Usability of web-based VR - 3D format

One of the most basic and difficult questions is what 3D format to select, for several reasons:

• Candidates: there is a large number of alternatives, ranging from VRML and its successor X3D to proprietary formats like Cult3D, QuicktimeVR, and Shockwave.
• User aspects: for each candidate one has to check how many users already have the corresponding viewer installed, the download size of the viewer and applications, the quality of the rendering engine and the usability of the viewer.
• Development aspects: the availability, usability, and flexibility of development tools as well as the availability of support.

In taking all this into account, one needs some clairvoyant's skills, to avoid that one backs the wrong horse - both with regard to the imminent project requirements (Will we be able to realize the planned features of the application as well as future ideas and supplements?) and the life-time of the application (On the background of the rapid development of 3D and VR technology, is it possible to adapt our application to the respective state-of-the-art?).

In retrospect, we have the impression that we backed the wrong horse in our first eLearning project, in which we decided to use VRML, but were rapidly disappointed about the stagnation in this community, especially with regard to viewer quality and flexibility. In the second project we decided to use Shockwave, are still quite happy with this decision, and hope that we will not be disabused by future developments in this field.

In planning the realization of a VR application, one should consider streamlining it by sourcing out certain elements. Jacko et al. (2000) found that users may prefer highly graphical web sites, but are rather unwilling to tolerate substantial delays. Another aspect is the performance of graphics boards, which together put constraints on the complexity of the content and thus the degree of realism.

One opportunity for outsourcing is the presentation of textual information. Inserting longer texts commonly results in poor readability, especially if one selects a higher compression, to keep the download of the application within acceptable limits. Under these conditions, an alternative is to present the virtual environment and the text in different frames, as shown in the example below.