Advantages and limits of the representation.

The light intensity of the computed image is the only information provided and cannot be used to differenciate the value variation and the volume depth. For instance let us suppose that we want to visualize a temperature field: for a constant volume depth, the lighter the area appears, the higher the temperature will be, but for a constant temperature, the area will appear lighter if the depth of the crossed volume increases. It is therefore very important to be able to remove these ambiguities. We have found that considering the volume under different points of view is an efficient solution to this problem. Therefore the volume rendering is usually associated with an animation tool to consider the data from different points of view. Note that this implies to compute for each visualization several volume rendered images.