The Unified Modeling Language (UML) supports a wide range of diagrams for modeling software development concerns. UML diagrams are independent but connected; their meta-model describes them under a common roof. Despite the advances of UML, we found that the problem of ensuring consistency between UML diagrams has not been solved. In the past years, we have developed an approach for automated consistency checking, called VIEWINTEGRA. Our approach provides excellent support for active (preventive) and passive (detective) consistency checking. We make use of consistent transformation to translate diagrams into interpretations and we use consistency comparison to compare those interpretations to other diagrams. Our approach was applied to a number of applications where we found the separation of transformation and comparison to be highly beneficial in addressing consistency-checking scalability & usability issues. This paper introduces our UML-based transformation framework, discusses how it aids comparison, and demonstrates how it improves consistency checking.