Developing 3D Annotation Features for 3D Digital Textbooks

Digital textbooks (DTs) have been established as the major media for future and smart education in South Korea. In general, DTs are implemented using two-dimensional (2D) web-based platforms with embedded 3D content, including images, motion graphics, animations, and video and audio. Recently, these 2D-based DTs have evolved into a 3D-based interface by adopting various types of 3D virtual environments. Accordingly, a number of 3D DTs have been developed; however, these are mainly focused on the implementation of the basic features of DTs, including displaying text and images, viewing pages, zooming in and out, indexing, moving to a certain page, and finding a specific text or object. Furthermore, these have not yet been comprehensively implemented, and further development is required to provide more diverse input and annotation features to facilitate better dynamic interaction between students and DTs. Here, we introduce 3D annotation features that were designed and implemented to enable users to freely annotate on 3D DTs with various forms of input, facilitating dynamic user interactions. These include stylus writing, underlining, highlighting, drawing lines and shapes, and the insertion of textboxes, sound and video files, and voice memos. Students may highlight text or place notes to give commentary on the content of DTs using stylus writings, lines, shapes, text, multimedia files, and voice memos to aid their studying. The 3D annotation features were developed using the eXtensible 3D (X3D) standard, which is an XML-based international standard file format for representing scenes and 3D objects in computer graphics, extended from the virtual reality modeling language (VRML), along with the Java Applet and JavaScript. We aim to enhance student engagement in the learning process by supporting various forms of dynamic interaction features via a natural user interface. We believe that the approaches we describe provide a viable solution to enable 3D annotation on DTs.