{'fraction_non_alphanumeric': 0.013220518244315178, 'fraction_numerical': 0.0010576414595452142, 'mean_word_length': 6.059701492537314, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Viewpoint adaptation during navigation based on stimuli from the virtual environment

We consider the possibility of automatically modifying the user's viewpoint orientation for the purpose of enhancing the navigation experience. We concentrate on outdoor virtual environments where the terrain is uneven as well as certain cases of indoor at environment floors, respectively on environments where focus-drawing objects and different types of obstacles exist. Most natural environments present these properties and virtual environments that are based on natural environments are in abundance. The navigational adjustments are introduced as response to environment stimuli such as slope changes, the emergence of visibility rays to focus objects or as navigational difficulty events occur after encounters with nonoversteppable obstacles. A scheme is presented that facilitates the viewpoint orientation feature. Conceptually, the viewpoint orientation is a method of partially and temporarily decoupling the head movements from the navigation direction. Virtual environments in general and their encoding in VRML, X3D, Java3D as well as other scenegraphs are analyzed to reveal bottlenecks in current scenegraphs that make the implementation of such automatic adjustments from difficult to impossible, needing custom navigational code where possible. Different scenarios are presented, where these adjustments can prove useful by speeding up the navigation and providing a higher quality, richer experience. Additional to relevant literature, further experiments are necessary to analyze the effect of automatic view adjustments on the user's immersiveness experience and direction sense (path finding), experiments which could be carried out using custom navigational interfaces incorporating head movement extensions separated from the navigational data, extensions proposed in this paper.