Hi Friends
Recently in an aircraft texturing tutorial I come to know that you can use same bump map that you have made for the aircraft can be used in diffuse and specular color channels???But I know that in diffuse channel you put your painted (I mean the painted color texture) and in bump channel you put the bump map?so what effect one has by putting bump map in specular channel?or is there any other channels that can be used also,this is totally new topic for me,any tut that explains it will be helpful too.
Thanks for your time.

If you put the bump map in the Highlights (the name of Specular in Vue) the effect should be to disperse the highlights, to make the highlights to follow the bump. That is common practice with noise or fractal nodes for bump but I never saw it done with bitmaps. However, I have seen different bitmaps applied to bump and highlights.

Anyway, if you want to do it, go to the Highlights tab of the advanced material editor, check "variable highlights", right click on the "highlight production" function that will appear as consequence, chose "edit function". You'll go to the function editor. If you already have the bump map applied, just connect it also to the highlights node, greyscale output.

To load in a map for diffuse lighting, you need to click the little "lighting bolt" icon next to the diffuse channel, in the effects & lighting tab of the advanced material editor. You will then land in the function editor. Click the image map node on the left side of the window, and connect it to the diffuse output ' delete the constant node attached to the diffuse output first), then load your image map.
I think you need in finite for this, but I'm not sure.*
The result will be the diffuse lighting will appear on the lighter & white parts of the diffuse map, Darker and black parts will be illuminated by the ambient lighitng.
To avoid having your object using more than 100% lighting ( diffuse+ambient), load the same map in the ambient slot, but invert the image. If you don't do this, the object using this material might become luminous, which can be a problem when using advanvced lighting models.

I link my texture maps to bump and highlight maps, for quick nice look, unless I need a more precise set of maps ;)

Read my tuorial on poser imports (in my signature) and you'll see that trick, it makes a much nicer look and saves resources
:)
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Thanks a lot guyz for your time,just to make things clear I have one more question:
Texture No.1
I am going to paint a basic color texture that will have color,markings,text on it .
Texture No.2 
and a bump map which will have panel lines and rivets on it.
 
Now can you tell me to get a good looking metal feeling which texture should go in which slot?plus do I need to invert or not?

I know metal shader plays an important role but right now I am more interested in learning to get max out put by placing the textures in different slots.
Thanks a lot for your time.Once I will understand this I will put textures as per your advise in different slots and start playing with the settings.

Quote - Thanks a lot guyz for your time,just to make things clear I have one more question:
Texture No.1
I am going to paint a basic color texture that will have color,markings,text on it .
Texture No.2 
and a bump map which will have panel lines and rivets on it.
 
Now can you tell me to get a good looking metal feeling which texture should go in which slot?plus do I need to invert or not?

I know metal shader plays an important role but right now I am more interested in learning to get max out put by placing the textures in different slots.
Thanks a lot for your time.Once I will understand this I will put textures as per your advise in different slots and start playing with the settings.

Vue has a peculiar habit which is the opposite of EVERY other app there is, of inverting the way the greyscale map is applied ot bumps etc, don't worry about it, there's an icon in the material edtor which you can click at any time to invert an image :)

So just do it as normal: black = minimum, mid grey = baseline, white = maximum

Bump map has to be different when you it up close, lot of special detial etc, it's up to you to decide if this is necessary, it's a judgement call.

For say, a spacecraft or tank hull with obvious rivets and panel lines it will probably be necessary to make a seperate bump map.
If it's for very high detail and precision a seperate specular map may also be necessary, bu that's IF you are going for ultra precision!

Do nto worry on specular maps if this is a 1st project or it's not going to be incredibly precise.

Again this is an uber tutorial!:
http://forums.cgsociety.org/showthread.php?f=46&t=373024&page=1&pp=15

Your colour map goes in colour channel, greyscale bump into bump channel (bump can also drive Displacement if you have Vue Infinite)
:)