Visualization of complex multi-dimensional data is a key in many application domains. We developed a "proof of concept" demonstrator for a medical scenario, which shows how gestures can be used to interact with medical 3D data. The demonstrator is also suitable for gesture interactions with 3D data from other fields of application, such as production or mobility. An interaction concept for contactless interaction with 3D data and the corresponding gestures was designed for the demonstrator. Thereafter, algorithms for the recognition of hand gestures and hand poses were developed. A leap motion sensor was used to record the inputs. A Unity application is used for the visualization of the 3D data, the operating elements and the user feedback.