Shared Simple Virtual Environment (SSVE) is an object-oriented software framework designed for object-focused small group collaboration in highly dynamic virtual environments. Compared to most other collaborative virtual environment systems, SSVE allows a team of six to eight people to collaborate closely on a highly interactive model construction task. SSVE is a "multi-multi" framework— multi-user, multi-threaded, multi-platform, and multi-modal. Numerous interaction, awareness and collaboration mechanisms are provided by the ramework and by applications that use the framework, including "what you see is what I see," deictic references, and exclusive object access. Several concurrency control mechanisms are also supported through the framework, including those suitable for closely-coupled synchronous collaboration in highly dynamic virtual worlds. In addition, support is provided for emergent group collaboration modes, and a novel user interface widget, the collaboration tree, is introduced to facilitate subgroup formation and integration of task results. In short, SSVE is a framework for the development of applications which explore group collaboration mechanisms in highly-interactive shared virtual environments. A small pilot study that used the framework to validate the utility and stability of the framework, as well as to investigate larger issues of group collaboration, is also presented.