Civil 3D - drawings switch from US feet to International feet

Here are a few things that I would verify:

1. Your Export LandXML settings.?ÿ Toolspace>Settings Tab>Right-click drawing>Edit LandXML Settings>Data Settings>Imperial Units.
2. Your drawing settings through your Toolspace.?ÿ I'm sure you know where that is and that you've set this.?ÿ By the way, make sure that Set AutoCAD variables to match is checked on.
3. I can't see this causing a problem, but you can also check your insertion scale units. Units>Insertion scale>US Survey Foot.?ÿ?ÿIf you did the last part of (2) then this should be set correctly, but it may not have been set by default.

I think (1) may be your issue, but let us know if any of these help.

For (1) above, I forgot to mention that when you get the the Edit LandXML Settings box, you will have both an Import and an Export tab.?ÿ Make sure you are looking at the Export tab.

Yes, all of those are right.?ÿ It's (2) that's the important one to have right and that's the one that seems to inexplicably be changing on its own.?ÿ We'll have a drawing that it's set to US Survey Feet and do a few exports from then save and close.?ÿ Then the next time we get into it we think everything is good because we've already successfully exported things from it but then we get the call from the field that the points don't match the lines.?ÿ Go back in and check (2) and it's changed to International Feet.?ÿ We're keeping a close eye on it and checking before each export but what it's doing isn't supposed to happen.?ÿ

On the staking jobs we're getting CAD files from all the various design firms.?ÿ Many (if not most) of their drawings are set to I.F. but that shouldn't be an issue the way we set things up.?ÿ We have a staking template that we XREF all the various base files into and it has all the settings the way we want them including the definition of the metric-imperial conversion.?ÿ Could an XREF drawing setting be matriculating up the hierarchy and changing things in the top level drawing??ÿ I've never seen that happen.?ÿ?ÿ

This discussion will be moot in a few years, as the Feds intend to deprecate the U.S. Survey Foot at the end of 2022.?ÿ After that all official U.S. measurements will either be in meters or feet (the latter being the successor term to "international feet").?ÿ My understanding is that all states currently using the U.S. Survey Foot in their SPC definitions will also make the change.

@jim-frame

The vendors will need to continue supporting US Feet for legacy coordinate systems and data.

Many states are on board with the change but there are 57 jurisdictions and most need to make legislative changes. I would not make a bet that all will succeed.. 

Posted by: @cameron-watson-pls

Yes, all of those are right.?ÿ It's (2) that's the important one to have right and that's the one that seems to inexplicably be changing on its own.?ÿ We'll have a drawing that it's set to US Survey Feet and do a few exports from then save and close.?ÿ Then the next time we get into it we think everything is good because we've already successfully exported things from it but then we get the call from the field that the points don't match the lines.?ÿ Go back in and check (2) and it's changed to International Feet.?ÿ We're keeping a close eye on it and checking before each export but what it's doing isn't supposed to happen.?ÿ

On the staking jobs we're getting CAD files from all the various design firms.?ÿ Many (if not most) of their drawings are set to I.F. but that shouldn't be an issue the way we set things up.?ÿ We have a staking template that we XREF all the various base files into and it has all the settings the way we want them including the definition of the metric-imperial conversion.?ÿ Could an XREF drawing setting be matriculating up the hierarchy and changing things in the top level drawing??ÿ I've never seen that happen.?ÿ?ÿ

My first reading I was thinking you were talking about (2), but I couldn't make myself believe that because I've never seen it happen.?ÿ I've done a little research, and while I see one thread where a couple of people (Messages 9, 11, & 14) describe the same thing you do, but there is no resolution as their issue was not the same as the OP.?ÿ Do you set a zone also??ÿ For me, once I select state plane coordinates, the option to change between Imperial and U.S. Survey Foot becomes grayed out.?ÿ Is this the same for you, yet gets changed anyway??ÿ Is this only happening in one project, the occasional project, or all projects?

As to your second paragraph, I've never seen that happen either, and I don't think that would be the case.?ÿ That doesn't mean it's not happening that way.

@blitzkriegbob

I don't ever set a coordinate system in C3D on our staking jobs so that's not it.  It doesn't seem to be happening on all jobs and appears to be random which ones it happens to.  Sometimes it will stick through several opens sometimes not.  It's the damnedest thing and more than a little spooky.  Maybe my server is haunted and it will all clear up in a few weeks...

Posted by: @thebionicman

Many states are on board with the change but there are 57 jurisdictions and most need to make legislative changes. I would not make a bet that all will succeed..?ÿ

I was in a meeting yesterday in which our NGS advisor said that the 40 states that still have the survey foot on the books have all committed to making the change.

@jim-frame

The initial resistance did collapse fairly quick. The issue now is getting the legislation done. Even good proposals with broad support face a long and winding road....

@jim-frame

There's a lot of curb and pipe to be staked between now and the end of 2022...