Each of the lines corresponds to one particle. A one or two - character string is used to label each particle, for instance 'O' or 'Al' at the example below (Aluminium oxide) denote different atoms. The labeling allows assigning different properties like color and size to particles designated by different strings (more details). The following three floating point numbers represent the x, y, and z coordinates of the particle. Up to eight additional floating point numbers can be provided. These additional numbers can be used to visualize properties such as velocity, energy, etc. Here is a short example for an xyz file (used for atomistic visualization) with one additional column of data:

6
## Aluminum oxide
O  -0.083333 0.250000 0.583333 0.433013
O  0.083333 -0.250000 -0.583333 -0.433013
O  0.250000 0.583333 -0.083333 0.433013
O  -0.250000 -0.583333 0.083333 -0.433013
Al 0.583333 0.583333 0.583333 1.010363
Al -0.583333 -0.583333 -0.583333 -1.010363

In the case of spins visualization, xyz data files consist of minimum six numerical columns. For a better understanding, at first, give a brief glance at
this example (xyz file representing spins located at sites of a 3D 6x6x6 cubic lattice).

The first three columns represent the x,y and z position coordinates of the spins. The numbers in these columns should be integers, since spins usually are located at cubic lattice sites (of course, if required, non-integer coordinates can be provided). The additional three columns are needed to specify the orientation of each spin. The fourth to sixth columns specify respectively the x,y and z components of the spin inclination.

Very important: even in case one wants to visualize a less than 3D array, one still should provide three columns for the position coordinates (for less than three columns of position coordinates one will get the wrong visualization). One can write any constant value for the coordinate that doesn't change. For instance, when visualizing a 2D spin array one can choose the z-position column to be a constant value, like in this example (xyz file representing spins located at sites of a 2D 12x12 cubic lattice).
Also, the order of raws doesn't matter,but blank raws must be avoided.

Another type of file that is read by Aviz is a List file (example). Such a file is actually a name list of xyz files. When opening such a file, a small control board will pop up that lets you cycle through these files, in single steps or continuously (more details).