Good info: thanks ! 

Had anybody ever used a simple vine texture with a background that can easily be made into a transparency? I'm generally unlucky in finding good texture repositories. Drooping vines, or anything close, would be really neet-o. 

Check http://www.quaddicted.com/wads/ there are tons of texture set there ;)
Make your choice 

For some strange reasons all textures that I apply to surfraces are mirror images (x-axis reversed). Why and how to revert them? (Worldcraft 3.3) 

where it says texture size x and y, change it to -1 instead of 1, or whatever you have in there, this will reverse the texture on the axis you chose. 

This is my first real attempt at terrain in Quake. But it appears that what I do in the editor is not reflected in the game.

For example, here is what I've done as seen from the editor:

http://www.esnips.com/doc/6f4642d4-1fe9-43d7-aa48-6f9b83e9ce60/editor

And here it is in the game:

http://www.esnips.com/doc/8f91108f-6713-4aa8-b2de-eb27253a6d07/quake11

You can see the edges/verts aren't connecting in the same way as they are in the editor.

I'm guessing it's a problem with the compiling tools? This screenshot wasn't VIS'ed, but on a brief previous attempt at terrain, the same thing happened while the map was fully VIS'ed. 

You're most likely making concave geometry in the editor and it's being moved to the nearest vertex to make it non-concave upon compile. It used to happen to me when I'd try to skew cylinders to make rocks.

Your best bet is to tri-soup that badboy like this:

http://www.snarkpit.net/editing.php?page=tutorials&game=HL&id=16 

Chop it up into Five (wedges) or four sided shapes (pyramids) and you'll be good. For overhanging stuff I'd recommend pyramids, but it's more work to keep everything together. Wedges work best for floors; it's easier to keep them neat and without leaks or holes.

Also, you've moved over from Q2 mapping? Good to see you here. 

These errors have shown up because I was using rectangle brushes?

I think I tried using triangular brushes previously, but found it more difficult. Guess I will need to practice that. I know the method, just a case of trying to get it to look good!

ijed: No, I was into Quake mapping 10 years ago, but never really finished anything. I've made a few maps for Doom2 in the last couple of years but ended up getting frustrated with the limitations, so came back to Quake. 

go for wedges, ie a 5 sided brush, bottom and top are triangles. Bottom, top, 3 sides.
A triangular slab so to speak.

Then just always look at the brush from the top, select a the slab's corner vertex/endpoint, both the top and bottom vertex at the same time, and move that unit together. One corner of the slab. You can move it sideways or up and down too.

As long as all the three corner vertical edges of the slab are vertical, it stays as a legal brush where it's convex and all the sides are planes.
I made a pic ages ago but it's lost in some of those pic upload services, maybe searchable in this thread. 

where i can send private message to users? 

You can't. This is a public message board no "communication service". Use e-mail. 

...right? 

You know you could check the user in question's profile and see if they have their e-mail posted or simply just say who it is you want to contact and someone could probably help you out if it's a current user. 

Hold n while dragging a vertex, sex! I never knew. 

What does it do? 

instead of dragging a whole "border" of a brush.
http://shub-hub.com/files/images/vertexdrag.jpg
http://shub-hub.com/files/images/linedrag.jpg 

Just push "vertex tool" a few times. 

Ahh OK, thanks! I see that it triangulates the faces when you do that. Is that automatic? 

Assuming you have the 'vertex editing splits face' option on, anyway. It'll triangulate a face if you edit verts in such a way that the face is no longer planar. (It will also automatically un-triangulate (quadrangulate?) it when you move it back to a position that does create a planar face again, I believe).

It's a a nice feature! :) 

It is also possible to press n and rmb on it and force the vertex to the grid. Otherwise Quark sometimes moves other vertexes. And even then when you look at the .map file with a text-editor it's a mess too many dezimals. Vertexes that should be on grid because forced are not. That's (apart from the bugs) a reason why I switched to bsp. I couldn't finish a map with QuarK because I struggled with Hom effects as the map got bigger.

untriangulate does not really work in Quark. it results in invalid Polys or moves other vertexes. 

Oh indeed. And I thought I set the right settings this time (no floating point, Quake map format). Gah! 

Trying to explain but words are failing me...
(in a hurry)
You know in halflife you get those wire fences, and grills/grates etc, also stuff like vines and sometimes hanging cables which are made from brushes using textures which are fully opaque, except for one 'colour' which is fully transparent (i believe in the HL Quake Wad its a sort of blue colour)?

Can this be done in Quake?

Im thinking JPL is doing glass, Trinca did some in Wicked Base etc, but what I mean wouldnt be like that (func_wall with ".alpha" key).
I seem to remember one person say "why has no-one done this for quake yet, cause a lot of modern engines support it"

Does anyone know what I mean, or even better how to do it, i.e. what colour in the palette is "invisible"?

(I always thought it was funny in Halflife cause say the fence brush was 4 units thick, if you stood on one side then the other you could see the fence move four units cause the nearside of the brush would be the only visible side)

DOUBLE HARD QUESTION - I CHALLENGE THEE TO HELP!! 

You mean like this?

http://kell.leveldesign.org/screenshots/ss-grill.jpg

It's done as a sprite, instead of a texture, but it's pretty damn close.

It's in the next Quoth pak. 

But isnt there a way of doing it with brush-models?