Distributed simulation cloning technology is designed to analyze alternative scenarios of a distributed simulation concurrently within the same execution session. The goal is to optimize the execution time for evaluating different scenarios by avoiding repeated computation. In terms of High Level Architecture (HLA) based simulations, a federate may make clones to explore different scenarios at decision points. It is desirable to use an incremental cloning mechanism to replicate only those federates whose states will be affected. This paper discusses the theory and issues involved in incremental distributed simulation cloning, which employs an event checking algorithm to ensure accurate sharing and initiates cloning only when absolutely necessary. Experiments have been performed to compare the performance of entire cloning and incremental cloning mechanisms. The experimental results indicate that cloning technologies can effectively reduce the time of executing multiple scenarios, and ...