What is a x-ref?

-Alvin

Alvin, You can insert any drawing file as an external reference or xref in the current drawing.

When you attach a drawing file as an xref, you link that referenced drawing to the current drawing. Any changes to the referenced drawing are displayed in the current drawing when it is opened or reloaded.

A drawing file can be attached as an xref to multiple drawings at the same time. Conversely, multiple drawings can be attached as referenced drawings to a single drawing.


Also, from TC manual:

An external reference (xref) is a kind of a block in that it is
stored in the current drawing’s block library. However,
unlike a block, the objects associated with an xref definition
are not stored in the current drawing; they are stored in
another drawing file. When you create an xref, the entire
contents of this other file are imported as a block. See
"Blocks" on page 269.
Xrefs are usually used to display the geometry of a common
base drawing in the current drawing, such as a frame. They
can be taken from files any formats readable by TurboCAD
(see "Other CAD Formats" on page 3).
Only files that have objects in Model Space can be added as
Xref’s.
1. To import another drawing as a block (xref), select
Format / Create External Reference.
2. In the External Reference File Location window,
select a file type and locate the desired file.
3. If you want the path to the referenced drawing to be
relative to the current drawing (as opposed to an
absolute path), check Return Path as Relative.
4. The selected file is added to the block library of the
current file. You can view it and insert it using the
Blocks Palette. However, you cannot edit an xref in the
Blocks Palette - you must change the original file.

This might help: External References.

Thanks Steve and John,

After reading your posts it sounds to me that an "x-ref" (which is shorthand for External Refernce, I have surmised) is a lot like a "Symbol".  What is the difference?  (I'm on TC ver.11)

Thanks, Alvin

re: I have surmised this is a lot like a "Symbol".  What is the difference?  (I'm on TC ver.11)

Similar, but it's actually a Block. Each time I insert a Symbol into TurboCAD, I get all its geometry (2D objects and/or 3D objects) and the file size increases depending on the symbol. Each time I insert a Block or XRef, I just get a reference to the stored geometry in the Blocks palette or the external drawing file and file size increase is negligible.

Allright, Thank you, John-

I'll have to experiment with the three options some.  Over the years, I have only used Blocks- not knowing about x-ref's (External References) and not finding good use for Symbols.  When I do use a Symbol, I generally convert it to a Block, if I am going to use it repeatedly.

Makes me wonder when it is best to use a Symbol versus an External Reference (x-ref) versus a Block.

-Alvin

re: When I do use a Symbol, I generally convert it to a Block, if I am going to use it repeatedly. Makes me wonder when it is best to use a Symbol versus an External Reference (x-ref) versus a Block.

I think you're using them properly. The way I look at XRef's, they're basically a sub-assembly to a larger assembly. You could bring that sub-assembly in as a Symbol (or just copy-n-paste), then make it a Block, but you bog down your master drawing with unneeded info. A reference to the external sub-assembly drawing will do a better job. XRef's are a bit more friendly in V17 as opposed to V11. You get more control through the Blocks palette and Layer control in the Design Director.

re: When I do use a Symbol, I generally convert it to a Block, if I am going to use it repeatedly. Makes me wonder when it is best to use a Symbol versus an External Reference (x-ref) versus a Block.

I think you're using them properly. The way I look at XRef's, they're basically a sub-assembly to a larger assembly. You could bring that sub-assembly in as a Symbol (or just copy-n-paste), then make it a Block, but you bog down your master drawing with unneeded info. A reference to the external sub-assembly drawing will do a better job. XRef's are a bit more friendly in V17 as opposed to V11. You get more control through the Blocks palette and Layer control in the Design Director.

Than you John for the reply-

So when, in your opinion, is it advantageous to use a Symbol?

-Alvin

re: So, in your opinion, when is it advantageous to use a Symbol?

Why does this sound like a loaded question?! 

When I don't want to create the part from scratch, and when I don't want to have a Template loaded with extraneous Blocks that I may not use.