How to Convert a 73Mb DWG?
Using PDF3D ReportGen that can be converted, with some care and adjustment. By simply taking default settings, the 73Mb DWG is converted to a 23Mb PDF containing 10 million triangles. This is often unstable or unusable in the Adobe reader because of the model size. A number of adjustments can be made for the conversion to create a more practical PDF.
The DWG loader can be adjusted to convert only 2 levels of hierarchy without layers. See Interface Settings, Teigha Interface parameters. On these parameters the tesselation tolerance can be increased. Lines can be suppressed for a much smaller file.
The Advanced tab VCT should be disabled, and by enabling the simplification options to reduce the triangle count to perhaps to 1 million or 500k. At 800k triangles without lines, the PDF generated is 3 Mb, far smaller than the 73Mb DWG.