Many activities in computer graphics can be regarded as experiments on virtual objects or models. In the process of experimentation the existing models are gradually improved and new model categories emerge. The Virtual Laboratory (vlab) is a software environment designed to support model development by facilitating the manipulation of models and providing mechanisms for storing and retrieving large numbers (e.g., thousands) of them. The models can be shared between users who work at different geographical locations over the Internet. In the paper we first clarify the essential concept of the Virtual Laboratory by describing its operation from a user's perspective. The modeling of plants serves as a sample application. We then present the key elements of vlab design and implementation, discuss the obtained results, and present their possible ramifications in the context of related ideas. Reference P. Federl and P. Prusinkiewicz: Virtual Laboratory: an Interactive Software Environ...