This paper adresses the forthcoming technical issue of collaborative geometric modeling, using a previously existing virtual sculpting framework. A software architecture is described, called SpinCAS (Spin3D Computer Aided Sculpting) providing the user with the ability to both sculpt objects virtually, and share such modeling along the internet in realtime. Technical issues are discussed, especially regarding classical geometric tools applications on network based applications. The notion of spacial lock is also closely studied, from a human-computer interface point of view, and also from a technical point of view.