It’s that time of year again, it’s getting warmer out, days are getting longer (assuming you’re in the northern hemisphere), and we get new software to play with. Autodesk has just released a whole bunch of new software, including Civil 3D. Want to know what’s new? Well, just keep reading.

If I know of an issue with one of the new features, I’ll put in a GOTCHA so watch out for those.
For each feature, I’ll also include a Workflow Idea. These will give you an idea on how to leverage the new feature in your workflows. If you have other ideas, let us know in the comments.

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Bad News – New File Format

First off, there is some bad news. AutoCAD 2018 introduced a new drawing format which means Civil 3D is not backwards compatible. This honestly comes as a surprise to me, not that they made a new version, but that they kept the prior version for so long. For those of you fairly new to the AutoCAD/Civil 3D world, new drawing versions typically came out every third release or so. The last version of AutoCAD that had a drawing format change was 2013.

Version.png

Civil 3D 2018 is built on the AutoCAD 2018 file format

Civil 3D on the other hand would have a new object format every single version. We never had any options of backwards compatibility. In 2014, that changed. You could save a Civil 3D 2016 version back to 2013, 2014, or 2015. 2017 saw a new object format which made Civil 3D not backwards compatible and 2018 has both a new drawing format and a new object format so it’s double not backwards compatible.

The reason I bring this up, if one person on the project team decides to upgrade to Civil 3D 2018, the entire project team will need to upgrade. Also, if you install 2018 to test out some of the new features, don’t do it on an active project.

Now let’s get into the good stuff. What’s awesome about the 2018 release?

Offset Profiles

We’ve had Offset Alignments for a while now. You know, create an Offset Alignment, adjust the centerline alignment and the Offset Alignments adjust too. You could then create profiles on those Offset Alignments (say for example to have a 2% cross slope) but if you change the offset value, the profile is no longer at 2%. Likewise, if the centerline profile changes, you’ll need to go manually change the profiles to maintain that 2% cross slope. Well, NO MORE! Offset Profiles will do that for you!

When you create the offset alignment, you’ll see an option to also create offset profiles. You simply put in the desired cross slope and when it creates the alignment, the alignment will have a profile that’s dynamic to the parent profile. Change the parent profile, the offset profile changes. If the parent profile has vertical curves, the offset profile will also have vertical curves.

Offset_Profiles.png

Create Offset Profiles when you create Offset Alignments

GOTCHA
I’m not exactly sure how the offset profile vertical curves are calculated but they always seem to be there. A possible issue is if you have a vertical curve that is part way in a horizontal curve. If you offset that profile at a 2% cross slope, the resulting profile should not have a parabolic curve. If it does have a parabolic curve, then it’s not a true 2% cross slope. In other words, verify you get the results you want!

If you want to edit the offset parameters, select the offset alignment and choose, “Offset Profile Parameters” on the ribbon. This will bring up a dialog box that you can go edit those parameters as well as add transitions to the offset profile.

For example, perhaps you need a 2% cross slope for the first 200’ of the alignment and then over the course of 50’ you want to transition to a 4% cross slope and then maintain that to the end. In the Offset Parameters tab of the offset profiles properties, you can simply add in additional cross slope regions.

Edit_Offset_Profiles.png

Edit Offset Profiles

GOTCHA
There seems to be an issue with the slope transitions if the parent profile has a PVI within the transition region. Hopefully this will be fixed soon. I would recommend everyone creating a support request for this so we can get it fixed quickly.

Workflow Ideas
So, how can you use this tool to improve your productivity? Just the other day, I had a client ask me how to apply superelevation to an alignment on a trail so he could control the cross slope of the trail (he didn’t want it to slope into the hill as it switched back and forth down the hillside). Using these tools, you can simply create those offset profiles, add in the cross slope regions, and target your lane to the alignment and profile and you’re done. Need to adjust the cross fall for a specific region? Just adjust the cross slope region on the offset profile!

