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So a method we use a lot in AutoCAD is we use things called external references.

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And.

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We tend to shorten that rather than saying external references all the time.

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They're known as xrefs.

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Okay.

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And the whole principle around Xrefs.

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Well, there's a few reasons for doing it.

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One is file size.

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Another is just ease of change and drawing control.

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And I'll go through what they are now.

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So we've got this again, this is from the architectural course that we do, and this is a building

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layout.

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And if I go to model space, you can see we have this building here.

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Now, let's suppose I was the architect and I designed this building.

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All I'm concerned with is the building itself.

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Somebody else, a civil engineer, a landscaper, someone's creating an office park somewhere and they're

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putting in lots of different offices.

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And this is just one of them.

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Okay, So I'm as the architect, I'm not concerned with all the external things.

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All my job involves is creating this building layout and then give it to somebody else, to the client.

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Also are.

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A company involved and they will take my file and they will put it in the kind of landscape of where

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it's going to go, for instance.

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Now the drawing is concerned with things like car parks and traffic and roads and all that stuff.

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So they just want to be able to bring my.

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Building.

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Filing.

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If I then decide to move this wall, for instance, a bit to the side, I don't need I don't want to

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be phoning around all these different people who've brought my drone in and said, Oh yeah, I've changed

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it, so you need to move your wall 500mm, same as I've done that.

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Obviously that wouldn't work.

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So the way things work and this is something you can use in your drawings, even if you're just working

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for yourself, you can use this to good effect.

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We have these things called external references.

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So I'm going to have this new drawing.

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Just set the units.

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Okay?

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And let's say I'm going to make this.

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100m by 50m.

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So this is just indicative and let's say this is kind of an office park, the area where the offices

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are going, I could get the CAD file off.

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The architect or whoever, and I could go, okay, I want to copy this.

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I.

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I mean, I could post it and I could post it as a block, So.

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So it's a block.

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Okay.

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And I could have a few of them.

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Maybe add three like that.

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And maybe.

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Yeah.

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So the three offices were there.

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But then if something changes, I need to get that drawing again and I need to insert it again.

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I need to make sure I've done that, which means if something changes, they have to let everyone it

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just becomes a nightmare.

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In terms of file management.

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It also means this drawing.

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Now, I might have a lot of detail in this drawing in terms of landscaping and roads and that kind of

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thing.

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The drawing could get fairly large in terms of file size.

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Well, it's going to get even larger when I bring in all these offices because they also contain information

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on lights and windows, things I don't need.

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So my when you go down, I might then send my file to someone who puts it into an even bigger site layout

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and you can end up with huge file sizes because you've got all this information.

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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,

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the best way to kind of explain this is just to show it in use.

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So we have these references here and I'm going to go to attach.

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And when you go to touch, you'll get a dialog box.

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It's asking you for a file, but you can attach all sorts of things for default.

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Here it's an image files, but I can attach all different CAD files.

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And what I'm looking for here is a DWG, which is a AutoCAD file.

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Okay, so now I can select.

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The building drawing that the architect sent me.

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In this case, it's our office layout.

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So I'm going to open that.

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And I get some options here.

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First thing it's asking is scale.

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Now, if a join you've been sent is an actual drawing to scale, you shouldn't have to change this.

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Okay?

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You should leave it set just as one insertion point.

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Again, if the architect has created the office layout in actual coordinate space in the correct coordinates

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in the world in terms of where it needs to be, then you wouldn't need to.

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You would just want it to come in where it where it comes in.

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But most of the time you'll be specifying on screen rotation.

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Again, I would say specify that on screen.

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Okay.

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And let's click okay.

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Now it's it's just like when we clicked on paste, we get the option to bring in our office and to rotate

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it.

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We can turn off or on, but I want it there.

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Okay.

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And I'm going to right click.

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And I can copy that.

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There we go.

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And you might notice it's kind of grayed out now.

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That shows us that it's an Xref and what an Xref has done.

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It hasn't inserted any of this information in our actual drawing.

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What it's done is it's, it's said to AutoCAD when you open this drawing.

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Go and open these other drawings in the background.

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So the separate files that are loading in and displaying in the background, but the information is

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not stored in this join, it still remains in the original.

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Okay.

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So hopefully that makes sense.

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I'm going to show you now if I type in Xref.

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And you can bring up this box, which is the x ref manager.

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And this is where you can manage all the X refs in your join and some joins big joins can have many

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X refs.

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So we've got this here building one.

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This is x ref we've just pulled in and when you click on it, it highlights just to show you which one

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it is and it's saying the path where it was found.

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This is just a path on my computer.

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Yours, if you're doing similar, will be different.

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But basically you can see it's loading in a different drawing.

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Okay.

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When we load this drone.

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So when you go to open it, AutoCAD opens this file drawing far and then it goes the xrefs here and

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it loads in these and displays them in the background.

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And it's important to note that it's just displaying it.

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Okay.

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Now I, if I just, I can open this xref by right clicking it and it opens it and you can see that it

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is a different drawing.

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So let's say I'm the architect and I decide for whatever reason, there's going to be a big circle there.

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I don't know what it is.

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It doesn't matter, but I'll say that.

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So I change that.

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I'm going to email it out to everyone involved.

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That's all the architect needs to do.

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Now I open my drawing and when I open it AutoCAD.

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Realizes that it's out of date.

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So it says an x ref was modified.

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And it would pick that up because I would have got the drawing from the architect and saved it over.

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Okay.

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The other one.

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So if you miss that, um, message there.

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You can see down here.

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You get this tub manager extra.

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Okay.

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Which is your manager?

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Same as typing in x ref.

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And I get a little comment here saying it needs reloading.

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So because I saved over it, it's realized that this one that I'm displaying here, it's not the latest

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file.

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All I need to do is right click and go to reload and it will save a references changed.

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You can even compare the differences.

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Okay.

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If I was to click yes.

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See, it's this kind of cloud around it.

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It's detected what is new and it's showing me what is new.

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Okay.

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And I'm going to select.

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Okay.

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I'm not, by the way, is brilliant.

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It never used to do that in older versions.

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This is something that came in fairly recent versions and it's a great way of seeing what's changed.

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So now all my xrefs have updated.

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I've still not got any of this information saved in this actual drawing.

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It's loading it in the background.

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Now, you do need to make sure I would have had to save over the file I'd used as the Xref with the

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latest file for all that to happen with some file management going on.

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It depends how you want to do that.

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If you wanted to keep it different you might have had to reinsert re kind of define the file, but this

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is just an overview of how xrefs work, and that is a general principle.

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It's for bringing in other drawings that are other models, sorry, that remain external to your model,

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but don't bring in intelligence and information into your file.

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They don't increase your file size.

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It just says to this drawing when you open load this other drawing in the background and put it here.

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And it's.

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It might seem complicated.

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I get it.

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If you're just doing something for yourself in your own office, it might seem unnecessary, but it's

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a good way of managing things that change a lot.

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Because you don't have to keep remembering which of the joins you inserted it in and then maybe you

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forgot one and you're like, oh that's that's the wrong that's the out-of-date version.

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All you need to do is if you've got a drawing that you've inserted in lots of other drawings, for instance,

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you only if you've done it as extra, if you only change that one drawing once and it will automatically

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update when you open the other drawings, or at least it will tell you about it.

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Okay, so that's xrefs.

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Again, it can be one of those things.

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Some people struggle to get their head around it.

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It's fairly simple principle.

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When you break it down, the best way is get used to using them.

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If you go into industry, you'll definitely use them, I would say these days, but just get used to

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using them yourself and it will become clear.

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Okay, so that's xrefs.