Phase transformations involving growth and impingement of randomly centered and oriented rods, fixed in number and cross section, have been studied using computer modeling techniques. As expected, the Avrami equation does not adequately describe the process. Deviations of up to 15% from the Avrami predictions are frequently encountered. The biggest deviations are in the Avrami constantK, which contains the rate constants, rather than in the time exponentn, which reflects growth and nucleation modes.