Many of us use Tekla BIMsight or Solibri for IFC viewing, but there is another free option: FZK Viewer. It is just a 10mb download, unzip and go.

It has a Walk tool like Navisworks for easy navigation, and it can even export to a number of formats, including:
DXF (cool! quick IFC to DXF conversion anyone?)
VRML 2
STEP
Collada
Google Earth
CityGML

Additionally, it can open gbXML and GML files. All in all, a handy piece of software to have if you are dealing with IFCs on a daily basis.

Oh, did I mention it can Merge .xyz point cloud files to the scene?

Build 771 direct link:
http://iai-typo3.iai.fzk.de/www-extern-kit/fileadmin/download/download-vrsys/FZKViewer/FZKViewer-4.2-Build-771.zip
On opening an IFC, it produces a log file that can quickly locate geometry problems:

Download page:
http://iai-typo3.iai.fzk.de/www-extern/index.php?id=2315&L=1

Main page:
FZKViewer

We often have to deal with data that hasn’t always “lived” in our CAD, BIM or Revit world. Take a hand sketch, for example – how can you get that into a format that can easily be used in AutoCAD or Revit? Some PDFs have vector information, which I have described how to access before. But the below workflow takes it one step further – how to get any raster image into a vector format, using a few free tools.

Here’s how to do it, without Adobe Illustrator:

  1. Make your source file (PDF / Scan etc) into bitonal TIFF image (I use Bluebeam and Irfanview in the video, but you could easily save the PDF to image using GSView)
  2. Open in Inkscape
  3. Vectorize using Path – Trace Bitmap… Brightness steps, set to 2.
    Untick: Smooth, Stack scans, Smooth corners and Optimize paths.
    (this step makes the black and white image into lines and outlines)
  4. Save as EPS
  5. Open in GSView (requires Ghostscript and pstoedit)
  6. Save as DXF (using Convert to Vector format). From here, you can get to AutoCAD or Navisworks easily…
  7. Open in AutoCAD
  8. NWCOUT and/or
  9. Append the DXF directly to Navisworks
  10. Scale and position appropriately

Here’s a quick video of the process:

The file sizes at each step look like this:

In Google Docs, you probably know that you can upload files and view them with the Google Docs Viewer.

But did you know that Google Docs Viewer can display the following formats?

  • Apple Pages (.PAGES)
  • Adobe Illustrator (.AI)
  • Adobe Photoshop (.PSD)
  • Autodesk AutoCad (.DXF)
  • Scalable Vector Graphics (.SVG)
  • PostScript (.EPS, .PS)

If you want to view something online, just put the URL of the file in at the following link:
Google Docs – Viewer

For a more complete list of filetypes, check out this link.

Sometimes you will have access to a PDF file, but not to the original DWG.  Is there any way you can get the base vector data, such as lines and arcs, out of the PDF and back into a DWG?  Yes, there is – and it’s free.

You will need 3 things:
Ghostscript or here
GSView
pstoedit (or Windows exe link here)

Download and install each of the above tools.  Make your life easy and stick with the 32-bit version of everything.

Once you have installed them all, open a PDF file using GSView.  GSView is usually located in  
C:Program Filesghostgumgsviewgsview32.exe

With your PDF open, take the following steps:

  1. Click on ‘Media’ and set the correct paper size.
  2. Go to ‘Edit’ and click on ‘Convert to vector format…’
  3. At the resulting PS to Edit dialog box, choose dxf_s, and add the following Driver options:
    -mm -splineaspolyline -splineprecision 10
    (I have found these settings to work quite well)
  4. Click OK.
  5. Select the page in the next dialog (usually only 1), press OK, and then pick a place to save the DXF file.
  6. Click Save.
  7. Open in AutoCAD and scale to correct size.
  8. Save as DWG.

If you have any problems, feel free to comment and I will try and help you out.  If you intend to import the DWG into Revit, keep in mind that Revit is not very impressed with very short lines.

Enjoy your PDF hacking!

Let’s say you have AutoCAD file of unknown origin, and it has some wacky or imprecise units (like the distance between two walls is 8250.092234897). What you need to do is reduce the precision, such that all the decimal points get ‘chopped off’.

To do this:

  • Open the offending DWG in AutoCAD.
  • ‘Save As’ and choose a DXF format.
  • Go to Tools menu – Options (see below)

  • Choose DXF Options, ASCII Format and set the ‘Decimal Places of Accuracy’ to the desired value (choosing 0 will remove all decimal places):

  • Hit Save.

I recommend that you now open the DXF file you saved, and then resave it as a DWG file.Now you can insert your file into Revit, and you won’t have to deal with imprecise units.Please note that this process may result in some ’rounding off’ of values – you may want to double check the resulting file.

I found this process at the following link:
Forum Link