This paper presents our tool set implementation for scenario-based multithreading of object-oriented realtime models and an accompanying experimental validation. Our tools enable the automated, schedulability-aware implementation of real-time objectoriented models, exploiting an existing CASE tool. Our implementation is facilitated by (1) our customized runtime system modified to support scenario-based thread execution, (2) a design model template that centralizes the arrival of external inputs, (3) a model analyzer tool, and (4) a model-specific code modifier tool. Our tools simplify design by removing thread-related design concerns from the modeling process, separating design and implementation. We performed validation by conducting experiments that clearly demonstrate the performance improvements that can be gained through our scenariobased implementation: response time improvements for high priority tasks of as much as 70% and a 5-fold decrease in blocking or the elimination of bl...