Building Surfaces

I am using AutoCAD Civil 3D Land Desktop Companion 2008...

I am trying to build a surface from DEM (Digital Elevation Maps) and am running into a HUGE problem. I need to create a surface file that covers about 6 DEM files (Mid south area of alberta canada) and it will go along processing/pre-processing for a while then hit a snag.

It errors and kicks me out of AutoCAD as soon as it hits the "adding point data"

The error is as follows:

FATAL ERROR: Unhandled e06d7363h Exception at 7c812aebh

Anyone able to help me figure out what is going wrong or how to fix it.

Thanks

I have been looking for an answer on autodesk site but can not find one that directly relates to my problem

i dont know how beefy your computer is but mine does that/is doing that as we speek. I dont have enough memory so it fatals out when it cant handle anymore....can you create two different drawings, each having half of the surfaces you need, then xref them into the production drawing?

that may not be your issue but it sounds similar to my situation

Sounds like it could be the issue... I was hoping it wasn't though

If you xref the drawing it it will bring the surface data with it? I am trying to learn these maps still so forgive my not knowing.

Well I got further then I ever have by turning off the Autodesk help bar at the top of my CAD. My IT guy did it for me so I can't tell you how to do it just yet but if you want to give it a try I will find out what settings he changed int he registry.

Does your project area encompass the whole area of the 6 dem's?

And when does it hit the snag? After adding the first dem? The second? Third?... Or are you trying to add them all at once (not sure it lets you do that)?

I am adding all the DEM files at once since I have to build it all at once.

It get's to the point where it says it is adding the points and then crashes. I think this time it is truely a memory problem. I am going to try to shrink the amount I need since the route I need is probably not taking all the DEM files but still I would like to be able to create a surface of any size without problems.

this is the newest error code I get

Fatal Error: Unhandled Access Violation Writing 0x0000 Exception at 10ccf2ffh

Yeah I'm thinking it's a memory issue. I've never tried to use more than one dem and even that strains my system a little bit.

You might attempt to give your surface an outer boundary first to cover your project area and then add the dem. Not sure if this will work how I'm thinking it would, but worth a shot.

In '09 you can add a data boundary which is similar to an outer boundary to restrict the data outside of your project area.

Another thought might be to create a surface and add one dem to it, then export points for that surface to an xyz text point file. Do the same with the second dem, third, and so on. After you have all 6 exported to .txt files compile them all into one point file via notepad. Then use this composited point file as surface data. This may ease the burden of such a large dataset.

Another thought might be to create a surface and add one dem to it, then export points for that surface to an xyz text point file. Do the same with the second dem, third, and so on. After you have all 6 exported to .txt files compile them all into one point file via notepad. Then use this composited point file as surface data. This may ease the burden of such a large dataset.

Ok so this sounds like it could work but (and forgive my knob question)... How do you export it to text?

I know I can create one at a time but do not know how to get the txt file and even if i do is there a specific order to add these or just drop the info from one to another.

Aw bumfuggle, it won't allow you to do that without first creating actual civil 3d points. I thought it would do it based on the points of triangulation, but I guess not.

You can create points on a grid on the dem surface and then export them by right-clicking Points in toolspace, prospector tab > export > select the export format and give the file a name and location to save. This might take a little longer though. If you do it, set your grid spacing to the same spacing as the dem to place points at the triangulation points.

Yes you would just simply copy-paste the points from each respective point file into the composited point file. There are other ways to do it, but this would work.

Did you get this worked out yet?