Connected Alignment

Connected alignments are basically an alignment/profile filet. Have two intersecting alignments that you want to put another alignment curved between them yet always tangent to them? Well, this is the tool you want. Simply select the two alignments, pick in the quadrant you want the connected alignment, specify a few values, and you have the connected alignment. One of the options when creating the connected alignment is to create a connected profile as well. The profile will match the elevations of the parent profiles where the two coincide and then transition to match the other profile at the other end.

Connected_Alignments.png

Choosing the Quadrant for the Connected Alignment

Connected_Alignment_Options.png

Options When Creating Connected Alignments

Connected_Alignment_with_Profile.png

Connected Alignment with Profile

 

GOTCHA
 The two alignments that you want to create a Connected Alignment between must intersect each other. In certain situations, where you might have a non-perpendicular T intersection, the two offset alignments might not intersect each other. In this case, you won’t be able to create a Connected Alignment between them.

Connected_Alignment_Gotcha.png

Unable to Create Connected Alignments Here

Workflow Ideas
A long long time ago, Autodesk introduced the ability to automate intersection design in Civil 3D however, it only worked well for extremely simple intersections. If things get complex, you’ll need to manually create the intersection. In that case, these tools are ideal!

Extracted Featurelines as Baselines

We’ve been able to extract featurelines from a corridor for quite a while now. Last year, you could also use a featureline as a baseline in a corridor but what you couldn’t do is extract a featureline from a corridor and then add it back into the SAME corridor as a baseline.

In 2018, that limitation has been removed. Extract a featureline and simply add it back into the same corridor as a baseline.

Extracted_Featureline_as_Baseline.png

On the left, a single baseline                                                                           On the right, two baselines, one the centerline, one extracted edge of asphalt

Workflow Ideas
One of the issues I’ve seen with corridor modeling is in the area of lane widening. If I have a lane that widens out and has a sidewalk, if I use one assembly, the width of the sidewalk is calculated relative to the baseline, not the edge of the road. In a case like this, you’ll end up with a sidewalk that isn’t as wide (relative to the edge of road) as it should be. So what do you do? Extract the featureline from the edge of the road and add it back as a baseline to the corridor. To that, attach an assembly that contains the curb, walk, and daylight (or whatever subs you are using) and you’re done!

Corridor Bowtie Cleanup Optional

Introduced into Civil 3D 2017, corridors will now cleanup those nasty bowties for you automatically (in certain instances). Now, in 2018, you can choose whether or not Civil 3D will clean those up for you. On the Settings tab of the Toolspace, right click on Corridor and go into the feature settings. In the feature settings you’ll see new options for the bowtie options. You can choose if you want them to clean up the Tangent-Tangent situations or the Tangent-Arc (and Arc-Tangent) situations independently. Oh, and by the way, IT CLEANS UP TANGENT-ARC INTERSECTIONS NOW!!!!!

Bowtie_Cleanup_Options.png

Bowtie Cleanup Option

Workflow Ideas
I’m not exactly sure why you would want to turn this off but apparently there were people asking for it and so Autodesk included it as an option. I’m all down with options so I’m not going to complain, I just can’t think of a situation where I would want to turn this off. If you can think of one, please leave me a comment.

Daylight Bowties

The bowtie cleanup, as introduced in 2017, was a huge step forward but it wasn’t quite complete. It only worked between two tangents (straight lines) and only worked for links that had a constant width. In other words, the daylighting didn’t clean up. In 2018, they have given you a tool that cleans it up for you. You simply select the alignment piece before the cleanup and the alignment piece after the cleanup and then pick the point you want them to cleanup to. There’s also a tool to remove the cleanup if you want to change it up.

Clear_Bowties.png

GOTCHA
If the design changes, you’ll have to remove the cleanup and reapply it. The tool will continue to cleanup to the same location even if, after the design change, it’s no longer needed.

