The paper describes VolDmi, an open system for volume modeling and visualization defined as an interactive platform which will integrate current and future research developments, as well as specific applications. The article begins with the analysis of the main functional modules of the system. Then, the design criteria which have been followed are explained and the system's global operation is described, with special emphasis on user interaction. Subsequently, the central kernel of the system is presented. This kernel is mainly composed of input/output modules along with creation and operation modules for a generalized voxel model. Finally, the default visualization of the voxel model that has been implemented in the system and which is based on the slice stacking algorithm, is presented.