topic Re: Acquired Coordinates in Revit don't match Autocad survey in Revit Architecture Forum

Acquired Coordinates in Revit don't match Autocad survey

Anonymous — Thu, 10 Oct 2019 19:38:07 GMT

When I click ID on a point in the Autocad survey file it shows the correct coordinates based on the Indiana State Plain system we are using. I link the file into a brand new clean Revit file then click on "Acquire Coordinates". If I do a spot coordinate for that same spot I checked in ACAD, the coordinates do not match...in fact its exactly double in both directions.

I drew a line in CAD from the origin to a point on the plan, saved and reinserted the model into Revit. When I check the coordinates initially in Revit they are correct but when I hit "Acquire coordinates" the issue arises again and the coordinates are off by double again. Why does ACAD show the correct coordinates but its wrong in Revit after using "Acquire Coordinates"? I've done shared coordinates many times and never have seen this issue.

The image attached is of the plan in Revit showing the line I drew. The blip in the upper right corner is the survey info. The lower left corner is the origin. The numbers shown in the lower left are what it should be reading in the upper right. Instead the upper right is double the numbers shown in the lower left.

Re: Acquired Coordinates in Revit don't match Autocad survey

barthbradley — Thu, 10 Oct 2019 20:52:29 GMT

Spot Coordinate using Survey Point Origin as Coordinate Origin?

...I'm looking at your screenshot and trying to figure out what you did. The workflow should be: insert the CAD into Project. Acquire Coordinates. Survey Point, if clipped, would jump to the 0,0,0 Origin of the CAD. The Project Base Point wouldn't move.

I'm also wondering how the Angle to True North was established.

Re: Acquired Coordinates in Revit don't match Autocad survey

SteveKStafford — Thu, 10 Oct 2019 20:45:49 GMT

Are you certain the units of the file are being interpreted correctly? If the settings Revit looks for are missing from the file it doesn't always "guess" correctly when set to Auto-Detect. If you know the units are Feet then select that while linking the file. I also set the project units to the same as the AutoCAD file so I can compare them correctly. For example if the Survey is Decimal then I use Decimal Feet and the sound rounding. I usually go with six decimal places but matching the survey is the goal.

If you can share the survey file it would be a lot easier to figure out.

Re: Acquired Coordinates in Revit don't match Autocad survey

Anonymous — Wed, 16 Oct 2019 13:51:55 GMT

In the CAD file I drew a line from a point on the plan to the origin, saved the file and then began the workflow you described below. Revit inserted the CAD file so that the end of that line that was at the origin in CAD is on the Survey/Project base point which is at 0,0,0. When I acquire Coordinates the value of both the Survey Point and PBP change to the value shown in the screenshot. I did not unclip either one before acquiring coordinates. The coordinates shown there would be the correct coordinates if the PBP and SP were on the actual project site but they're not. If I grab a spot coordinate from the job site its around N4625380, E5685684, almost exactly double what they should be. Angle of true north is established by acquiring coordinates.

I'm beginning to think the issue lies with the CAD file, not with Revit.

Re: Acquired Coordinates in Revit don't match Autocad survey

Anonymous — Wed, 16 Oct 2019 13:57:12 GMT

Steve, the units in Revit are set correctly to Decimal Feet just like the CAD file. I am attaching the survey file for help in your investigation.

Re: Acquired Coordinates in Revit don't match Autocad survey

barthbradley — Wed, 16 Oct 2019 15:14:52 GMT

So you are saying that the end of the line represents the 0,0,0 Origin of the DWG, and that it is originating from the Project Base Point/Survey Point of a new, default Revit Project? If so, then the Project Base Point and Survey Point/Origin would not move when you Acquire Coordinates of the DWG. Why would they? The PBP and SP/O are already sitting on the 0,0,0 Origin of the DWG (e.g. the end of the line). By Acquiring Coordinates, you've just locked the Survey Point Origin to the DWG. In other words, if you now move the DWG in the Revit Project, the Survey Point Origin will move with it. If the Survey Point Marker is Clipped, then it will move as well. The Project Base Point will not move, but its coordinates will change to reflect its position relative to the moved Survey Point (/DWG) Zero Origin.

