[MUSIC] As with everything else in user interaction, when it comes to your chosen solution and implementation of navigation in VR It is very important that you evaluate it with the targeted user group of your application. I will now take you through a few things which are important quality factors you might wish to use in your user evaluation. They are adapted from a paper by Bowman et al., from 1997 and these factors help us understand how similar the virtual travel is to real physical walking, which is essentially what we're trying to simulate here. First, speed, how much does the user have a sense of control over the speed of travel? Note here, it should be about the sense of control rather than the actual control. Sometimes the user might be assigned a constant speed, but if this speed is well chosen and really works for the specific application, then the user will have a better sense of control. Comparing to actually having direct control of the speed but in a very awkward way due to, for instance, limitations from their hardware. Secondly, accuracy, how accurately is a user able to arrive at a desired target? How likely will the user overshoot the target? The next factor is spatial awareness, the user's implicit knowledge of their position and orientation within the environment during and after travel. Did they get disoriented during travelling? Do they have a good sense of scale? After exploring the VR scenario, can they draw a accurate map of the virtual world they visited? Next factor is ease of learning. This is something easy for an novice user to use. How long will it take on average for the users to get the hang of it? You might also want to evaluate the method in terms of ease of use once the user has learned the technique. How complex it is for them to use it? What is the cognitive load from their perspective? Another factor to consider is information gathering, which is the users ability to actively obtain information from the environment during their traveling. Trying to find all of the objects they need to find during their experience. After the experience, can they remember objects they saw in the virtual room? And a very good overall evaluation would be presence or place illusion and plausibility illusion. Do they feel that they were really somewhere else, and was the experience engaging and plausible? Last but not least, how comfortable is the experience? You might have designed a virtual travel technique that ticks all the other boxes but if it makes a user feel sick, then it's unlikely they will enjoy it. You don't need to use all the quality factors listed above. Often it is a good idea to select a subset depending on your application. For instance, if your application is a architectural walk-through where the users can navigate a building before it's built, it is important for them to have high level of spatial awareness and certance of place illusion. However, in a action game, speed and accuracy are more important. [MUSIC]
