How to render Quake 3 volumetric fog

Thanx for the interesting link,to hear from the “master” himself is alwasy useful.
But my real problem is that I don´t know if my assumptions about the bsp format are really correct:

As far as I know there are four vars which deal with vert information in the face-struct:

vert: -and index to the vertex array,
this is the first vertex in the
face.

num_vert: -this is how many vertices the
poly has

meshvertex: -an offset to the first
meshvertex of the face in the
meshvert-array(the values in the
meshvert-array is an offset
in the vertex pool again?)

n_meshvert: -this is how many meshverts the
face has

So my question is:
What is the difference between them(verts and meshverts).It looks like a poly which is declared as “poly” has some value in ALL of these vars(makes no sense,why has a face declared “poly” meshverts in it when there are faces declared as “mesh”?).
It´s the same thing with “mesh” declared polys(the have verts and meshverts).
Does this mean I can ignore the values in the meshvert-vars if the face is declared
as “poly”?
And what exactly is this mesh,the models like skulls…? And how do I interpret it(I currently draw the mesh-polys by drawing a poly through all vertices mentioned from meshverts[face´s first meshvertex] to meshverts[face´s fmeshvert+n_meshvert] ,but this looks wong)?

P.s.: Don´t point me to some source,´cause to find out these things from the complete code is usually a little complicated,I think.

Sorry for asking so much things but please help me,XBTC!

[This message has been edited by XBCT (edited 06-05-2000).]

[This message has been edited by XBCT (edited 10-15-2000).]

Hello, So do you know how to do the volumetric fog if yes can you share the information with me? And while we are on the subject of Quake3 does anyone knows about How quake maps work in reference to rendering and lines that are not drawn?