Scientific and technological advances during the last decade in the fields of image acquisition, data processing, telecommunications, and computer graphics have contributed to the emergence of new multimedia, especially 3D digital data. Modern 3D imaging technologies allow for the acquisition of 3D and 4D (3D video) data at higher speeds, resolutions, and accuracies. With the ability to capture increasingly complex 3D/4D information, advancements have also been made in the areas of 3D data processing (e.g., filtering, reconstruction, compression). As such, 3D/4D technologies are now being used in a large variety of applications, such as medicine, forensic science, cultural heritage, manufacturing, autonomous vehicles, security, and bioinformatics. Further, with mixed reality (AR, VR, XR), 3D/4D technologies may also change the ways we work, play, and communicate with each other every day.