Graphical User Interfaces (GUI) are widely used for interacting with complex geosciences software such as interpretation tools or 3D model visualization programs. Despite their well designed protocol of interaction, through the mouse or the keyboard, the user is absent-minded from the main task of interpretation or visualization when applying the protocol. Furthermore collaborative work of more than two users is difficult with a standard computer configuration. As an alternate way of interacting with software, Tangible User Interfaces (TUI) are designed to simplify the actions of the user by utilizing common props (i.e. physical objects) such as rulers or pucks. Actions take place in front of a camera whose images are interpreted by software and the desired result is rendered on a desk by a projector. The user manipulates props on the projected images in front of the camera to interact with the geosciences software. Finally the collaboration of several users is made very comfortable around the desk. The GeoTUI system is developed to combine the working practice of geoscientists on desk with the use of graphical workstation. Several experiments on a workplace allowed to evaluate the advantages of TUI over GUI through the manipulation of different props.