Topic: XREFs

[hudster]

I'm writing our CAD manual and have reached the part on xrefs. I'm thinking about changing to overlayed xrefs as I prefer them as it removes the possibility of nested xrefs.

Whats your preference and why?

[jonesy]

Most of our xrefs are overlayed to stop circular referencing/nesting etc.

Saying that, there are also a couple of older jobs that use the attach method.

[Greg B]

Can you elaborate on the differences between Attached, Overlay, and what the third one was?

I know I use DataCAD, but we do have xref's and I want to see which is relevent.

[ronjonp]

Can you elaborate on the differences between Attached, Overlay, and what the third one was?

I know I use DataCAD, but we do have xref's and I want to see which is relevent.

Check out this thread:

http://www.theswamp.org/forum/index.php?topic=6156.msg75044#msg75044

[glee]

We use overlays too.
Keeps our sheets simpler without possibility of something not meant to be there popping up in the sheet when no one is paying attention. 

[deegeecees]

A general conclusion I've found to be true:

Attach - Used for Assembles/Sub-assemblies
Overlay - Used for reference information

This may be the mechanical drafter coming out but it is a generalization which will hold water with any discipline that uses different semantics.

[Greg B]

So the main difference is whether it allows nesting or not.

Hmm...DataCAD's xref manager has a toggle to allow nesting or not.  This toggle also shows up when you shift right-click on an xref.

So to be honest I'd have to go with attached.

As for block...why when you'd want it updated with changes?

[Greg B]

I was thinking that if you wanted something attached, wouldn't that be more in the line of binding?  Or am I off my mark?

[Chuck Gabriel]

You are off the mark.

Attach:  A is xrefed into B.  B is xrefed into C.  A is brought along for the ride into C.

Overlay:  A is xrefed into B.  B is xrefed into C.  A is not visible in C.

Bind:  External link is broken and the xref becomes a block reference.

[pmvliet]

we use overlay majority of the time.
When you attach, your layer dialog box can become huge depending on how many other reference files are brought in.

Small jobs you could use attach, and attach could save you some time depending on how you set up your files.
example: if in your sheet file A-101, you have the arch base, mech base, structural base, electrical base referenced in.
But your arch base also have those same files referenced in. so if you used attached, you wouldn't have to reference the
same files in again...

Pieter

[Greg B]

You are off the mark.

Attach:  A is xrefed into B.  B is xrefed into C.  A is brought along for the ride into C.

Overlay:  A is xrefed into B.  B is xrefed into C.  A is not visible in C.

Bind:  External link is broken and the xref becomes a block reference.

Thanks Chuck...

Pieter

DataCAD does not include the layers of the xref within the layer manager of that current drawing.  To change the layers in the xref we have to use the Xref manager.

[CADaver]

overlay only
with a couple of hundred designers working with several thousand files you trip over yourself using attach.

[pmvliet]

DataCAD does not include the layers of the xref within the layer manager of that current drawing.  To change the layers in the xref we have to use the Xref manager.

Much like how Microstation J was/is.

[CottageCGirl]

We have only used attach to date, but that is probably due to the wide range of skill levels in my dept.  I actually have never tried overlay, but from what was said about A xref into B -B xref into C then A is not visible---I'm not sure we would want that, since I still have people confused when something gets locked........Overlay seems like it would be better for complicated-multi/purpose drawings......

[hudster]

Yeah, but wait till you have to bind an xref and it's nested in a drawing, which has a nested xref, which has a nested xref, which has a nested xref etc etc.

I've seen that and it wasn't pretty

[dtkell]

Always overlay.
If there is a drawing that I don't need any of the information from, it gets left out.

[whdjr]

I would have to say both although the more I use Overlay the more I see an importance for it.  It is also a great tool when you have many project members.

[t-bear]

eah, but wait till you have to bind an xref and it's nested in a drawing, which has a nested xref, which has a nested xref, which has a nested xref etc etc.

I've seen that and it wasn't pretty

When you bind the parent xref, all the others come along for the ride...simple!  There are two options for the bind command....bind and insert.  Binding keeps all layers  from each child xref separated...you have a "part-01" on two xrefs.."A" and "B".  The layers would be "A/$part-01$" and  "B/$part-01$".  With the bind option, both would be on "A/part-01" layer.  A little tricky at first, but easy to get the hang of it.

 We use attach exclusivly...all our stuff is assemblies and sub-assemblies.  When I do a site layout, it includes the gas handling system, flare and the interconnect piping.  In the GHS I have a control cabinet, blowers, piping, the skid and instrumentation, all of which are xrefs in the GHS, and all of which must show on the overall site plan.  With overlay most all of this would not show. 

Basically, it all boils down to how/what you are drafting.  An archi would find overlay very handy in creating the various prints for each dicipline...electrical doesn't need plumbing who doesn't need.......  For us however, attach is the only way to go.

[Chuck Gabriel]

For what it's worth, I use them both depending on what I want to accomplish.

[Royalchill]

 :pissed:

[Bryco]

Do most people refedit the xref in place or open the xref drawing? (I've only just found out about xopen, nice command)

[MP]

We consider refedit evil and disable it.

:pissed:

[Bryco]

That could also be an arguement for overlays I suppose. As if something is colliding with your piece, to relocate your piece in its original dwg you need to bring in the xref  that shows the collision.

[glee]

I prefer xopen instead of refedit.  Does what refedit used to be in R14. 

[CADaver]

REFEDIT for xrefs is of the devil. It's use here will draw the ire of the CAD manager :pissed: :realmad: and he's an ugly mean bast.... ummmm...  wait a minute.... nevermind.

REFEDIT is a most wonderful tool for redefining blocks, but it's use for XREFS is disallowed.

Back to the original question, I wish to modify my fist answer.  We use both depending on what we need.  Sometimes the file is ATTACHED if it is a component within an assembly that must follow the assembly whereever it goes, especially if the component is used several times within the assembly.  We are slowly moving away from that scenario, and using REFEDIT on BLOCKs within the drawing instead.

[Jim Yadon]

I prefer to keep my options open and use either depending on the situation. If I really thought about it, I could make a really good argument for nested XREFing. It makes perfect sense in my head but doesn't sound right when I read it.

[glee]

I'll revise my initial response about x-refs. 
For any file that's going to be in my sheets, I use overlays and try to avoid nested x-refs.
However during the course of working on drawings there maybe reasons why I will switch an x-ref back to an attachment.
I.e. while working on building sections or elevations. Plans would be x-refed in as overlays to serve as a guide.  But supposing I needed to show the proper grades, instead of x-reffing the civil drawings in, I'll just drop into the plans and temporarily switch the civil site base back to attach, reload the plan in the elevations and now I can pull lines down from the topo info.  When complete, I switch it back to an overlay in the plan file. 
The same goes if I'm tryng to find conflicts between structure, mechanical ducts, lights and sprinklers.  We're not 3D yet on that and won't be until the entire AEC is using BIM. 

So it depends on what I need it for.