Hi, Basically, a tessellated file contains mesh data (typically only geometry and some rendering information) in form of triangles or polygons. Examples of tessellated file formats are STL (used for rapid prototyping), VRML. These can be created from 3D digitizing scanners and CAD models (e.g. using Save a copy in Pro/E and selecting .STL format). Hope this information helps. Regards, Amar