Explore the key differences between data shortcuts and external references in Civil 3D, particularly how they interact with objects and labels inside the drawing. Also, understand how changes in the drawing scale impact the scale of labels and how data references and external references are controlled by the current and the parent drawing, respectively.
Key Insights
- Data shortcuts and external references behave differently inside Civil 3D. While labels associated with data shortcuts interact and update with the objects in the drawing, labels associated with external references remain constant, controlled by the parent drawing.
- Changing the drawing scale affects the scale of labels associated with data shortcuts, but not those with external references. The latter remains at whatever scale the parent drawing specifies, regardless of changes in the current drawing scale.
- The control over data references and external references differs. The current drawing controls data references, allowing changes without needing to revert to the parent drawing. However, any visual changes to an external reference necessitate going back to the parent drawing.
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Now that we have our data shortcuts and our external reference in our drawing, we’re going to go ahead and show a couple of the differences between the two. But the first thing we’re going to go ahead and do is we’re going to place some spot elevations and some contour labels so that we can see how the objects inside Civil 3D interact versus how an external reference interacts.
So I’m going to go ahead and go up to Annotation. If you don’t have the Annotation dropdown, go ahead and type in “menubar” and then hit 1, and this menu bar will show up at the top. I’m going to go ahead and go to Surface Labels.
I’m going to go ahead and go to Contour Multiple. I’m going to hit ENTER, and I’m going to select my Civ 203 surface. So from here, I’m going to go ahead and specify my first point.
I’m going to pick up here somewhere, and then I’m going to go ahead and pick down here somewhere. When I do that and I hit ENTER to get out of that command, you’re going to notice that I have some labels. They are in fact interacting with my data references.
You can see Civil 3D is adding or modifying the orientation of those labels based on the angle of this line and the angle of the contours. I’m going to go ahead and right-click on this and select Properties. I’m going to go ahead and drop down on my Display Contour Label Line and select False so that that label line turns off.
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But what we have going on is these labels are interacting with the object that is our data shortcut. I’m going to go ahead and add in a couple of spot elevations. I’m going to do that by going to the Annotate tab of the Ribbon bar.
I’m going to go to Add Labels. I’m going to go ahead and select my surface. I’m going to select my Spot Elevation.
I’m going to go ahead and select my Spot L Label Style, and I’m going to set my marker style to None. I’m going to go ahead and click Add. And when I do that, Civil 3D is going to ask me to select my surface.
I’m going to hit ENTER, and I want to place these spot elevations on my Dev Combo surface. I’m going to go ahead and select Dev Combo. I’m going to click OK.
And now Civil 3D is going to ask me to select points. I’m going to put some spot elevations on some key geometry points for my alignments. So I’m going to do the end of this alignment in my cul-de-sac, and you’ll see 195.16. I’m going to go ahead and do the end of this alignment in this other cul-de-sac.
You can see 185.12 at that spot. I’m going to go ahead and do the intersections of my Dev Branch and my Dev Main. And I’m going to do the intersection of my Dev Branch and my Highway.
So with these labels, what you’re seeing is that these labels are referencing the objects inside of my drawing here, and they will update themselves based on where they’re in play on this drawing. So that’s not that crazy of an idea, but the differences are going to start becoming more apparent as we make some changes to the drawing. So the first thing that you can notice is that inside of my drawing, if I was to change my drawing scale or my annotation scale of my drawing—if I change my drawing scale to something extreme like 1" = 500'—you’re going to notice that my labels that I’ve placed, so my alignment labels, my spot elevation labels, my contour labels, they’re very large, whereas the labels that are associated with my XREF haven’t changed at all.
And that’s because the XREF labels are being controlled by the parent drawing rather than the current drawing. So as I change the current drawing, my labels are changing in scale, but the XREF labels are only staying at whatever the parent drawing is stating they are. If I went to 1" = 20', my scales go down, my label scales go down, but my XREF scales stay the same.
Now this becomes apparent. And the reason this is, is because if you go to Toolspace and you go to the Prospector tab, what you’re going to notice is that inside of here, like we’ve shown before, if I look at Surfaces and I look at where my data shortcuts are, I’m going to see the objects that I’ve brought into this drawing. Now if I look to where Parcels normally would be, if I look to Sites, I don’t have any option to expand.
And that’s because the Parcels that are inside of this drawing are not data referenced in. They are being 100% controlled by the parent drawing. So anything that shows up in the Prospector tab, we can control in the current drawing.
We can control how our surfaces are being displayed. If I go to Civ 203, right-click, select Properties, I can change the object style. I can change it to Design Topo and hit Apply.
And you’ll notice that my surface updates to the blue and magenta. I’m going to go ahead and change it back to Ex Topo, but Civil 3D is allowing me to control these objects in the current drawing. Whereas the objects that are XREF’d in, those are being controlled by the drawing that is the parent—that is the XREF itself.
And so what you would have to do to modify the object that you’re XREF’ing in is you would have to go to the original drawing, make the changes, come back to your current drawing, update the XREF, and then you would see those changes migrate across. It’s not as seamless. But it’s not something that we can’t work around.
And especially it’s not an option to us because you can’t data reference Parcels in. Now, when we’re talking about these scales, and we’re seeing these labels not scale up and down appropriately, that doesn’t mean that they’re not going to interact inside of Paper Space appropriately. Paper Space, and the labels that we have inside of these drawings, are relating to Paper Space based on an assumed text height. And so all of these labels—I know for a fact that the Parcel labels that are inside of this drawing—were set up as being a Paper Space height of 0.1 inches.
When I go into Paper Space, those labels—even though they aren’t part of this drawing—do look to try and be the 0.1-inch label height no matter what my scale is in Paper Space. So it’s not the end of the world that the labels aren’t updating in Model Space,
It just becomes an inconvenience rather than being a problem that I don’t have control over the labels and that I need to go rescale them every time I need to change my drawing scale. So these are just a couple of the differences.
As you work inside Civil 3D, you’ll notice some more of the differences. But the main issue, or the main difference, between external references and data references when you’re working with them is that external references are controlled by the parent drawing, and data shortcuts—or data references, as I continue to call them—are controlled by the current drawing. So you don’t have to go anywhere to make any changes to your data shortcuts.
You do have to go back to the parent drawing to make any visual changes to an external reference. Now that I’ve added in these spot elevations and my contour labels, I’m going to go ahead and save this drawing, and I’m going to go ahead and meet you in the next video.
