A flexible and extensible object-oriented 3D architecture: application in the development of virtual anatomy lessons.

"Anatomic VisualizeR" represents the first application to be developed using a 3D architectural framework created at the University of California, San Diego, School of Medicine. This application combines 3D anatomic models (based on the Visible Human dataset) with supporting 2D media (e.g., diagnostic imagery, surgical videos, etc.) to establish a comprehensive learning environment for anatomy. "Guided lessons" are being created to address complex curricular and learning objectives. Faculty expertise is represented in these preconfigured lessons, in part through the specification of appropriate content and the incorporation of activities to enhance visualization. These lessons are an intellectual framework which ensures that clinically-relevant issues and ancillary learning opportunities are available. The curricular exercises are non-sequential and can be interrupted at any time; users are encouraged to freely explore the environment. At the core of Anatomic VisualizeR's object-oriented architecture is the ability to identify, access, view, and manipulate heterogeneous content. The capacity to query a database gateway to retrieve specified resources has been built into the application. Encapsulation of individual elements to form 3D display objects ("blocks") enables Anatomic VisualizeR to efficiently manage 3D models, 2D images, text, sound, and video. The "block" paradigm also allows Anatomic VisualizeR to associate contextually appropriate display characteristics and behaviors with the various content elements. For example, the anatomic model block provides the capability to "link" and "unlink" the anatomic models and to alter their transparencies. The anatomic models can be displayed concurrently with other blocks to facilitate structural comparisons. Anatomic VisualizeR marks a major milestone in our developmental efforts. While lessons and database content are still not complete, we are confident that it will become the first tangible realization of our vision.