## 7 Evaluation
### First Study  
The first part of the questionnaire introduced the study and objectives and asked for demographic information (age, gender, and profession). The second part elicited expectations regarding content and interactions: it displayed video-vignettes for the virtual representations of the various pages of a Tangible VR Book prototype and asked users several seed questions regarding what they would expect to see in the cover/back-cover of the book, as well as how they expected to interact with audio/video, 3D models, and hyperlinks inside the book. The videos in these vignettes did not show any interaction nor did they depict the user handling the book (Figure 7(a)). This was so as to reduce the influence on the participants since the goal was to elicit expectations. The third part asked for feedback regarding the usability of the Tangible VR Book: it showed video-vignettes with side-by-side compositions depicting a third-person view of a user manipulating the physical Tangible VR Book and the respective first-person virtual view. Each video showed interaction with a different part of the book (interaction with video/audio, interacting with the portals, and 3D model inspection; Figure 7(b)). We also asked users for their general opinion regarding the prototype (disliked/not interesting, liked/interesting, liked it very much/very interesting), and additional open feedback. The prototypes used in these vignettes were simplified versions of the prototype described in the previous section. With the intention of not drawing too much attention to these particular interactions, the prototype used for these vignettes did not show the gesture or tangible slider. Figure 8: Example vignettes for the second and third parts of the questionnaire. Results and Discussion  
The online questionnaire was available during 18 days. Twenty one participants responded to the online questionnaire, providing over 200 comments in total. The self-described professional activities of the respondents were \"student\" (5), \"designer\" (4), \"professor\" (2), \"VR developer\" (2), \"marketing\" (2), \"electrical engineer\" (1), \"public servant\" (1), \"researcher\" (1), \"programmer\" (1), \"camera operator\" (1), and \"futurist\" (1). Ages ranged from 20 to 52 years old, with an average of 32 years old. Fourteen respondents were male and seven were female. We collected responses from several nationalities, but we did not record the country of origin of the respondent. Expectations Regarding Content and Interactions  
Ten respondents mentioned the use of video or 3D models in the cover of the book as a way to present a summary of the book's contents (\"... the author, in videochroma, presenting the work.\"). In general, respondents' comments' pointed that dynamic content should be used in the cover as an attraction factor (\"A cover with animation makes the book more appealing to the reader\"). One respondent suggested that the book could trigger content outside of the book itself as a way to take advantage of the 360\({}^{\circ}\) space around the user (\"... the opportunity of seeing in 360-hence, the reading experience of a book is no longer focused...on the pages and becomes an immersive experience\"). One respondent suggested allowing users to choose the book's layout in the cover page. This suggestion was probably inspired by current ebook readers that allow selecting the book's layout (e.g., one or two columns). However, our Tangible VR Book was not intended for high-density text display and so this feature does not currently seem relevant. Regarding the interaction with media content (all respondents focused on video), six respondents suggested automatic video reproduction. Some participants explicitly mentioned playing automatically as the page becomes visible, other suggested playing only if the video (page) is brought closer to the user. We found it interesting that this respondent suggested this kind of interaction given that we implemented a similar interaction for the portals.