Workflow Ideas
I kind of think this one is a no brainer. We’ve all done designs where the inside corners of our corridors didn’t work and we would have to extract featurelines and use the grading tools or manually grade in that area. No more, just use the bowtie cleanup tool and you’re done!

Featureline Elevations Relative to a Surface

Featurelines – I love featurelines. Their ability to adjust with other featurelines is just amazing! New in 2018, you can set featurelines to be dynamic to a surface. If the surface changes, the featureline changes! When you create a featureline from objects or assign elevations to it (either through the command or the Elevation Editor), you can choose a surface as well as the relative elevation that you want them to be relative too. You can also adjust the relative elevation for each individual vertex of the featureline.

Create_Featurelines_From_Objects.png

Create Featurelines from Objects

Elevation_Editor.png

Elevation Editor

GOTCHA
Not a serious gotcha here but, I think you should be aware, a featureline can only reference one surface. If you need a featureline to be relative to two different surfaces, you’ll need to split it into multiple featurelines.

Workflow Ideas
I’m really excited about this one. The area I see it being used really well is for ADA ramps. You know the front of the ram needs to be 6” below the sidewalk and the back of the ramp needs to be at the top of the sidewalk. Create your featurelines that represent the ramp, set the relative elevations, create a surface from it  (I’m not sure if I would do one surface per ramp or put them all in the same surface with multiple boundaries, I’ll have to do some testing on it), and then past both the original surface and the ramp surface into a new surface. If the design of the sidewalk changes, the ramp immediately updates too (just double check to make sure it still meets the requirements).

Sections

If you’ve ever worked with sections, you know that what Civil 3D produces is typically not enough for constructions. The sections need additional annotation, blocks, and linework. The problem is, if you move the section views, or if the section views get rearranged automatically, the Autocad objects don’t move with the views, until now. Section Views now have a buffer property. Any AutoCAD objects within the buffer will move with the section view.

Section_View_Buffer.png

Section View Buffer

GOTCHA
If you adjust the buffer around a section view to include new objects or exclude existing objects, the objects won’t know the buffer has changed until they (the objects) have been edited. Just do a move from 0,0,0 to 0,0,0 and they will re-identify with being inside or outside the buffer.

You can also add new Section Views to a View Group. In the past, if you needed to add a new sample line in between two sample lines, you would have to either manually update the section views to account for the new view or delete them all and recreate them. In 2018, you can simply create the section view and then add it into an existing view group.

Move_To_Section_View_Group.png

Move to Section View Group

Workflow Ideas
For those of you that do roadway design, this one is huge! It doesn’t really create any new workflows, it just greatly simplifies the ones we already have. Need to add a cross section for a new culvert that wasn’t originally planned? Create the sample line, create the view, and add it to the view group. When the layout of the section views updates, any AutoCAD objects in the views will move with the view.

Plan-Plan and Profile-Profile

The plan production tools have been out for ages now and have been pretty much untouched, until now. In 2018 you can now create Plan-Plan sheets and Profile-Profile sheets. The process is pretty much the same, the only difference is in the template that you use to create the sheets. In the template, create the two (or however many you need)  viewports and in the properties, set them to the correct type (i.e. plan or profile), and then give them the correct order. The viewports have a new property called “Viewport Order”. The viewport you want to use first will have the Viewport Order=1, the second will have the Viewport Order=2, etc.

Plan-Plan.png

Plan-Plan Production showing the properties of the lower viewport

GOTCHA
The viewports need to have the same dimensions (at least as far as the length of the viewport goes). I tried creating a template with one long viewport and then under that a shorter viewport and it failed. The length of the profile views was calculated using the shorter viewport. I haven’t tested it much but it’s something to be aware of.

Workflow Ideas
I haven’t really come up with any new workflow ideas for this one. Like the section view improvements, it just greatly simplifies the ones we have. In the past, I would create a viewport that was twice as long as I needed and then manually copy it and crop it in order to get the Plan-Plan or Profile-Profile. This just makes the process much easier.

