I was wondering how to blend materials to get a nice look to my meshes. At the moment they're looking like: 
as you can see at the top, the dirt material doesn't blend with my grass material. Is there a way to do that?
PS, if there is a way, if I export this mesh to ue4, will it still have the gradual material?
Thanks, Max
There is a way to do this using BI Nodes. As for the exporting, I don't know. Here is the final result:
Add two materials to your plane, a dirt and a grass. Assign the dirt material to the top of the plane. Make sure the dirt material is brown/black, and the other is greenish. For the grass texture, click the nodes button:
Go into side orthographic view, Tab into Edit Mode, key U to open the Unwrap menu, and select Project from View (Bounds).
Go to the Properties panel > Textures tab and add a new texture. Set it to Blend. Under the Color dropdown, check Ramp. This will control how much brown vs. green there is, where it fades, and how sharp the fade is. Under the Blend dropdown, choose Vertical. Under the Mapping dropdown, set the coordinates to UV and select the previously created UV Map. Make sure nothing is checked under the Influence dropdown.
Open a Node Editor. Use the following node setup.
Here is the .blend:
For the use within Blender you could go with vertex colors. Just Tab into Vertex Paint mode, choose a color and paint away. However, to use this in any RT engine you need to bake the vertex colors to a texture.
Max, whether or not your blended materials will export to UE4 depends upon how UE4 is designed. Most game engines do not presently support cycles render, so it is possible export will not work.
