Using the 3d in AutoCAD Map 3d

3 February , 2008

Hi all – today’s post is all about the 3d!

Well if you are anything like me you have called the software ‘Map 3d’ many times but have all to often ignored the 3d part! When speaking to customers I often hear “We only work in 2d” or “3d would be nice but it takes to long to get results” – Well in this post I want to show you thats not always true!

AutoCAD Map 3d has a great, fast, easy way to produce a 3d visualisation. Although the product has no capabilities for creating surfaces from X,Y,Z data – you will require AutoCAD Civil 3d for that – you are able to connect to existing 3d surfaces that have been created externally to AutoCAD Map. These include DEM (Digital Elevation Model) files, ESRI Grid files (asc Grid), or Digital Terrain Elevation Data (DTED).

Here in the UK for example there are a number of sources I can purchase pre-existing 3d surface data that will read directly into AutoCAD Map. One such source is from a comapny called eMapSite that offer a range of digital geospatial data, including 3d surfaces – The data in this example was kindly provided by them.

To access the data within AutoCAD Map you use the Feature Data Objects (FDO) technology, which connects directly to the file and displays it within the DWG. Once you have connected to the raster-based surface, you can create contour maps to help you analyze 3D terrain. You can use raster-based theming to analyze elevation, slope, and aspect, and drape other map data over the surface. You can also view the data in 3D with walk-through and fly-through options, creating compelling visualisations.

Here are 5 quick steps to produce a 3d visualisation and perform some flooding analysis.

Step 1 – Connecting to the 3d surface file

Open the ‘Data Connect’ menu from the ‘Display Manager’ and select the ‘Add Raster Image or Surface Connection’. Navigate and select the surface file you wish to add (in my case its a .asc). Then tick the box and hit ‘Add to Map’. This will add your 3d surface connection to your DWG in the same way you would add any other raster file.

Your surface will now appear in Model space and the layer will appear on the Display Manager.

Step 2 – Adding additional data to drape onto the surface

To add an aerial photo to drape onto the surface, open the Data Connect menu again and select the ‘Add Raster Image or Surface Connection’. But this time add an aerial photograph or other relevant raster file that you have. 

When you view this data in 3d the raster image will drape automatically onto the 3d surface. It is also possible to use the FDO access tools to connect to vector data which will then automatically drape on the surface also.

Tip – When dealing with DWG CAD entities, these will NOT drape on the surface so you need to ensure the entities are given the correct elevation to appear in the correct place in the 3d world.

Step 3 – Adding the flood surface

To enable me to produce some flood analysis I need to create an object to represent the flood. To do this you can add a simple polygon CAD entity.

Draw a polygon around the surface – You may wish to snap your polygon to the edge of the surface to make the visualisation clearer. Once completed select the properties of the polygon and change the colour fill setting to Blue.

Step 4 – Visualising the data in 3d

Now its time to view the data in 3d.

Select the ‘3d Mode’ button underneath the Model space tab.

Tip – It’s important you use this button to switch to 3d mode as it applies the stylisation settings required.

The data is now viewable in 3d and you can use the 3d navigation tools to move around.

Step 5 – Adding the Flood height

Finally you can specify the height of the flood you want to analyse. 

Select the blue polygon underneath the 3d model, right mouse click and select ‘Properties’. In the properties editor, underneath the ‘Misc’ section, enter your flood height into the ‘Elevation’ field.

Before Elevation Change

After Elevation Change

This will raise the polygon on the Z axis to the relevant height and cut through the model.

Hopefully you will all agree that once you have the right 3d surface data, this is quick, easy and a great starting point for creating compelling visualisations and fly-throughs.

There are a number of other things you can do with the surface, including style it based on Height, Slope and Aspect; plus you can produce a contours dataset from the surface. I have written a short ‘How 2’ guide on how to insert and style 3d surfaces in AutoCAD Map 3d, which . If you are interested please drop me an email –

See you next time.  

It all becomes transparent…..

6 January , 2008

Happy New Year!!! So here is my first post of 2008 – I did intend to post a few times over the festive period but got caught up in mince pies and sherry……But better late than never.

When AutoCAD Map 2007 was released with its new FDO (Feature Data Object) engine I found the transparency functionality and thought – ‘excellent see-through data!’. There was a catch however, although it’s great for polygons, I have never been able to make raster data transparent – until now!!

Through some useful posts from the community on the AutoCAD Map discussion forum; and through some trial error, I can now make my raster images transparent. This is how to do it……..

Step 1 – Add the raster image to the DWG through FDO

Open the ‘Data Connect’ menu found on the ‘Display Manager’. Once in the editor, select ‘Add Raster Image or Surface Connection’, navigate to the file you wish to connect to and then tick the box and hit ‘Add to Map’.This will add your raster image connection to your DWG.

Before Insertion


After insertion

As you can see from the screen captures above, the image displays in the correct location as AutoCAD Map understands its associated ‘World File’. However it has been placed in front of the stadium design CAD data, hiding it.

Using the Display Manager I am able to manage the draw order of my data in Model Space and could force the image behind the CAD data. In future posts I will explain the tips for doing this. In this example however I want to make the image transparent.

Step 2 – Save a ‘Layer file’ for the image

A Layer file is an XML based file that you can export from AutoCAD Map for any FDO connection you have made in the Display Manager. Within the file it will save all the styling information and it also records the location of the data source e.g. Location on disk of the Raster Image file. Once the file has been created you can add saved Layer files into any AutoCAD Map DWG to re-use them – making it very easy to connect and style the data.

To create a Layer file for the raster image that has been connected simply right mouse click the layer on the Display Manager and select ‘Save Layer’

It will prompt you for a name and location to save the Layer file. 

Step 3 – Edit the Layer file to enable the transparency.

To make the image transparent you need to add a extra line to the Layer file. In Windows Explorer, navigate to the Layer file that has just been saved and open it in Notepad.

This is the data contained within a Layer file.

To add the transparency setting, find the line that defines the ‘FeatureName’. Its usually about 22 lines down in the file. 

It looks like this: 

FeatureName: <FeatureName>rasters:MyRasterImage</FeatureName>

Underneath this section on a new line add the following…..


0.5 being the degree of transparency – 0.1 is very transparent, 0.9 is not very transparent.

This is how your file should look:

Before Edit


After Edit

Once you are happy, save the notepad file.

Step 4 – Add the Layer file to AutoCAD Map DWG.

Now you have added the transparency in the Layer file you can add the Layer file to your DWG.

Turn off any other Raster Imagery in your DWG. From the Data button on the Display Manager select ‘Load Layer’ and point to your Layer file.

This will add the Raster Image to the Display Manager in the same way as doing a Data Connect would do, except this time the transparency should be activated.

You now can see the Stadium CAD data below the image.

Check back for more soon!