from and build on previous developments in the EMPIR and EMRP projects: LUMINAR, Surveying, GeoMetre, and TIM. In Task 4.2 models and strategies will be developed further and take into account the new measurement capability developed in Task 4.1, while making use of developments and experience by the EMRP IND62 TIM project.