Converts block references, polylines, splines, ellipses, texts, dimensions and hatches into more basic entities. Dimensions are split up into lines, triangles and text entities. Text entities are split into lines, arcs and splines if appropriate. Splines are converted into polylines with tangentially connected arc segments. Ellipses are converted into polylines with arc segments. Polylines are split up into loose segments. Hatches are split up into lines. Solid fills are converted to the outline of the solid fill.