## AutoCAD Civil 3D General Discussion

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Message 11 of 26 (1,536 Views)

# Re: Serious Coordinate Conversion Issue

02-08-2012 12:33 PM in reply to: kkuecker-traffic

Usually when drawings, images, pdf's, etc. are attached, and they shift, it has to do with being to far away from the origin point, which is 0,0,0.  This is what they call a Large Coordinate Issue.

The accuracy drops the further away from the origin objects are drawn.  They can easily be off by inches or feet when far away.  The attachment origin may still be near 0,0, but the attachment objects are far away, and it shifts the file.  Large Coordinate issues come into play when objects are past 5000 units from origin.  If the drawing units are in inches, and objects are beyond 416 feet, they are beyond the limits.  The ending result is the attachment being off.

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Message 12 of 26 (1,532 Views)

# Re: Serious Coordinate Conversion Issue

02-08-2012 12:40 PM in reply to: kkuecker-traffic

YAYAYAYAYAYA....Live Action X

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Message 13 of 26 (1,531 Views)

# Re: Serious Coordinate Conversion Issue

02-08-2012 12:45 PM in reply to: TRogers

Do you realize that is a totally unaccaptable reponse????

We bought this software thinking that it is capable of doing Transportation design.  Our distance from the 0,0 mark is always going to be a great distance.

the point we were questioning was at X= 244559.68, Y=570888.28.  The linear distance from 0,0 is then 621,065.91 ft or 117.63 miles from 0,0.

The difference between one International Foot equals 0.999998 U.S. Survey Feet exactly.  So the 621,065.91*.000002 equals a 1.24 foot shift.

If we import MicroStation files into AutoCAD we have a 1.24 shift if we do not use the MAPIMPORT command.  1.24 feet is A HUGE DIFFERENCE!!!!!

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Message 14 of 26 (1,518 Views)

# Re: Serious Coordinate Conversion Issue

02-08-2012 12:56 PM in reply to: kkuecker-traffic

This issue doesn't have anything to do with International feet and US Survey foot.  It has to do with the Large Coordinate Issue.  There is a good article on this at the link below....

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Message 15 of 26 (1,508 Views)

# Re: Serious Coordinate Conversion Issue

02-08-2012 01:24 PM in reply to: TRogers

Actually it is both a conversion and large coordinate issue.  That 0.000002 difference between US Survey and International over millions of "feet" equates to 1 or 2 (or even 3) feet off. We have had imports off by as much as 2.75'

Bottom line, MAPIMPORT is the only way to insure that it is doing an accurate conversion/import.  We have seen this mostly on DGN imports, but also on our Trimble GPS imports that we forget to set to US Survey Foot.

That is a good article because it does address issues like hatches and certain other commands.  But in the office here we have proven (unfortunately, time and again) that it is a conversion issue when it comes to points.  .0002% over millions of feet gets big pretty darn quick.

My 2 cents, for what it's worth.

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Message 16 of 26 (1,497 Views)

# Re: Serious Coordinate Conversion Issue

02-08-2012 02:06 PM in reply to: kkuecker-traffic

i  have never experience that problem. but its seems like to me is that the dgn file is the problem. the micorstation file has be convert to the dwg format correctly before it will work correctly. this is something i have done many times without any problems. generaly microstations works in international xy system and when you are in civil 3d you can actually set the state plane system you are using and believe it or not there is a difference. i would think the problem is in the setup of the dgn file i bet its set to internation foot and not u.s. foot. i did this very same thing this morning and and worked perfectly.

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Message 17 of 26 (1,484 Views)

# Re: Serious Coordinate Conversion Issue

02-08-2012 04:26 PM in reply to: jmatte2004

I, too, feel this is a problem in the DGN setup.  Like I said, we can have the Corps use Microstation to create DWG files for us (no C3D involved), and we'll get inconsistent results.  It's always seemed like an error somewhere on the Microstation side.  I'm just mightily confused as to why we notice the problem once they convert the files to DWG, while they don't seem to notice the problem while working in the DGNs.

Sinc
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Message 18 of 26 (1,472 Views)

# Re: Serious Coordinate Conversion Issue

02-09-2012 07:30 AM in reply to: TRogers

The problem is on both MicroStation and AutoCAD.

We found that MicroStation has a setting in the export process for either feet or survey feet.  If survey feet is not selected in the settings of the seed file, the export will be shifted by .000002.

However, AutoCAD has a setting hidden away for the reference attach of DGN's that automatically puts it in International feet.

Unless you use MAPIMPORT for a straight DGN

OR

a correct seed file to export a DWG to DGN

IT WILL NOT ATTACH PROPERLY.

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Message 19 of 26 (1,466 Views)

# Re: Serious Coordinate Conversion Issue

02-09-2012 07:49 AM in reply to: kkuecker-traffic

That's good to know, being that I am not a Bentley user.

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Message 20 of 26 (1,455 Views)

# Re: Serious Coordinate Conversion Issue

02-09-2012 10:02 AM in reply to: kkuecker-traffic

One thing is the problem that any command that is vanilla AutoCAD based will not deal with Survey Feet. Only Map and Civil know the difference. You see this in you have your insert units set and try to Insert a drawing done in meters in to a drawing that is in Survey Feet. The insert command will convert Meters to International Feet only.

It may be time for Autodesk to think of issuing a special build of AutoCAD for Civil 3D. There are Map 3D commands that are disabled in Civil 3D because they will muck up the units. AutoCAD built for Civil 3D should be able to handle Survey Feet!

Allen

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