I found issues on testing Aspose CAD for .NET 18.104.22.168
The conversion output pdf files of dwg/dxf to PDF are different to source dwg/dxf.
I used your ExportToPDF sample itself, which I changed source file path only.
I attached source dwg/dxf files, correct PDF files, and output PDF files created with Aspose CAD for .NET.
I created reference PDF files for comparision with AnyDwgToPDF - http://anydwg.com/dwg2pdf/
WrongRendering.zip (1.8 MB)