Texture painting Q:

When stenciling and texture painting, how do you select the texture to make it active, the one that you want to paint on?

uv image editor.

To Texture Paint

  1. Select Your Object
  2. Split the window into two panes
  3. Set the new window to UV image editor.
  4. Select a texture or create a new one.
  5. Press Texture Painting Button

To make the texture active, just select all the faces and load/select the texture you want active in the UV/Image editor

Just make sure that the terrain/object is always UVmapped to the stencil you are currently using.

Heres and example .blend: http://www.mediafire.com/download.php?1wzulmmyamm