Buildings' Elevation from CAD file

[anthonykitchin]

Hi all,

I'm kind of new to CAD and I was wondering if in ArcMap it's possible to build 3D model from a CAD file (dwg or dxf). I attach an image with the kind of data I have. The numbers on buildings and streets (annotations?) are the heights of each these features (at sea level).
Does anybody know if it's possible to build a 3D model with this data? I have seen something similar done interpolating data on shapefiles but I don't know if that applies to CAD files.
Thanks in advance,

JF

[KarenHodge]

The short answer is yes, it can be done.  You have a couple of tasks first.  You've seen how you interpolate data from a shapefile, so I'm guessing you understand that if you have some feature, like a polygon, that represents a building and one of the fields is the building's height, you can represent it as an extruded 3d shape.

The trick is how do you get that polygon feature from the CAD file and get the piece of text in the drawing to be a numeric field attached to that polygon. 

Your answer will be in Geoprocessing.  Which geoprocessing tools you use will depend on your drawing.  CAD drawings are organized in many different ways.  You can add the CAD drawing dataset into ArcMap and explore it to see how best to work with it.
I'd start by converting the file to a geodatabase using a tool like Cad to Geodatabase.

You have lots of linework in this CAD drawing--some are your building outlines and some aren't.  You'll need to isolate out JUST the building lines.  You may be able to do that by creating a feature layer with a query of "Layer=<some value>", where <some value> is the name of the CAD layer that contains the building outlines.  (This assumes, of course, that the building outlines are on a separate CAD layer.)

The linework that represents the building outlines may or may not be drawn as closed polygons in the CAD file.  They probably aren't.  If not, you may want to use the tool Feature to Polygon to create polygon features.   Additional GP tools will allow to you join or extract the text to attach as an attribute to the features.

There are numerous help topics on how to work with CAD data in ArcGIS...explore a bit and ask here if you get stuck.

Hi all,

I'm kind of new to CAD and I was wondering if in ArcMap it's possible to build 3D model from a CAD file (dwg or dxf). I attach an image with the kind of data I have. The numbers on buildings and streets (annotations?) are the heights of each these features (at sea level).
Does anybody know if it's possible to build a 3D model with this data? I have seen something similar done interpolating data on shapefiles but I don't know if that applies to CAD files.
Thanks in advance,

JF

[CoreyVan_Es]

Hello,

I have a similar problem, but with point elevation data. I have used the CAD to Geodatabase tool, but the elevations are stored as text in the annotation file and not as numeric data in the point layer.  Does anyone know how to assign these elevations to their corresponding points in the point layer?

Thanks,
Corey

[anthonykitchin]

Hello,

I have a similar problem, but with point elevation data. I have used the CAD to Geodatabase tool, but the elevations are stored as text in the annotation file and not as numeric data in the point layer.  Does anyone know how to assign these elevations to their corresponding points in the point layer?

Thanks,
Corey

I think my CADs have the same structure. Elevation points are stored as text annotations in one of the layers. What I did to transform them into points was to use the "Feature to point" tool. There, you input the layer containing the annotations and ArcGIS will create a point shapefile. Annotations (elevation points) will become a field in the attribute table of the new point shapefile.
Hope it works for you...

[CoreyVan_Es]

Thanks for your reply. The Feature to Point tool works well, the only thing is the locations of the annotation are not where the actual point data are, meaning the measurements are off by the distance between the original point file and the newly created point file (from the annotation layer). Unfortunately the offset distances are not uniform throughout the dataset. I tried a spatial join to see if I could get the elevations to apply to the original point data file; this works for about 75% of the data (as observed using the frequency analysis tool). So I'm close.....if anyone has any further ideas please let me know!