In the research performed in the project "Conversion Topographic Data Base objects to three-dimension for dynamic geo-visualization" (N N526 192537) is developed a concept of 3D Topographic Data Base (TBD3D). TBD3D is intended to be an additional module of existing 2D civil Topographic Data Base (TBD) that allows three-dimensional visualization of topographic data. Conception of three-dimensional multiresolution topographic database (TBD3D) assume that all features in TBD3D exist in three dimensions on three different Levels of Detail (LOD). Features in TBD3D will be presented in two forms: as real generalized features (e.g. buildings) or by 3D symbols. Information about three dimension of real features will be gain from Land and Buildings Cadastre (number of storeys), stereodigitizing, LIDAR data or from superposition of 2D data with digital terrain model (e.g. roads, trains, watercourses, landuse). One of the stages of this research was to develop a GML application schema for TBD3D (TBD3DGML) to transfer data between different geo-information systems and share them over the Internet. The structure of files and directories of this schema is based on the existing schema for 2D topographic data TBDGML. While the geometry and definition of TBD3D objects has been adapted to the requirements and standards of the third dimension and GML3. In addition, in TBD3DGML schema it is possible (as in CityGML) to describe the prototype objects (ImplicitGeometry) and define the appearance of the surface by means of Appearance or TexturedSurface schemas. Developed application schema TBD3DGML was tested at selected TBD3D objects representing all geometry types used in the schema. FME Safe Software was used to write data in the TBD3DGML schema. Then generated data were validated for compliance with the developed schema and loaded into the GML browser AristotelesViewer v.1.3.