How do I convert the diagrams provided by a public tender from pdf into dwg without losing the grey lines?

Question

The Client provided pdf file for the existing diagrams of a Building Services Engineering public tender project I am handling. Asking for the dwg file from the client is not available because I am technically just an intern who took the public tender as the base of my final year project, in which I have to design my own system above the existing one.

I have attempted to just convert the pdf into dwg on AutoCAD. The issue is that since the tender diagram utilizes different colour to differentiate the floor plan from the system design(floor plan uses the colour grey, and the system design is proper black), AutoCAD files to identify the grey colour. As a result, the dwg product lacks the floor plan, only the system design remains.

I have attempted to convert the pdf file into png, and then use Photoshop to manually change the line colour of the diagram. But whenever the pdf file is converted into png, the resolution is so low that the details become unintelligible.

Can anyone advise me how to resolve this issue?

Answer 1

Assuming that your use of the data is legal, you should keep the data in vector format and not convert to a bitmap format.

Inkscape can import PDF and export to DXF. Once you have the file open you can check for layers which, if set up properly, may help to strip out much clutter with little effort. Otherwise you'll be using commands such as Ungroup or Break Apart before selecting stuff for deletion.