In spite of the large range of morphologies observed for biofilms, there is strong experimental and theoretical evidence that the complex nature of biofilm structure dynamics is primarily a consequence of the effect of environmental conditions on biofilm development. It has been observed from the operation of industrial and laboratory-scale biofilm reactors that the structure of biofilms results from a balance of the detachment forces and the regimen of transport of a growth-limiting substrate. The overall performance of biofilm reactors is intrinsically dependent on biofilm morphology. The spatial distribution of the diverse dissolved and particulate components through the biofilm matrix and the shape of its external surface influence the rates of the occurring bioconversions, and structure also influences the stability of the biofilm in terms of resistance to mechanical stress. Individual-based modelling (IbM) of biofilms structure dynamics is used here to unify observations from the operation of biofilm reactors by simulating biofilm growth under variable detachment forces and mass transport regimens for a growth-limiting substrate. The IbM is a bottom-up approach, where the global system behaviour is derived from the local interactions of multiple elements acting independently. Transport and reaction of a solute species, local microbial growth rates and the effect of external detachment forces applied to the biofilm are modelled using differential approaches. Simulations carried out in two-dimensional space using this model illustrate a range of biofilm morphologies that emerge from different reactor operation parameters, reproducing trends observed experimentally. Comparison of multi-dimensional modelling results with those obtained using one-dimensional approaches enforces the need to use multi-dimensional modelling to predict properties that derive from the spatial biofilm structure.