Error adding large DEM

[cb0010]

Hi, I have been trying to add a county wide 3m dem into C3D 2012 with no success.  My goal is to be able to open a drawing, zoom into a small section of the county and instantly have an accurate surface to look at.  I realize this is an extrememly large file with over 450 million points but I was hoping that if I set the surface to "no display" then created a boundary around the work area before turning the surface on it might work.  However, I can't even get the dem to load without crashing the computer.  I have a brand new high end laptop with plenty of ram so I don't think that is the issue.  I've also tried adding a data clip boundary to the surface then adding the dem.  This worked but was extremely slow loading defeating the purpose.  Is there another method anyone has used for adding a dem as large as this to a surface?  Thanks.

[Neilw_05]

There are several posts about problems loading DEMs. C3D just does not handle large data sets well, even with lots of RAM. The only workaround so far is to use data clip boundaries to reduce the coverage area or use lower resolution datasets or a combination of the two.

A search for the topic DEM should get you several usefull hits.

You can also display DEM's using Map which should be easier to load,  but that won't give you a functional Civil 3D surface.

[antoniovinci]

Try to handle that huge file as a true 'point cloud', not as a surface, sir.

Another option is to crop the Dem to a smaller region, by means of a Gis opensource.

[BrianHailey]

Or, you could use Autodesk Infrastructure Modeler to help you get just the piece of the surface you want. I think this fits the bill of what you want. Load the entire county, open the model, and export out just the part you are working on for this particular project.

I did a quick video (it's just over 6 minutes) showing the process. You can see it HERE.

[cb0010]

Thanks for the quick responses.  I'll go in order here..first, regarding the data clip boundaries...when you add a dem to a surface with a data clip boundary already added, is the dem being clipped first and then brought in or is it being brought completely in and then clipped?  I'm guessing it's the latter since it takes so long to load but am just curious.  Either way it seems faster to clip the dem with another program first.

Second response..I do have the raw lidar data which I processed to a bare earth .las and then brought into C3D as a point cloud.  This worked but the file is still too large even after reducing the number of points to the absolute minimum necessary to get an accurate surface.  Are you saying that I can process the dem itself as a point cloud?  If so by what means? I am able to clip and export the dem using gis software but was hoping to remove that step as it can be cumbersome when you are looking at many different sites in a day. 

Third response.  I really appreciate the video and although that looks like a great method (and a cool program) I don't think our orginization is going to spring for that any time soon. 

Thanks again for the replies, I'm going to keep trying and if I come up with a good solution I'll be sure to post it. 

[Neilw_05]

Data Clip boundaries limit the data BEFORE it is processed, so they are a good way to reduce the amount of data imported into the surface.

[BrianHailey]

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@cb0010 wrote:

Third response.  I really appreciate the video and although that looks like a great method (and a cool program) I don't think our orginization is going to spring for that any time soon.  

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If your Civil 3D is on subscription, you will have it soon unless you specifically say you don't want it: C3D Migration