Hi there. I am willing to plot a function of three space variables plus time, lets say ##\phi(x,y,z,t)##. The idea is to plot the 3D function for each time, i.e. evolving in time. As I have three independent variables, corresponding to the three Cartesian coordinates, the function is actually a four dimensional object. So, the idea I had in mind was to plot the mangitude of the function with colours and transparencies, in such a way that I can see through the 3D space. As ##\phi## represents some diffusing concentration, I would like to see it in the whole 3D domain. If possible, I would like to do this with gnu plot. I have already plotted functions of two space variables evolving in time with gnuplot, but that is much easier. However, if somebody knows of other alternatives to do this, I dispose of the data in columns, in a text file, x,y,z,##\phi##,t. If there is some software to do this in an easy way, I would welcome it (preferably in linux, but if it is for windows, I can arrange my self to do that).