One of the cool things about Blender (besides being free) is that it has some pretty good tools built right in for texture painting and texture sculpting.  I don't claim to be a master at this, but I've found a couple of videos that have helped me along.  These are all YouTube videos.

This first one is a "quick tip" that is actually almost 40 min long.  It covers various types of texture painting in Blender, some important settings (like Bleed), using images as stamps and so forth, and then goes into using images and textures in mesh sculpting.  Lot of very useful info.

Using Brush Textures in Blender 2.67+

This second one covers more on texture painting as well as guiding you through a complete project creating a low poly brick wall.  It covers one other useful option in Blender, baking a high poly model/texture to a low poly mesh. 

Creating a Grungy Brick Wall in Blender

And this last video is not a tutorial, its just a time elapsed recording of an artist's work flow as he paints a game sword in Blender.  Pretty cool results and though it wasn't intended as a teaching video I still picked up a couple of tricks just watching it.

Hand Painted Sword Texture in Blender

theres a couple of addons for texture painting

one gives you layers and the other is some "better" brushes

just thought I haven't put them in 2.68 yet!!!!! doh

will check they work an post links

The "Texture Paint Layer Manager" Add-on came pre-installed in 2.68a; was that the one you meant?   Don't think I got any extra brushes, will have to look for that.

Look at what is coming: http://www.youtube.com/watch?v=ZtZwYhHpdzg&feature=player_embedded

Good share!

I have been using Blender to make a cave setting for poser. I have been using texture painting with stencil in hope of removing apparent seams between uv islands/clusters. However when I paint over the seams it doesnt remove them the texture seems to be slightly offset on each side of uv seams. I can camouflage it by adding a lot of different colour but it's still there. I dont understand because the stencil should add pixels on each side of the seam in 3d view as if there was none and I have been trying different "bleed" settings to see if it made any difference ( it doesn't ) I tried relaxing the uv maps a bit with uv sculpting tool but it doesnt make a difference. Could it be a setting in the texture brush options or in the texture panel?

Thanks in advance if anyone has a solution for this problem

did you use the "smart unwrap" ??  if so try setting the island margin a little higher

I have found that it can pack islands too close

A screen shot would be really helpful, a picture being worth a thousand words.

When using smart unwrap I generally use a setting of .o6 to give enough space between the islands.

Actually no I mark edges as seams and then I use the basic default unwrap. I will look up for the island margin setting. 

Thanks!

think the island margin only applies to smart unwrap

since you are using seams any chance of "hiding" them in a corner ?

I normally use default unwrap and then sort the UV Map according to what I want.  Using material groups you can also use a sort of "hybrid" method using default for some parts, cylindrical for other parts (there are certain cases where this is really useful).  Smart unwrap is its own thing however and while it makes very efficient use of map space is virtually unusable in a 2D paint application (it generally breaks the mesh up into a lot of small blocks and arranges them in the most space efficient manner, which generally makes it very difficult to paint on in a 2D app later).  I normally use smart unwrap on a hi-res sculpt where I paint directly onto the object mesh within Blender; and use other unwrap methods for my final model.

On the Bleed setting, I find that a setting of 8 generally gives me good results.  However, if I still get a visibile seam I may open the texture map and paint directly on it within blender.  I'll use the eyedropper to get a sampled average color of whatever texture I'm stenciling and then use a brush to feather that in around the edges of the islands.

Another thing you may want to try is doing a split window (or if you have dual monitors, open a second instance of Blender on the 2nd monitor) so that you can watch the UV Map while you paint to see how your stencil is being applied.  Sometimes that gives me clues as to what might be wrong (maybe I need to adjust my seam or move the islands on my UV Map, etc.).  You can even use the stencil directly on the UV Map in some cases to touch up a problem area.

BTW, if you don't have a 2nd monitor but do have a HDMI 720i or 1080i TV, you can get an HDMI cable and use your TV as a second monitor (which is what I'm doing).

thank you all for your contributions. I changed to cycle renders and soon after that  I realized that moving viewport camera away from model removed the offset..  (???)

