Trimble Business Center

Why is my data exported to dwg from TBC always shifted +/-28' to the north-east in Civil 3D. If I choose unitless in the export options, it comes in correctly lined up. It does not work when set to US Survey Feet. It has done this for years. But now I am trying to export point clouds to Civil 3D and I do not have the option to set to unitless. Same shift or more than likely scaled wrong.

-Tommy

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Thomas Tomsu
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It's more than likely your settings in Civil3d that are causing the problems.  Be sure your drawing is setup in the right coordinate system with the correct units.  Not sure why you would want point clouds in Civil3d as TBC handles them significantly better.

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Mike Hathaway
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My client wants the point clouds in Civil 3D (not me). We have set the coordinate system correctly.  My dealer has heard about this too, but has no solution.

Temporarily forget about point clouds. Has anyone else seen this shift of linework when exporting in US Survey Feet from TBC to Civil 3D? I agree that it is a Civil 3D problem with the translation. I discovered problem many years ago. So my solution is to always set dwg export to unitless and it works without any issues. This option is not available with point cloud exports.​

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Thomas Tomsu
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Original Message:
Sent: 03-08-2022 08:12
From: Mike Hathaway
Subject: Civil 3D xref of TBC data shifted or maybe scaled

It's more than likely your settings in Civil3d that are causing the problems.  Be sure your drawing is setup in the right coordinate system with the correct units.  Not sure why you would want point clouds in Civil3d as TBC handles them significantly better.

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Mike Hathaway
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This is somewhat of a wild guess, it may not be helpful. I know next to nothing about TBC but have a little experience with AutoCAD.

You probably know that AutoCAD / Civil 3D has numerous places where units can be set. Have you checked all of these places? I doubt that this is the problem anyways.

• aecceditdrawingsettings (this is probably one you've addressed already)
• units
• -dwgunits (also try responding to the two questions with 'N' for No)
• insunits

Alternatively, you might look for some other format that Civil 3D can import, perhaps something closer to raw text.

Mike Hathaway: How could settings in Civil 3D be the problem while TBC is writing the file? Unless TBC uses a dwg file as a template for establishing unit settings before making the export. Even if we change units in Civil 3D dwg file, a translation should not occur (which means this could not correct the issue). At least that's been my experience.

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Paul Lohr
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Original Message:
Sent: 03-09-2022 06:26
From: Thomas Tomsu
Subject: Civil 3D xref of TBC data shifted or maybe scaled

My client wants the point clouds in Civil 3D (not me). We have set the coordinate system correctly.  My dealer has heard about this too, but has no solution.

Temporarily forget about point clouds. Has anyone else seen this shift of linework when exporting in US Survey Feet from TBC to Civil 3D? I agree that it is a Civil 3D problem with the translation. I discovered problem many years ago. So my solution is to always set dwg export to unitless and it works without any issues. This option is not available with point cloud exports.​

------------------------------
Thomas Tomsu
------------------------------


Original Message:
Sent: 03-08-2022 08:12
From: Mike Hathaway
Subject: Civil 3D xref of TBC data shifted or maybe scaled

It's more than likely your settings in Civil3d that are causing the problems.  Be sure your drawing is setup in the right coordinate system with the correct units.  Not sure why you would want point clouds in Civil3d as TBC handles them significantly better.

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Mike Hathaway

Since you are exporting RCP point cloud from TBC, there is a grid/ground setting in point cloud export. If your project is scaled to ground, the export setting should be grid, so it doesn't get scs,Ed again

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Robert Hoy
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Original Message:
Sent: 03-09-2022 06:26
From: Thomas Tomsu
Subject: Civil 3D xref of TBC data shifted or maybe scaled

My client wants the point clouds in Civil 3D (not me). We have set the coordinate system correctly.  My dealer has heard about this too, but has no solution.

