A method of calculating electrical interactions of circuit elements in an integrated circuit layout without flattening the entire database that describes the layout. In one embodiment, a hierarchical database is analyzed and resistance and capacitance calculations made for a repeating pattern of elements are re-used at each instance of the repeated pattern and adjusted for local conditions. In another embodiment, a circuit layout is converted into a number of tiles, wherein the resistance and capacitance calculations made for the circuit elements in the center and a boundary region of the tiles are computed separately and combined. Environmental information that affects electrical interaction between circuit elements in different levels of hierarchy is calculated at a lower level of hierarchy so that such calculations do not need to be made for each placement of a repeated cell and so that not all interacting elements need to be promoted to the same hierarchy level to compute the electrical interactions.