Importing PDF into CAD Drawings
By John TeSelle, LineType Software Inc., August 25, 2003
There are several ways to import a PDF into a CAD document. Each has its advantages and disadvantages, and none is perfect.
Cut and Paste Method
This is the simplest and most direct method. It copies a bitmap image only.
- In either Acrobat or Reader, choose the "Snapshot" or "Graphic Select" tool (looks like a rectangle with some shapes inside it)
- Select the area of the PDF to be imported. A dashed line will be drawn on screen to indicate the area.
- In version 6.0 of Acrobat/Reader the image will automatically be copied to the clipboard; in version 5.0, you must choose Copy after the area has been selected.
- In the CAD application, choose Paste to paste the image into the drawing.
Note that this technique only copies a bitmap image at the current screen resolution in Acrobat or Reader. The appearance of the image is also affected by the smoothing settings that are in effect at the time. Choosing Smooth Line Art in the Preferences dialog box will result in a better-looking bitmap export.
In order to produce a higher-resolution bitmap image, try this:
- Zoom out until the entire area to be copied is visible
- Select the area to copy using the "Snapshot" or "Graphic Select" tool as indicated above
- Without clicking anywhere on the screen, choose a higher zoom factor from the zoom menu - usually 400% or 800% will be sufficient.
- Now choose Copy to copy the higher resolution image to the clipboard.
- If too high a factor is chosen, an error message may be displayed indicating that there is not sufficient memory on the clipboard for the bitmap image. In this case, reduce the screen zoom factor and try the copy again.
Note that this method copies the image as a 24-bit RGB image. If only black-and-white output is needed, the image can be pasted into an image editing program and converted to grayscale (and downsampled or compressed) before importing into the CAD application. This can help to minimize file sizes.
PDF Conversion Method
It is possible to convert vector graphics in a PDF file into a DWG or DXF file. However, the resulting drawing may be difficult to use. Lineweights will be lost or converted to thin rectangles, text will lose its association as text, and all objects will be on one layer.
To try this method, a conversion utility will be needed. Two options to consider:
- One shareware utility that uses the public-domain Ghostscript interpreter is called "GSView" - it must be installed along with Ghostscript with an additional utility called "pstoedit." Click here for more information.
- The LeadTools ePrint driver ($99) can convert PDF and other file formats to DXF and many other vector formats. Output is not perfect (text is rasterized) but overall linework is transferred. Click here for more information.
This method works around the difficult of importing PDF files into CAD drawings by creating a PDF of the CAD drawing, and then importing the other PDF into that... For more information, see the article "Using PDF to Import Text into Drawings" - the same technique can be used for image-based PDFs.
About the Author
John TeSelle is an architect in private practice in Nashville, Tennessee, and is the founder of LineType Software Inc., a development company providing tools and information to enhance the use of PDF documents in architecture and engineering.
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