probably a simple solution but cant find a way.
i have a repeated texture and want to paint a different texture onto it as shown in this blend file TEXTURE PAINT TEST.blend (569 KB). however when i paint it gets repeated like a grid on the texture.
how can i paint only on part of the object and not get it to repeat everywhere?
Make another uv coords. Leave the first one, let it do what it is doing and click ‘+’ near where uv maps hide in interface. Name, make another unwrap, could use just needed faces e.g. Use in cycles - add Attribute node. Blender internal render will allow to bake combination on a new image; a lot can be done.
Another thought - do you actually have uvs on your object? If not then you need to start adding them.
i’m not sure what you mean by “do you actually have uvs on your object?”
isn’t that when you unwrap an object? if i am mistaken can you direct me to a good tutorial?
Exactly, UV coordinates (uvs…, beg your pardon) are created if you unwrap object. I saw you mentioning “repeated texture” - that happens when each face takes all UV coord space - You could do UV unwrap - command “Reset” and say for a default cube all faces lay on top of each other in such unwrap. As a result each face gets whole image assigned - you have repeating texture. Or your uv unwrap is sized bigger than grid space in UV Editor window - you also will get repeating texture. If your uv unwrap is in the grid space it covers image you supposedly created and paint - no repeating should occur.
I should have looked in your file which i did just now - your unwrap is scaled larger than grid space; that’s why you see texture repetition. After unwrap it’s a good idea hit menu UVs - Average Island Scale and UVs - Pack Islands wich automatically brings unwrap into the grid space.
As a result texture image you have will cover all object which you might or might not want… This time your image is 398x398 pixels and it is not tileable which means result will be very low resolution for a whole object and you saw already what happened when it was “tiled”. While it would work on a bathroom wall or flor (with appropriate image) this does not work on a landscape.
For a new start i’d suggest clean file, new object, make UV unwrap (doesn’t really matter what type of unwrap you use for a test plane)
and next, create new image in UV editor; choose size not less than 1024x1024 pixels. Your unwrap will automatically be in the image.
Now you can start to use Texture Paint mode.
By default image created is black; you could choose your own color - basis to start with. If you want you can use your initially used image as a texture for painting - Texture paint Stencil mode allows to position, scale and rotate image, if you brush over it ‘stencil image’ will be painted on before created texture image.
Do not forget to Save image you painted in UV editor window menu. It is not saved automatically when you save blend file.
For the tutorials - either Blender Cookie Members or Google “texturing landscape in blender”. One of my favorites is http://vimeo.com/5667694. It might look over a top at first and is not for latest blender version; nevertheless all needed is there; including a lot of other useful things.
thanks for your detailed explanation
firstly, the blend file i uploaded is just to give an example of what i am doing. my original file that i am working on is around 150mb
i scaled my unwrapped model in the image editor since the texture is too big when put on a landscape model and small stones will look like boulders. i dont mind having the repeated texture since the model is going to be viewd from far away but i only want to paint certain areas with a different texture
for example i’ll have a repeated texture of grass for the flat areas. then i want the sides to be loose rock so i’ll paint the texture on the model, but the loose rock get painted on every tile of the grass texture.
hope i explained better. i’ll have a look at the video tutorial later since i am bit pressed for time but i will post back when i’ve seen it and understood something 
Then you definitely need to look for how to use mask painting - using 3 or more textures one on top of each other; how they “overlap” is determined by so called mask texture - grayscale image where white reveals and black covers visibility of two others.
There is one more advanced way of doing this, check it when you’re done with previous method.