
262 Virtual Reality: Concepts and Technologies
Properties of colour, light or transparency can be used for emphasizing certain
elements. For example, reference points can be highlighted using one characteristic
colour. The use of variable light sources can help the observer in his movements.
Primarily, significant lighting of communication channels in contrast to poor lighting
of impenetrable zones makes it possible to help the observer in his choice of movements.
Numerous other software aids can be incorporated into virtual environments,
depending on the characteristic of tasks to be done. These aids can be visual, but may
also use other sensory