Now it's about all clean except in one place where a narrow path leads to a big cave.  Also I have noticed that when I use the texture paint across seam (using a dark texture over a white background) sometimes it leaves out white spots near the seams and I have  to paint it from a specific angle to remove the spots.

Strangely enough I exported model to poser and I had white seams in preview window everywhere I changed settings and the seams tended to disappear when moving towards the polygons. I have restarted Poser and the seams have totally disappeared...

thanks for your suggestions.  In the future I will try using smart UV as you pointed out. it seems a very effective way to use texture painting. any idea if it's also useful when baking normal maps?

Sometimes the filters blender applies to the textures at render will blur the edges a little further than you would prefer.

I see.. so that explains why what I see changes with distance..

I see.. so that explains why what I see changes with distance..

I see.. so that explains why what I see changes with distance..

Darqmind... I think that's why there's a bleed setting. If your maps are too tight, some effects will blend in stuff from the edges. Bump the bleed up a bit when texturing to get more overlap and make sure there's room between non-adjacent UV charts so you can do that.

As for texturing in general in Blender, anyone got an anser for this?

http://www.youtube.com/watch?v=ENS6QQZIsgk

Only anwser I could think of is having a side project where I join the parts that share a map in order to texture paint the model. (Remembering not to save over the other project where the parts are all separate as they should be.) If only I could do what I wanted to, it seems like that shouldn't be necessary.

Unfortunately, I don't know of any other way of painting across seperate objects except joining all the objects/UV's into one.

I usually overcome this by creating vertex groups for each of the objects before combining to make selection easier both for the UV Map and when it comes to seperating everything again.

Your solution though seems to be a better one as the seperate file would allow everything not to be painted to be deleted which may make things a lot easier. Will have to give it a go.

Yes I wish there was an object level in edit mode to quickly select joined object but both your solutions seems very valid.  Just curious though.. is the smoothing wrong when object are joined? I mean the vertices are not merged right? that's something I have yet to try.

Smoothing shouldn't be affected by joining and vertices will not be merged. The only thing to watch out for is un-applied modifiers that can cause unexpected results that may not be immediately obvious. (Mirror for example).

Verts will not be merged unless implicitly told to do so by selecting and remove doubles.

Ok thank you. By the way Is there a way to quickly select an object after it's been joined to another?

CTRL + L will select the mesh underneath the cursor.

If you want to select all the meshes that make up one of the objects that has been joined in one go, then it would be better to create a vertex group of the complete object before joining.

If you add any further meshes/verts to that object don't forget to add them to the group.

Funny you mention joining and such...

When I UV'd and charted the model in Wings3D (I still model meshes in Wings, it's faster for me), I had different pieces joined in order to share the same maps for multiple parts. But separated everthing again afterwards. That way all the textures for adjacent parts can use a common map as their UV coords from the mapping process are retained. Keep in mind each part being separate makes mechanical models work easier for rigging, etc. (Something also seen a lot with game models.)

But regardless of how they're mapped, I still wish there were a way to paint textures on multiple parts by some group selection in Blender. (Without any need to join meshes.) Such a thing would definitely save time and improve workflow.

For now, texturing in a separate file with all the parts joined does seem to be the fastest way. Since the UV coordinates are the same for the model in both files, the texturing and resultant imagemap done on the one with joined parts will work just fine on the other where the parts remain separate. (More process to get stuff done, but ideally it shouldn't be necessary.)

Thank you again for the precious information Touchwood :)

By the way I have another question about Blender. WHen I use materials I select "use nodes" but in the node editor there are no nodes except for rendering. Is there a way to make the nodes corresponding to the scene materials show up in the editor?

To Paul: I have yet to try wing3d. Which one do you prefer? how good does it stand compared to Poser?

down at botton of node editor is some icons  hover mouse over and they say whats what (if you have tooltips on ) click on shiny ball then on cube

@Paul why dont you model in blender mate ? (not knocking wings it was my fav once )

For material nodes press the checkerboards icons.

In cycles you will get tha basic setup, diffuse and output. With the internal renderer, the screen is blank and you will need to add them manually.

ok thank you :)