large points file - how to cut out a rectangle

I have a large (200mb) points file, from which I need to import just a specific area into acad. Can this be done from the command line, or do I need a separate, or add-in program?

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Just curious - what does the 200Mb file represent? What type of work do you do? I am told Terramodel handles large numbers of points much better than ACAD but I have yet to see this theory proven.
Happy Trails To You

The file represents an area of sand dunes. I'm looking to cut out a rectangular area and use acad to generate contours and experiment with surface modeling/lighting. I just looked up Terramodel - too pricey, I think.

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What Trimble does not tell you on their web site is that you buy the FDM version of Terramodel from just about any Trimble dealer for $100 or so - I think the list is C$375 in Toronto. For another $100 you can register it with Trimble for support by phone & email for a year, so it's not as expensive as they'd have you believe.
The Field Data Module is the one they give away with the Sitevision automatic grading systems, and you can do just about any dtm preparation and points editing with it.
If you want to draw smoothened contours, or design roads or piping systems, or manage a drawing/plotting system, or some of that additional specialized stuff, then you're into the bigbucks versions.
If you are capable of doing some programming for simple processing of ascii files why not process your file and throw away anything that is outside a given rectangle, writing the ones inside to a new file, then process that new file?
Happy Trails To You

HiHo; Import the file into Excel or some data management program. sort by X then Y. Import the XY range you are interested in into AutoCad.
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Can XL handle files this large?
Happy Trails To You

Thanks for that. File opens OK in Excel - need to practice with sorting and save formats.

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Hey John,
I was looking yesterday for a text editor that could handle large files so I could edit Autocad DXF files, and got a few good suggestions.
I dl'd and tried one on the largish dxf I had, then remembered fooling around with that zipped DAT file you sent me several weeks ago.
After loading it into the editor (EDITPAD.PRO) I was trying out, I discovered that it after deleting the fuzz off the front of the file, it actually has 606,759 points in it - not the 64k I/we thought before.
I would guess that XL screwed up on that large a file and threw away the extra (most) points.
I then imported the file into Terramodel and I'm looking now at a (very) slowly revolving rendering of the whole darn thing. When it finally gets through the stack of whatever the heck I asked it to do, I'll render a smaller section of it and see what it actually looks like up close.
I'm surprised that Tm didn't even hiccup over almost 2/3 million points!
- Tom
Happy Trails To You