There may be occasions where you need to swap drawings with a designer who works exclusively in AutoCAD. You may be required to exchange drawings with such a consultant several times in the life of a project. It is worth taking some simple steps in order to make this drawing exchange work well. 

The native file format used by AutoCAD is called dwg, a proprietary (closed) format and one that changes with each new release of AutoCAD. This means that it is very difficult for vendors of software other than AutoCAD to offer perfect file exchange.

Work to a standard

Before you begin the exchange process, it is a good idea to ask the other designer for a copy of their drafting standard. If you know something about the way in which layers, text styles, dimension styles etc. are used, then working with the drawing becomes much easier for both parties. Don't forget to ask what version of AutoCAD is in use.

Tip: It is just possible that the incoming drawing does not even match the sending firms own standard. As an example, the dimensions in the drawing shown below are located on layer 0 and in color red - a most unusual way to work and probably grounds for sending the drawing back for review.

dimensions

Dwg exchange - check list

1. Convert the dwg to DXF using Teigha File converter

The Open Design Alliance (ODA) provides a free tool that can be used to convert a dwg file to dxf. The DXF file format is a text file open file format pioneered by Autodesk (the publishers of AutoCAD and enables exchange of CAD information using most CAD software.

A copy of this tool can be downloaded from this site: http://www.opendesign.com/guestfiles/TeighaFileConverter

Simply install the converter, run it and convert your incoming dwg file to DXF. We suggest that you choose DXF ASCII version 2007 or (even better DXF ASCII Release 14).  

Alternatively, if you are moving a drawing file in the other direct (from gCADPlus to an AutoCAD user) export a DXF from gCADPlus and use the Teigha file converter program to make a dwg.

Tip: don't forget that AutoCAD users can import DXF so your AutoCAD designer may not require dwg format.

2. Start a brand new drawing

Set a blank template and use File>Import DXF and load the converted file.

3. Make sure via Format>Units that the settings are appropriate

The output precision should be set to one decimal place (this setting affects the dimension readings) and angle settings to 2 decimal places as shown below. It is not uncommon for AutoCAD users to set these values incorrectly. Watch also for angle settings.

Units

3. Check the quality of the incoming dwg file

Working on the imported file use the check AutoCAD drawing option on the Tools drop down menu to make sure that if required, the drawing could be saved in lcd format. If it cannot, this means that there is a problem with the incoming AutoCAD drawing. This is a proxy for testing the quality of the incoming dwg.

Check drawing

This drawing passes the test and so can be saved in both dxf and lcd file formats. 

4. Clean up the dxf file - remove any unused blocks, text styles etc.

It is a good idea to use the gCADPlus tool that reports on the 'baggage' being carried by the incoming drawing.

Check unwanted blocks

Remove text styles

Be careful about removing any generated styles. These are created by AutoCAD's MTEXT text editor and can be required in MTEXT entities.

It is likely that if the incoming drawing had a substantial amount of hatching, there will be many unnamed blocks.

dwg

5. Check file size

It is a good idea to check the file size of the newly saved drawing vs. the original. In this example, we have reduced the file size considerably.

6. Make a test transfer file

Now work on the dxf file and add a few gCADPlus ingredients and send a test file in dxf format to your designer colleague. The figure below shows the result of a test; the file is now in AutoCAD.

test

6. Hatchi​ng

In the example here, the hatch patterns applied to some areas have been exploded in the AutoCAD environment and have lost their proper hatch name. It is simple matter to create a polyline around the area of interest as shown below by selecting the 4 lines and using the Join command.

Movie Here is a small movie that shows how to deal with hatching in an incoming AutoCAD drawing.

dwg 2

Then delete the hatch and apply a named style.

Tip: a View>Regen is often needed at this point to refresh the screen.

The figure below shows that the unamed hatch style has now been replaced by hatching in the dots pattern.

dwg 5

If the drawing is opened in AutoCAD, your newly assigned hatch pattern with be there.

Hatch

Your AutoCAD colleague may (or may not) thank you for cleaning up their drawing. How much better would it be if she worked to a drafting standard which stated that all hatching will be done with named hatch patterns from the file acadiso.pat.

Blocks may ​be made very inefficiently in AutoCAD

Blocks We take a landscape CAD drawing that's come from the AutoCAD environment and show how (by making more efficient blocks, the file size can be dramatically reduced.

Work with dwg files