So a method we use a lot in AutoCAD is we use things called external references.
And.
We tend to shorten that rather than saying external references all the time.
They're known as xrefs.
Okay.
And the whole principle around Xrefs.
Well, there's a few reasons for doing it.
One is file size.
Another is just ease of change and drawing control.
And I'll go through what they are now.
So we've got this again, this is from the architectural course that we do, and this is a building
layout.
And if I go to model space, you can see we have this building here.
Now, let's suppose I was the architect and I designed this building.
All I'm concerned with is the building itself.
Somebody else, a civil engineer, a landscaper, someone's creating an office park somewhere and they're
putting in lots of different offices.
And this is just one of them.
Okay, So I'm as the architect, I'm not concerned with all the external things.
All my job involves is creating this building layout and then give it to somebody else, to the client.
Also are.
A company involved and they will take my file and they will put it in the kind of landscape of where
it's going to go, for instance.
Now the drawing is concerned with things like car parks and traffic and roads and all that stuff.
So they just want to be able to bring my.
Building.
Filing.
If I then decide to move this wall, for instance, a bit to the side, I don't need I don't want to
be phoning around all these different people who've brought my drone in and said, Oh yeah, I've changed
it, so you need to move your wall 500mm, same as I've done that.
Obviously that wouldn't work.
So the way things work and this is something you can use in your drawings, even if you're just working
for yourself, you can use this to good effect.
We have these things called external references.
So I'm going to have this new drawing.
Just set the units.
Okay?
And let's say I'm going to make this.
100m by 50m.
So this is just indicative and let's say this is kind of an office park, the area where the offices
are going, I could get the CAD file off.
The architect or whoever, and I could go, okay, I want to copy this.
I.
I mean, I could post it and I could post it as a block, So.
So it's a block.
Okay.
And I could have a few of them.
Maybe add three like that.
And maybe.
Yeah.
So the three offices were there.
But then if something changes, I need to get that drawing again and I need to insert it again.
I need to make sure I've done that, which means if something changes, they have to let everyone it
just becomes a nightmare.
In terms of file management.
It also means this drawing.
Now, I might have a lot of detail in this drawing in terms of landscaping and roads and that kind of
thing.
The drawing could get fairly large in terms of file size.
Well, it's going to get even larger when I bring in all these offices because they also contain information
on lights and windows, things I don't need.
So my when you go down, I might then send my file to someone who puts it into an even bigger site layout
and you can end up with huge file sizes because you've got all this information.
So the best way to do it is to use what's known as Xrefs and it's under the insert command and as usual,
the best way to kind of explain this is just to show it in use.
So we have these references here and I'm going to go to attach.
And when you go to touch, you'll get a dialog box.
It's asking you for a file, but you can attach all sorts of things for default.
Here it's an image files, but I can attach all different CAD files.
And what I'm looking for here is a DWG, which is a AutoCAD file.
Okay, so now I can select.
The building drawing that the architect sent me.
In this case, it's our office layout.
So I'm going to open that.
And I get some options here.
First thing it's asking is scale.
Now, if a join you've been sent is an actual drawing to scale, you shouldn't have to change this.
Okay?
You should leave it set just as one insertion point.
Again, if the architect has created the office layout in actual coordinate space in the correct coordinates
in the world in terms of where it needs to be, then you wouldn't need to.
You would just want it to come in where it where it comes in.
But most of the time you'll be specifying on screen rotation.
Again, I would say specify that on screen.
Okay.
And let's click okay.
Now it's it's just like when we clicked on paste, we get the option to bring in our office and to rotate
it.
We can turn off or on, but I want it there.
Okay.
And I'm going to right click.
And I can copy that.
There we go.
And you might notice it's kind of grayed out now.
That shows us that it's an Xref and what an Xref has done.
It hasn't inserted any of this information in our actual drawing.
What it's done is it's, it's said to AutoCAD when you open this drawing.
Go and open these other drawings in the background.
So the separate files that are loading in and displaying in the background, but the information is
not stored in this join, it still remains in the original.
Okay.
So hopefully that makes sense.
I'm going to show you now if I type in Xref.
And you can bring up this box, which is the x ref manager.
And this is where you can manage all the X refs in your join and some joins big joins can have many
X refs.
So we've got this here building one.
This is x ref we've just pulled in and when you click on it, it highlights just to show you which one
it is and it's saying the path where it was found.
This is just a path on my computer.
Yours, if you're doing similar, will be different.
But basically you can see it's loading in a different drawing.
Okay.
When we load this drone.
So when you go to open it, AutoCAD opens this file drawing far and then it goes the xrefs here and
it loads in these and displays them in the background.
And it's important to note that it's just displaying it.
Okay.
Now I, if I just, I can open this xref by right clicking it and it opens it and you can see that it
is a different drawing.
So let's say I'm the architect and I decide for whatever reason, there's going to be a big circle there.
I don't know what it is.
It doesn't matter, but I'll say that.
So I change that.
I'm going to email it out to everyone involved.
That's all the architect needs to do.
Now I open my drawing and when I open it AutoCAD.
Realizes that it's out of date.
So it says an x ref was modified.
And it would pick that up because I would have got the drawing from the architect and saved it over.
Okay.
The other one.
So if you miss that, um, message there.
You can see down here.
You get this tub manager extra.
Okay.
Which is your manager?
Same as typing in x ref.
And I get a little comment here saying it needs reloading.
So because I saved over it, it's realized that this one that I'm displaying here, it's not the latest
file.
All I need to do is right click and go to reload and it will save a references changed.
You can even compare the differences.
Okay.
If I was to click yes.
See, it's this kind of cloud around it.
It's detected what is new and it's showing me what is new.
Okay.
And I'm going to select.
Okay.
I'm not, by the way, is brilliant.
It never used to do that in older versions.
This is something that came in fairly recent versions and it's a great way of seeing what's changed.
So now all my xrefs have updated.
I've still not got any of this information saved in this actual drawing.
It's loading it in the background.
Now, you do need to make sure I would have had to save over the file I'd used as the Xref with the
latest file for all that to happen with some file management going on.
It depends how you want to do that.
If you wanted to keep it different you might have had to reinsert re kind of define the file, but this
is just an overview of how xrefs work, and that is a general principle.
It's for bringing in other drawings that are other models, sorry, that remain external to your model,
but don't bring in intelligence and information into your file.
They don't increase your file size.
It just says to this drawing when you open load this other drawing in the background and put it here.
And it's.
It might seem complicated.
I get it.
If you're just doing something for yourself in your own office, it might seem unnecessary, but it's
a good way of managing things that change a lot.
Because you don't have to keep remembering which of the joins you inserted it in and then maybe you
forgot one and you're like, oh that's that's the wrong that's the out-of-date version.
All you need to do is if you've got a drawing that you've inserted in lots of other drawings, for instance,
you only if you've done it as extra, if you only change that one drawing once and it will automatically
update when you open the other drawings, or at least it will tell you about it.
Okay, so that's xrefs.
Again, it can be one of those things.
Some people struggle to get their head around it.
It's fairly simple principle.
When you break it down, the best way is get used to using them.
If you go into industry, you'll definitely use them, I would say these days, but just get used to
using them yourself and it will become clear.
Okay, so that's xrefs.