Explanation of an XREF

[mnhollinger]

Can someone explain what exactly an XREF is? According to my online class notes it is described as being the following.

Note: An external reference can be a drawing file, image, PDF, or one of several other file types. An XREF is an external reference that's specifically a DWG file.

My online class notes emphasize the independent nature of an XREF. You can modify the XREF without affecting the drawing. Also, don't use your drawing's layer names for an XREF drawing. Doesn't that get confusing? Is there a complete list of XREF file types?

One more thing. For something like a coordinate list, I used to use an MS Word document inserted into a drawing. It was something called OLE (Object Linking and Embedding). Do they still use that? Is it better to XREF a PDF for that kind of thing?

[nkiakas · Accepted solution]

Hi @mnhollinger 

Usually the Xrefs are other DWG files, in the back ground helping the user with the design procedures.

Why do we use xrefs? During the design procedure, we may need to superimpose several drawings for the same area. Drawings from the past, old design, existing condition (topo survey) or other drawings for the future (for example another revision for our design).

Now lets focus in the above. Think that you have to add all the above, and then when you finish your design, of course you don't need them, have to delete. So while working your file will become huge size and of course with the possibility to delete something usefull.

Xref don't increase the file size. You can easily switch on/off. They have their own layer list, when you edit them automatically get updated when they are inserted in your file. They are printable and so many benefits.

You said you tried to insert a list of coordinates from MS word to AutoCAD as a reference. I assume that you wanted to create point objects in AutoCAD, where the coordinates are in MS word file. You can't import points to autocad by xrefering a MS word file. There are other tools to do it, and better to do it in Civil 3d.

Regards

[rdavisMX6RG]

Also, when a revision is made to say a site plan, if you dont use an xref, you have to find the part with the change and update.  On a big job this gets VERY messy.  Architect makes change, you update your xref and now with one command, everyone has the latest details.

PS: Handy tip.  If you need to send you latest dwg, including xrefs, to another consultant, use eTransmit command.  It takes everything in the dwg, xrefs, plot styles, referenced background images etc and attaches so as the receiver just extracts the .zip file and off they go...

[mnhollinger]

You said you tried to insert a list of coordinates from MS word to AutoCAD as a reference. I assume that you wanted to create point objects in AutoCAD, where the coordinates are in MS word file. You can't import points to autocad by xrefering a MS word file. There are other tools to do it, and better to do it in Civil 3d.

I apologize for adding something off-topic to my post. The coordinate list was just a list of points to be read by someone reading the drawing once it had been printed. Another example would be if it had been a mechanical drawing with a parts list. I also wanted to know if using an MS Word file, or better yet an MS Excel file, inserted into a drawing using OLE (Object Linking and Embedding) would be inferior/superior to using an XREF of a PDF file.

[mnhollinger]

Architect makes change, you update your xref and now with one command, everyone has the latest details.

That's excellent. Thanks.

 If you need to send you latest dwg, including xrefs, to another consultant, use eTransmit command. 

That's an excellent tip. Thanks.

[neaton]

We have sepatate drawings for different parts of the project: surveyed existing features, proposed roadway (curb, gutter, sidewalk, etc), proposed roadway striping and symbols,  illumination, signalization, etc. These dwgs are added to our plan sheets as xrefs. Sometimes we need all of them,  sometimes only one.  Our titleblock is also added to the plan sheets as an xref.

Using separate drawings allows multiple people to work on the project at one time.

[mnhollinger]

Using separate drawings allows multiple people to work on the project at one time.

That would be a time saver in my office. One person could work on the boundary, and another could work on the legal description.