Conclusion

So, what do you think? Which of these are you most excited about? Which one do you think will improve your processes the most? Was there something I missed? I would love to hear your thoughts about the new release. Just leave a comment and let the world know!

I’ve always complained about the highlighting of objects in the QTO Manager, they just aren’t obvious enough! Ok, to be honest, I’ve never actually complained about it to anyone but myself and that’s probably why I just found this out.

So, what’s the problem? Well, if you have objects in your drawing that have a pay item assigned to them, you can have the QTO manager highlight them for you. Problem is, they highlighting isn’t very obvious…

Which objects are highlighted?

Which objects are highlighted?

Well, it turns out that you can control how much the objects that aren’t highlighted are faded back. This setting is found in the AutoCAD options on the Display tab in the Fade control section. The variable you want to adjust is the “In-place edit and annotative representations”. I know, duh! Of course that’s where you should look for this!

AutoCAD Options

AutoCAD Options

Change that variable, say to 3o, and this is what your drawing will look like:

Ah! Much better!

Ah! Much better!

Thanks to Cody with ECS in Wyoming for sharing this with me. I love learning things from my students!!!!

 

As many of my posts start out, this one comes from one of my clients. He was using the Pressure Networks in Civil 3D 2015 and noticed that when he added the inner diameter of the pipe to a label, it came up with question marks.

Question Marks for Inner Diameter

Question Marks for Inner Diameter

To add to the confusion, even though there is a property in the pipe object for inner diameter, it was grayed out and couldn’t be changed.

Inner Diameter Can't be Edited

Inner Diameter Can’t be Edited

So, this got me to thinking, there’s got to be some way to add that information to the pipe! Well, let’s go edit the catalog. If you aren’t familiar with it, you can edit your pressure network catalog using the Content Catalog Editor.

To open your Content Catalog Editor, go to your Windows Start Menu and find the location where you can start Civil 3D, there you will also see the Content Catalog Editor.

Content Catalog Editor Start

Content Catalog Editor Start

In the Content Catalog Editor (CCE), open your pressure network catalog. Civil 3D comes with three of them, choose the one you are using or the one you’ve created for your company. In this example, I’ll use the pushon catalog. By default, they can be found here for the imperial catalogs: C:\ProgramData\Autodesk\C3D 2015\enu\Pressure Pipes Catalog\Imperial. Change the obvious for metric.

Once the catalog is open, go to your pipes, and add the property for your inner diameter.

Edit the Inner Diameter

Edit the Inner Diameter

One thing to note, most 8″ pipe does not have an inner diameter of 8″. One manufacturer of C900 PVC pipe had 8″ PVC that varied from 7.26″ to 8.28″ depending on the pressure classification.

Now that the catalog has been modified, you’ll need to restart your Civil 3D and replace the pipes in your drawing that are missing the inner diameter. Unfortunately, I don’t know of a way to update the pipes that are in the drawing already (with the missing inner diameter) to show the new inner diameter in the catalog.

 

 

So, you want to bring a surface from Civil 3D into Revit? It’s pretty easy, provided you have both Civil 3D and Revit Structure. What? You don’t have them both? You only have Civil 3D? Are you sure? Recently, anyone that had Civil 3D on subscription was automatically upgraded to the Infrastructure Design Suite Premium and, guess what, it has Revit Structure! So most likely, unless you specifically opted out of the upgrade, you have access to Revit Structure.

Please read this entire post as there is some very important information near the end. First, I’ll tell you how to Import the Surface and then I’ll tell you about the Limitations and Issues.

Import the Surface

The Bridge Modeling Tools have been around for a while now. If you haven’t installed them yet, go to the subscription website and download them. You’ll need both of them, one for Revit Structure and one for Civil 3D.

After you have installed them, simply open the drawing that has the surface in Civil 3D and then open the file in Revit Structure you want to bring the surface into. In Revit, there is a little bit of setup you need to do (if you’re a Revit person, you probably already know this stuff). Go to your “default 3D view” (that’s the “doghouse” on the quick access toolbar) and edit the Visibility/Graphic Overrides.

