In the Drift Control Module, the "Virtual" Load cases created and analyzed in RAM Frame are "paired" with a corresponding "real" load cases. The "pairing" of loads is an important feature of energy methods and care should be taken in identifying what virtual and real load cases to pair. For example, for studying Drift Control in the global X-direction, a virtual load case applied in the X-direction should be paired with a real load case in the same direction. These load pairs could be "single" load pairs or "multiple" load-pairs. While single pairing is what is commonly used, multiple pairing may be necessary to study drifts in a none-orthogonal direction. The load pairs are defined using the Loads - Load Pairs command in the Drift Control Module, which lists both the analyzed virtual and real load cases. Pairing is done by specifying the virtual and real components of the pair and the factor that multiplies them. The factor is usually taken as 1.0.

Once load pairs are defined, the user needs to select the " Process-Analyze " command to perform the Drift Control analysis. The module then evaluates the participation factors (PF) of each member and color-codes the elements according to their contribution to the flexibility of the building.

For example, if the user is interested in reducing the roof story drift due to an earthquake load, an earthquake load case is selected as the "real-load" component of a load pair. The "virtual" component of the load pair will then be a virtual load that has lateral forces only at the roof level even though the real displacement is caused by a distributed earthquake load. The structure is then displayed with the PF that elements are experiencing from the stresses induced by the earthquake load case.