Using the mia_material_x in mental ray, I created three virtual surfaces that mimic a banana, orange and apple. It was difficult and took quite a bit of time to produce a result close enough to these surfaces, but overall, I am happy with the results.
First off, the banana was a difficult surface to mimic as there are several slightly different colours within its surface. The bruises were especially hard to recreate as I could not make them as large as I wished. A ramp was placed into the color of the mia material. The ramp consisted of several colours that included yellow, brown and black. A fractal was then placed within the black to get the look of the bruises. Finally, a bump map with a noise surface was placed within the surface with a bump depth of 0.05
The orange was far more simple. A fractal was placed within the colour of the mia material and the default colour and colour gain were made orange. Next, a fractal bump map was placed on the material with a bump depth of 0.05. Finally, the glossiness was put to 0.390 in the reflectivity menu of the mia material.
The apple was created using an mia material with a ramp set into it’s colour. The colours were red and yellow that striped down in the U ramp. A noise bump map was the produced to recreate the unevenness of the apple’s surface. It’s bump map depth was set to 0.05. The reflectivity of the mia material was set to 1 and the glossiness was set to 0.416.