Setting Up Revit

Setting Up Revit

In the Visibility/Graphics Overrides, turn on the display of the Topography.

Topography Options

Topography Options

This will allow you to see the surface when you bring it in. Once Revit is set up (I’m sure there are some settings I’m not aware of and I’m sure a Revit Guru will correct me on this), go to the Extensions tab, expand out the Civil Structures tool and choose “Integration with AutoCAD Civil 3D”.

Integrate with Civil 3D

Integration with Civil 3D

If you have more than one drawing open in Civil 3D, you’ll need to choose the drawing with the surface in it, the surface(s) in the drawing you want to import, and then have it import the surface into Revit.

Import Settings

Import Settings

After hitting OK, you then have some options when importing the surface, such as the material that will be assigned to the surface and the limits of the surface (if you don’t want the entire thing).

Terrain Definition

Terrain Definition

Once done, you’ll have a surface in Revit that you can do whatever you want to with it.

Surface in Revit

Surface in Revit

Limitations and Issues

This tool is really, I mean REALLY cool! A few years ago, one of my coworkers (Brian Mackey) and I worked up a technique to do this very thing and believe me, it wasn’t this easy. This is easy but, you need to know what it does. If I take this surface in Revit and I compare it to the surface in Civil 3D (I’ve stylized it in C3D to be similar to what we see in Revit) you’ll see they are quite different.

Civil 3D vs. Revit

Civil 3D vs. Revit

As you can see, the limits of the surface from Civil 3D aren’t honored in Revit. In fact, the only thing that comes through in Revit is the surface points. If you have added any breaklines or boundaries to the surface in Civil 3D, Revit doesn’t recognize those. For you civil folks, to get a feel for what Revit is doing, basically extract the surface points from a surface and then add them to a new surface and that’s what you will have in Revit. This is still better than what we had though so it’s definitely an improvement. If this is important to you, file a support request with Autodesk so they know and perhaps they will adjust the way the tool works (the method Brian Mackey and I developed has the same issue by the way).

I WANT YOU TO MAKE THE SURFACE LOOK PRETTY!!!!!

Yes, we’ve all heard it before, Civil 3D makes contours that sometimes look like the recording of an earthquake on a Seismometer:

Seismometer Recording

Seismometer Recording

Really, it’s not the fault of Civil 3D, it’s the data. Add the same data to any other civil design program and you’ll get the same results. This seems to crop up quite a bit when you have cross grades. In the following image you can see that there are two roads going opposite directions and this is where the jagged contours are coming from:

Jagged Contours

Jagged Contours

No contractor would build it this way so, let’s see what our options are.

Option 1: Smooth the Contours

You can smooth the contours of the surface. In the style the surface is using, you can toggle on the option to smooth the contours. This is a great way to make a drawing “look pretty”. It will take the contours and smooth them out. This is only editing the display of the surface. If you have a profile through this area, smoothing contours does nothing to the profile because we aren’t smoothing the surface, we are smoothing the display of the surface.

To smooth the contours, go into the style the surface is using and, on the contours tab, toggle the option to smooth the contours to True. Once you have this toggled on, you can select the type of smoothing you want to apply to the surface as well as how aggressive you want the contour smoothing to be. Play around with these settings and see what looks best for you. There isn’t a correct setting for this because your goal, when smoothing contours, is to make the contours look pretty.

Contour Smoothing Options

Contour Smoothing Options

And here is the same area of that surface with the contour smoothing option set to True, the Smoothing Type set to “Add Vertices” and the contour smoothing maxed out.

Surface with Smoothed Contours

Surface with Smoothed Contours

There are some things to be concerned with when smoothing contours, you are sacrificing the accuracy of the contours to make them “look pretty”. If you have a spot elevation that happens to fall very close to a contour or perhaps a point that was used in the surface creation that’s really close to the contour elevation, you might see some discrepancies. In the following image, I placed a spot elevation and snapped to the contour and you can see it’s not the exact same elevation as the contour:

Smoothed Contours Labeled

Smoothed Contours Labeled

Another issue with smoothing contours is you might end up with contours that cross each other. You’ll see this sort of thing primarily where you have some really steep areas such as retaining walls.

