From mobile phones to display walls, graphic terminals are taking a more and more prominent place in our everyday-life. The increase of the computational power of recent workstations and the progress in virtual representations now allow us to send data from both large data base and complicated data structures via heterogeneous networks. Hence, it becomes fundamental to provide virtual data with intuitive modeling, accurate representations, progressive transmission and interactive high-quality visualization in order to exploit the full capabilities of the different devices and networks.

Among the data that one would aim to represent, our environment is certainly the most obvious. It surrounds us and any realistic virtual representation should reproduce it faithfully. Elements of our environment like the cities, the forests, the mountains or the sky have been well studied. Nevertheless, the proposed models are so diverse that they are difficult to embed in an unified framework. The lack of this integrated framework slows down the development of virtual reality applications (both professional and general use software) and also leads to an under-use of the available technical ressources.

In this project, we propose the study of natural scenes through vegetals (trees, forests, prairies), watercourses (rivers, rivulets, waterfalls) and clouds (clouds, mist, fog). Despite a growing interest, this emerging research topic has yet received little attention. On one hand, the botanic, biologic and physics communities acquire and store huge data sets representing each single natural entity with a dedicated model. On the other hand, the user community is willing to smoothly navigate in realistic virtual environments or to easily create complex virtual landscapes. In between lies our project: treat this huge amount of data in terms of data structure, techniques and algorithms, in a unified framework able to adapt both to the content (e.g. the internal representation) and to the navigation context (e.g. view point, devices etc.). We will hence focus on the models, the evolution, the adaptive transmission and the visualization, but also on the composition of several natural entities in a complex virtual environment: sailing along a river flowing in a glade of luxuriant grass, swaying under a light wind, in the middle of a forest of many tree varieties, under a bright sun; but also under a pouring rain, in autumn, in springtime, in the fog, at the tree plantation or some decades later, etc.