Open Problems in 3D Model and Data Management Topics: CAGD/CAD/CAM Systems; Fundamental Methods and Algorithms; Graphical Interfaces; Integration and Interoperation Between 3D Documents and Web/Multimedia Technologies, Including the Semantic Web; Modeling and Algorithms; Processing Frameworks and Data Structures; Scene and Object Modeling; Virtual Reality Tools and Languages In Proceedings of the 15th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications - Volume 0VISIGRAPP, 347-354, 2020 , Valletta, Malta