Image: Individual-based model biofilm
Biofilm, aged 96,000 min (67 days, 9.5 weeks). The contour lines show the oxygen concentration in mg/l. The image was rendered with POV-Ray, showing each cell as a sphere. The ammonia oxidisers ("Nitroso") are green; the nitrite oxidisers ("Nitro") are red. The grey box at the bottom is the inert substratum. Note the wrapped around boundaries in the horizontal direction.
In the Individual-based model, cells are spread independently of each other. Cells are spheres rather than bricks and exist in continuous space rather than on a discrete grid. However, this leads to less mixing since the spreading mechanism is not random but deterministic.