Computer graphics are commonly recognised over realistic images because of repeating elements. In this sense, randomness usually adds an added level of realism to images. This is a method to randomly apply mapping of textures in objects. Beware that this only works with individual objects. This means you are left with a floor made of 1000 stone blocks, in which each stone is a separate object.
The trick here is to modify the vetor mapping with a Random number issued by each object. Of course this method is only good if no particular location for the texture is needed.
Following, 3 images. In each of them, you can see a rendering in which a top row with three objects use the same mapping, and the bottom row uses the tweaked mapping to achieve randomness.
- Example with Blender's default testing image.
2. Example with our test texture
3. Example with a common wood texture.