The Kiln Shell Laser is a contact-free measurement tool to determine deformations of kiln or dryer shells and other slowly rotating, large cylinders during operation. The system can be used to measure individual cross-sections as a spot-check as well as the whole kiln using several measurements. The steel shell of rotary kilns is exposed to high temperature. In case of excessive heat the shell might deform. In areas with deformations the refractory installation becomes typically difficult, which has a negative impact on its lifetime.