Xref Attach or Overly? What is the difference?

As we continue to tear apart those Xrefs we come across Reference type. As promised in  Using Xref first step! How to attach Xref? we will look at two different reference types we have – Attachment and Overly.
Attach external.JPG

Attached external reference

Attached will mean that referenced drawing (for example “A.dwg”) will be part of current drawing (for example “B.dwg”). That way if we use our new drawing (drawing “B.dwg”) as reference in drawing “C.dwg” we will see both drawing “A.dwg” and “B.dwg”

Note: We can use as many nested drawings as we want, if they are all attached, all be shown in the current drawing.

Overlaid external reference

Overlaid reference will be used when we need to use other drawing but we don’t want to have nested references. If we have drawing “A.dwg” and Overlay it in drawing “B.dwg” and reference drawing “B.dwg” to drawing “C.dwg” we will only see objects from drawing “B.dwg”

Note: No matter how many nested drawings we have, as long as they are Overlaid we will see only the previous one (only one level back)

Here one real life example:

Attachment: We have our Main floor.dwg attached to our furniture.dwg. We also have our Main floor.dwg attached to our Water and sewer.dwg. Now we want to reference those two drawings in our Ventilation.dwg. 

What happens now is that we have our Main floor.dwg nested two times in our new drawing and if we continue to use attachment we will have quite a mess.

Overlay: We have our Main floor.dwg overlaid to our furniture.dwg. We also have our Main floor.dwg overlaid to our Water and sewer.dwg. Now we reference those two drawing in our Ventilation.dwg and here is the result:

We don’t see our Main floor.dwg in Ventilation.dwg as we did in Attachment example. Now if we want our Main floor we will just reference it into ventilation.dwg

Don’t worry if you have done something wrong you can correct your mistake later from external reference menu ( “XR” command)

Using Xref first step! How to attach Xref?

In the previous post about Xrefs we talked about the definition of external references and what are they used for. Here we will learn how to properly attach an Xref and what are the different options.

How to attach Xref?

Before we attach drawing we need to have it, so in this example we will use a drawing of walls, doors and windows of a house for our base.

Now, for example, we will make a new drawing called Furniture in which we will put some of the furniture of the house. There are two ways to attach DWG file:

  1. We go to Insert ribbon then click on Attach.
    A window will pop up here we find the drawing we want to attach and click Open.
    Note: Don’t forget to select File type at the bottom!
  2. The second method is preferred by me. Here we will type in command line “XR” and hit enter. Now a window will pop up, here we can see all the attached external references and we can work with them. Since we have no references attached we go to the upper left corner and click on the small arrow there we can see Attach DWG..  and click on it. New window will pop up here we select our drawing and hit Open.
    Note: As you can see we can attach not only DWG files but Images, DWF, DGN etc.

After clicking on Open an Attach External Reference window will pop up. Here we will go through all the options step by step

  1. Preview – Here we can see a preview of the drawing that is going to be attached
  2. Browse..- If we have missclicked we can go and browse for another drawing
  3. Reference type – We have two options Attachment and Overly you can find details in Xref Attach or Overly? What is the difference? , but long story short if we use Overly we don’t see nested drawings if we use Attachment we see all nested drawings.
  4. Show details – Nothing interesting here only the file path
  5. Scale – Here we can scale our reference drawing by X, Y, and Z or we can choose Specify On-Screen and specify the scale dynamically.  For our example, we won’t touch anything because we want the drawing to be the same size as the original.
  6. Insertion point – We can choose a specific insertion point by X, Y and Z or we can choose one On-screen. We will again leave it as it is.
  7. Path type – Here we have 3 options – No path, Full Path and Relative path. In post Xref – choosing our Path Type you can have a detailed explanation of all Path Types.
  8. Rotation – We are asked to choose rotation for our reference if we want one, we can also rotate it On-screen. For the example we will leave it to 0.
  9. Block unit – This shows us the scale factor of our xref. Since both of the drawings are set to feet scale factor is 1.

Now we click OK and we will have our main floor drawing attached to furniture dwg.
Don’t worry if you messed up with some of the options you can always correct them in the drawing!
We will have to type “zoom” command (or just “Z“) and then “Extents” to see our x ref attached and we can start adding some furniture.

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