1. A method comprising: determining that a deployment topology model is semantically correct in accordance with semantics of a modeling language as defined in a modeling tool; traversing a data representation of the deployment topology model, wherein said traversing comprises selecting an element of the deployment topology model as represented by the data representation of the deployment topology model and determining constraints of the selected element; building a preliminary data representation of a deployment activity model based on the deployment topology model while traversing the data representation of the deployment topology model, wherein said building comprises generating data that represents an element of the deployment activity model that corresponds to the selected element; evaluating constraints of the deployment topology model as the data representation of the deployment activity model is being built, wherein said evaluating comprises ascertaining one or more constraints of the selected element and determining whether the one or more constraints of the selected element are satisfied; traversing the data representation of the deployment topology model differently if one of the constraints is not satisfied according to the evaluating; automatically modifying the preliminary data representation of the deployment activity model in accordance with said traversing of the data representation of the deployment topology model differently; and committing the modified preliminary data representation of the deployment activity model built in accordance with the constraints of the deployment topology model being satisfied, wherein said building, traversing and evaluating are incremental.