In this paper we introduce a function-defined extension of Virtual Reality Modeling Language where analytical formulas are used for defining geometry and appearance of 3D shapes. By "functions" we understand analytical definitions with parametric, implicit and FRep formulas. In our model, these very different analytical representations can be used concurrently for defining geometry and appearance of the shapes. The proposed structure of the software allows for its extending with any proprietary function-based models. The extension is designed for collaborative shape modeling as well as for building shared virtual worlds. This is illustrated with the implementation of the collaborative shape modeling hands-on experience which is a part of the Virtual Campus-a shared cyberworld of Nanyang Technological University.