Crossing Contours

Crossing Contours

Anyone that’s done any amount of surface modeling knows this is not allowed.

The last issue that I’m aware of with smoothing your contours is, it’s all or nothing. You can’t smooth just a portion of the contours of your surface. This is because it’s a part of the style.

Option 2: Smooth the Surface

The other option is to smooth the surface directly. This is an edit that is done to the surface and is found in the same place you can raise/lower the surface or paste in another surface.

Smooth Surface Command

Smooth Surface Command

There are two options when smoothing surfaces, “Natural neighbor interpolation” and “Kriging”. I’m not going to go into detail on how the different methods work or what settings to use. You’ll need to read the HELP FILE and do your own research to find out which method works best for your situation. In this example, I’m going to use the natural neighbor interpolation method.

Smothing Options

Smothing Options

So, how does this differ from smoothing the contours? Well, when you smooth contours, you are smoothing the display of the surface. When you smooth the surface, you are actually editing the surface and not just the display. Here is an image of the surface with the smoothing edit applied to it:

Smoothed Surface

Smoothed Surface

As you can see, the contours look much different then when the contour smoothing was applied. If you take a look at the triangles of the surface, you can get a better idea of what happened here (I did a 5′ grid in this example):

Smoothed Surface Triangles

Smoothed Surface Triangles

A couple things to note here, I didn’t smooth the entire surface, just the  area that needed it. Second, any data that was added to the surface was not modified in any way at all. If there are points, or breaklines, or corridors, or gradings, they are preserved (including the triangulation along the breaklines). This only affects the way the triangulation in the areas between data are calculated. Basically, instead of doing a straight grade between one point and the next, it rounds it out.

Something to be aware of, this can add a LOT of data to your surface and can make it very slow to work with so play around with the settings and get the results you want without adding too many points to the surface.

Hopefully this helps out when someone is complaining about your ugly contours!

Civil 3D uses a Triangulated Irregular Network (TIN)  for surface models, just like every other piece of civil engineering software that I’m aware of. There a  couple of major limitation to a TIN that you should be aware of. First, every single horizontal location (i.e. every x,y coordinate) can have only one elevation. This means no vertical faces and no overhangs or undercuts. The other limitation is since it’s made up of a bunch of triangles, you can’t have curves in your surface. If you have curved data that you want to add to your surface, you must approximate this with straight line segments, and this is where the mid-ordinate distance comes into play.

What the Mid Ordinate Distance Is

When you add data to your surface, one of the options is the mid-ordinate distance. What the heck is the mid-ordinate distance? Well, it’s the distance from the midpoint of a curve to the midpoint of the arc.

Mid Ordinate Distance

Mid Ordinate Distance

When you add something like a curve to your surface as a breakline, boundary, or contour; the surface cannot follow the curve so it uses the Mid Ordinate Distance to approximate the curve. Basically what happens is C3D will start at the end of the curve and draw a line to another point on the curve so the mid ordinate distance between those two points on the curve equal what is set in the dialog box.

Mid Ordinate Calculated

Mid Ordinate Calculated

As you can see in the image, there is a little bit left over at the end, when you add this to a surface, you don’t want that little bit left over so Civil 3D then evenly distributes the number of points added to the feature along it. This will result in a final Mid Ordinate Distance slightly less then what was calculated.

Mid Ordinates Distributed Along Curve

Mid Ordinates Distributed Along Curve

So, instead of adding just the ends of the curve to the surface, the Mid Ordinate Distance allows us to determine how many points along the curve we want to add.

What Should You Set It To?