Temporarily forget about point clouds. Has anyone else seen this shift of linework when exporting in US Survey Feet from TBC to Civil 3D? I agree that it is a Civil 3D problem with the translation. I discovered problem many years ago. So my solution is to always set dwg export to unitless and it works without any issues. This option is not available with point cloud exports.​

------------------------------
Thomas Tomsu
------------------------------


Original Message:
Sent: 03-08-2022 08:12
From: Mike Hathaway
Subject: Civil 3D xref of TBC data shifted or maybe scaled

It's more than likely your settings in Civil3d that are causing the problems.  Be sure your drawing is setup in the right coordinate system with the correct units.  Not sure why you would want point clouds in Civil3d as TBC handles them significantly better.

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Mike Hathaway

Here are a few relevant facts about this situation:

1. Civil 3D units and AutoCAD units are not the same, can be set differently, and do not work the same way.
2. Civil 3D units are only honored by Civil 3D commands. Everything else is handled by AutoCAD using its unit settings.

AutoCAD 2016 and prior had one imperial units option: "Feet". In 2017, they introduced a new unit: "US Survey Feet". The way they went about implementing this new unit was, in my opinion, absolutely unforgiveable. Starting in 2017 the default handling of "Feet" units was set to International Feet, even when upgrading an older drawing that had no distinction between international and US Survey Feet. The "conversion" was applied transparently and without warning to the end user. It's reasonable to assume that many people who used 2016 would've set their default units to "Feet" in their primary template drawings, and those settings would've been inherited during future upgrades. However, when you set your C3D settings in 2017+ with the "Set AutoCAD variable to match" box checked, you're now telling AutoCAD to use US Survey Feet instead of "Feet" (assuming you're in the US and use US Survey Feet). Older drawings that lacked the distinction between these two units would now be assumed to represent international feet and there was no option to circumvent this. Essentially, AutoCAD decided starting in 2017 that every drawing you ever created with "Feet" units must have been International Feet only.

Here's an example of how to recreate this issue:
Create a drawing in Civil 3D 2016 and set the C3D Drawing Settings to US Survey Feet, with the "Set AutoCAD variables to match" box checked (like below):
(Check your UNITS afterwards, you'll see "Insertion scale" units = "Feet")

Now, do the exact same thing in Civil 3D 2017+ and check your UNITS, now "Insertion scale" units = US Survey Feet. You can see where this is about to go wrong!
Next, XREF your 2016 drawing into the 2017+ drawing. Job done! You've now got messed up XREFs, and AutoCAD didn't warn you or make any fuss about the fact that it's doing something so clearly severe despite there being no unambiguous call for it to happen.

This probably didn't get picked up by those who use local / assumed coordinates, but for those of us operating in State Plane Coordinates this amounts to shifts of 10 feet or more. Enough to destroy your hard work, but not enough to immediately go undetected.

Because of the fact that AutoCAD is programmed to handle unit conversions automatically and silently, we (as a firm) have opted to abandon the use of defined units in all of our drawings moving forward. Every new drawing is set to "Unitless" and we handle the scaling ourselves in the extremely rare case when it is necessary. This makes it possible to XREF older content into our current drawings without having to remember to go back and fix it later.

To "detect" and reverse this issue in progress, here's what you do:

1. Run UNITS and set the Length type to Decimal and Precision as high as it will go.
2. Open the properties for your reference.
3. For XREFs, look under "Misc" (might be elsewhere for different types of references". You're looking for "Unit factor".
4. If it isn't 1.000000000000000 you're being scaled. Likely it'll either say 0.999998 or 1.000002. That's the scale factor for international/US survey feet.
   
5. Select your XREF and run the SCALE command. Base point should be whatever your reference's base point is.
6. Type in the inverse of the "Unit factor" for the scale factor
7. Unit factor will remain the same but you're countering that with a X/Y scale factor.
   

Alternatively, if you're married to the use of the defined units in AutoCAD, you can temporarily change your Insertion scale units to Unitless immediately prior to running the XREF or import function, and then revert it back afterwards. The process is not retroactive or real time - it only happens during the actual XREF/import process based on the unit settings in effect at that moment.

I don't know what solution is appropriate for your client, but that's the nature of the problem and it's what you have to be aware of when the decision is made to use defined units in AutoCAD.

