As engineering systems become more complex new tools and mechanisms are needed that enable engineers to effectively manage complexity in system design and analysis. To fully understand a complex system, an engineer often needs to utilize multiple analysis tools. Today these tools are often uncoupled and their impact on the overall performance of the system is unknown. Effectively implementing multiple disparate models in design and analysis requires integration of models in an environment which supports decision making through human interaction. As a first step this requires developing a framework that can support a comprehensive decision making environment in which an analyst can develop a complete engineering system. In this thesis a portion of this framework was developed that links together intuitive user interfaces, high fidelity models, and Microsoft Office tools. This enables decision makers to utilize well developed and familiar analysis tools integrated with more complex and specialized tools to facilitate complete system simulation. This development is implemented through the software framework of VE-Suite, an open-source library of tools being developed at Iowa State University that enables virtual engineering processes. The development and implementation is demonstrated with two engineering examples. These are 1) the analysis of fire hazards within an auxiliaries room in a nuclear power plant and 2) interactive design of heat transfer systems within biomass cook stoves. In both examples the analysis requires integration of computational tools, geometrical models, and user control interfaces to create an environment which supports an engineer's ability to supplement the analysis with human experience and intuition. In analyzing fire hazards the engineer needs to be able to walk through a virtual representation of the space in question, place and build a fire, and interactively work with results displaying the impact of fire. In interactive cook stove design, the analyst needs an intuitive mechanism for making design changes, the ability to perform high fidelity analysis on the fly, and an effective means for understanding the computational results. In both cases several disparate models are linked together using the tools developed as a part of this masters thesis to create a comprehensive decision making environment.