Now that you know what it is, what should it be set to? In the default template, it’s value is set to 1 drawing unit (1′ in the imperial template and 1m in the metric template). Is this value too big? Too small? Or just right? Let’s think of this in a different way. Don’t think of it in the abstract Mid Ordinate Distance way, think of it instead as “How far away from my data should I allow my surface to be created?” If you set the Mid Ordinate Distance to 1′, then the triangle of your surface can be up to 1′ away from the actual data. It’s your call, is this acceptable or not?

Here’s how I like to figure out an acceptable Mid Ordinate Distance. What is the smallest distance between any two breaklines you’ll have in your surface? Are you modeling a haul road for a mine? Or are you modeling curb and gutter for a commercial parking lot? In my experience (primarily land development) I use a lot of curb and gutter. When I model the flow line and the top face of curb in a standard curb and gutter, that’s a horizontal distance of 2″. Take that smallest distance and cut it in half to get your desired Mid Ordinate Distance, in this case 1″. Since 1″ is about 0.08333 I will typically us 0.1′.

Can I Change the Default?

Well, of course you can! Ok, let me rephrase that, if you are using Civil 3D 2010 or later you can. On your toolspace, go to the Settings tab and expand out Surface and Commands:

Command Settings Location

Command Settings Location

As shown in the image, there are three commands (at least that I know of) that can have the Mid Ordinate Distance set, AddSurfaceBoundaries, AddSurfaceBreaklines, and AddSurfaceContours. Right click on the command you want to change and choose Edit Command Settings. In the command settings, expand out “Add data options” and change the “Default mid-ordinate distance” setting.

Mid Ordinate Distance Defaults

Mid Ordinate Distance Defaults

Hopefully this will help you understand what’s going on with this setting and, have a Merry Christmas!

A while back, I did a post about bringing DEM data into AutoCAD Civil 3D (you can read it HERE if you are interested). In the comments, people have asked several questions and have had some issues. One of the issues is, you have to know what coordinate system the DEM file is using. Another is that, no matter what coordinate system you are using, the DEM comes in as though the elevations where in meters (and will then convert those meters to feet).

Well, all that’s about to change. If you have the Autodesk Infrastructure Design Suite (Premium or Ultimate) then you also have Autodesk Infrastructure Modeler (AIM). You can use AIM as a DEM to Civil 3D surface converter. Simply import your DEM file into AIM, export to a .imx file, and then import that into Civil 3D.

Open up AIM and create a new project. Give it a name and a place to save it. Keep the coordinate system as LL84 (there’s no need to change it) and leave everything else the way it is.

Create a new project

Once the project is created, import the DEM file into AIM. This is done through the Data Sources panel. Expand out the different data sources and choose “Raster” as the data source. Browse to your DEM file, open it, and then Refresh the data. You will now have a beautiful surface in your model.

Import DEM as Raster

Refresh DEM

Now that the DEM is added to your model, export it out to Civil 3D via the .imx file. In the application menu of AIM (that’s the purple I in the top left corner of the application), choose the Export menu and then “Export to IMX”. In the Export to IMX dialog box, choose to export the entire model, and give it a file name. AIM will choose an appropriate coordinate system so just leave that alone. Depending on the size of the DEM file, this could take a few minutes.

Export to IMX

Once the .imx file is created, open Civil 3D. To import the .imx file, it’s important to remember to assign a coordinate system to your drawing. If you aren’t sure how to do this, click HERE. Once in Civil 3D choose the Import IMX command (it’s on the Import panel of the Home tab of the ribbon or type IMX_IMPORT at the command line). Simply browse to the .imx file and bring it in. Because both the .imx file and your drawing have coordinate systems assigned, the DEM file comes in at the correct location and at the correct elevation. You may want to change the name of the surface as well as the style but, you now have a beautiful DEM file in your drawing and you didn’t ever have to know what coordinate system it was using!

Import the .imx file into Civil 3D

And if anyone is wondering, the DEM file I used while creating this blog post created a surface in Civil 3D with almost 4 million points.

Surface Properties