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Scott Roberts
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Thank you Scott, that worked perfectly. I ran the "UNITS" command in Civil 3D and set to import to US Feet. Now everything drops in where it supposed to. Now I just need to get my clients to change their template with this.

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Thomas Tomsu
------------------------------

Original Message:
Sent: 03-09-2022 09:41
From: Scott Roberts
Subject: Civil 3D xref of TBC data shifted or maybe scaled

Here are a few relevant facts about this situation:

1. Civil 3D units and AutoCAD units are not the same, can be set differently, and do not work the same way.
2. Civil 3D units are only honored by Civil 3D commands. Everything else is handled by AutoCAD using its unit settings.

AutoCAD 2016 and prior had one imperial units option: "Feet". In 2017, they introduced a new unit: "US Survey Feet". The way they went about implementing this new unit was, in my opinion, absolutely unforgiveable. Starting in 2017 the default handling of "Feet" units was set to International Feet, even when upgrading an older drawing that had no distinction between international and US Survey Feet. The "conversion" was applied transparently and without warning to the end user. It's reasonable to assume that many people who used 2016 would've set their default units to "Feet" in their primary template drawings, and those settings would've been inherited during future upgrades. However, when you set your C3D settings in 2017+ with the "Set AutoCAD variable to match" box checked, you're now telling AutoCAD to use US Survey Feet instead of "Feet" (assuming you're in the US and use US Survey Feet). Older drawings that lacked the distinction between these two units would now be assumed to represent international feet and there was no option to circumvent this. Essentially, AutoCAD decided starting in 2017 that every drawing you ever created with "Feet" units must have been International Feet only.

Here's an example of how to recreate this issue:
Create a drawing in Civil 3D 2016 and set the C3D Drawing Settings to US Survey Feet, with the "Set AutoCAD variables to match" box checked (like below):
(Check your UNITS afterwards, you'll see "Insertion scale" units = "Feet")

Now, do the exact same thing in Civil 3D 2017+ and check your UNITS, now "Insertion scale" units = US Survey Feet. You can see where this is about to go wrong!
Next, XREF your 2016 drawing into the 2017+ drawing. Job done! You've now got messed up XREFs, and AutoCAD didn't warn you or make any fuss about the fact that it's doing something so clearly severe despite there being no unambiguous call for it to happen.

This probably didn't get picked up by those who use local / assumed coordinates, but for those of us operating in State Plane Coordinates this amounts to shifts of 10 feet or more. Enough to destroy your hard work, but not enough to immediately go undetected.

Because of the fact that AutoCAD is programmed to handle unit conversions automatically and silently, we (as a firm) have opted to abandon the use of defined units in all of our drawings moving forward. Every new drawing is set to "Unitless" and we handle the scaling ourselves in the extremely rare case when it is necessary. This makes it possible to XREF older content into our current drawings without having to remember to go back and fix it later.

To "detect" and reverse this issue in progress, here's what you do:

1. Run UNITS and set the Length type to Decimal and Precision as high as it will go.
2. Open the properties for your reference.
3. For XREFs, look under "Misc" (might be elsewhere for different types of references". You're looking for "Unit factor".
4. If it isn't 1.000000000000000 you're being scaled. Likely it'll either say 0.999998 or 1.000002. That's the scale factor for international/US survey feet.
   
5. Select your XREF and run the SCALE command. Base point should be whatever your reference's base point is.
6. Type in the inverse of the "Unit factor" for the scale factor
7. Unit factor will remain the same but you're countering that with a X/Y scale factor.
   

Alternatively, if you're married to the use of the defined units in AutoCAD, you can temporarily change your Insertion scale units to Unitless immediately prior to running the XREF or import function, and then revert it back afterwards. The process is not retroactive or real time - it only happens during the actual XREF/import process based on the unit settings in effect at that moment.

I don't know what solution is appropriate for your client, but that's the nature of the problem and it's what you have to be aware of when the decision is made to use defined units in AutoCAD.

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Scott Roberts
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