Re: Acquired Coordinates in Revit don't match Autocad survey

Anonymous — Wed, 16 Oct 2019 15:24:34 GMT

Not sure where you are going with this. You are correct with the first half of your statement. The last part though is where you are losing me. When I acquire coordinates the SP and PBP stay where they are but their value changes to the one showed in the original screenshot. If I move the CAD plan to where the SP is and leave the SP clipped I get a message saying that the shared sites have been modified but not saved back...If I unclip the SP and move the CAD plan the SP moves with it and the PBP now shows the coordinates as double what they should be. The PBP is now on the site but its coordinates are completely wrong.

Re: Acquired Coordinates in Revit don't match Autocad survey

barthbradley — Wed, 16 Oct 2019 16:33:10 GMT

Re: Acquired Coordinates in Revit don't match Autocad survey

Anonymous — Wed, 16 Oct 2019 16:46:29 GMT

No, thats not the problem. Inserting that way makes the northing and easting dimensions be around 2 billion feet. They should be 2 million and change. Also pulled a distance for what should be around 200' but showed up as closer to 10,000. Your suggestion just made the cad file 5280 times too big. I appreciate the suggestion though...I was hopeful.

Re: Acquired Coordinates in Revit don't match Autocad survey

barthbradley — Wed, 16 Oct 2019 16:56:00 GMT

That was an "oops" post.

I am at loss here. This one's out of my wheel house. If I remove your DWG's geolocation via "Remove Location", all is right as rain. I suspect that's not an option for you. Maybe @SteveKStafford can pop back in here. He's the real guru on this stuff.

Re: Acquired Coordinates in Revit don't match Autocad survey

SteveKStafford — Wed, 16 Oct 2019 16:58:51 GMT

The file you sent me linked without issues. I used Auto - Center to Center. The size of the geometry in Revit is the same as the size in the DWG...if Feet is the correct units. If this curve is a wall then it is a big wall (28'-8" thick). I used Acquire Coordinates and have the same coordinates reporting at the same corner of the "wall".

Re: Acquired Coordinates in Revit don't match Autocad survey

Anonymous — Wed, 16 Oct 2019 17:10:14 GMT

LOL! The wall isn't 28' wide, thats three walls that form a ramp for a railroad track grade change. There's 3 retaining walls there. 28' is the out-to-out dimension.

So I did exactly what you just described with that exact file I sent you and I get the dimensions shown in the attachment I am including here.

Re: Acquired Coordinates in Revit don't match Autocad survey

SteveKStafford — Wed, 16 Oct 2019 17:17:02 GMT

One subtlety... I deleted your long line to origin. Try it that way.

Re: Acquired Coordinates in Revit don't match Autocad survey

Anonymous — Wed, 16 Oct 2019 17:24:50 GMT

Made no difference. Same result.

Re: Acquired Coordinates in Revit don't match Autocad survey

SteveKStafford — Wed, 16 Oct 2019 17:26:55 GMT

What version of Revit? Which template did your project start with? Try doing the same with the Default architecture template.

Re: Acquired Coordinates in Revit don't match Autocad survey

barthbradley — Wed, 16 Oct 2019 18:11:51 GMT

@SteveKStafford wrote:
The file you sent me linked without issues.

Curious, Steve. I have issues with the Geolocated DWG. I link the DWG in Origin-to-Origin, Acquire Coordinates and the Survey Point Origin moves some 694 miles away from the Project's Orgin. But, when I remove the Geolocation from the DWG, and Link it into Revit Origin-to-Origin and Acquire its Coordinates, the Survey Point Origin doesn't move. Exactly what I would expect, since I Linked the DWG Origin-to-Origin and didn't move it. What am I missing here?

Re: Acquired Coordinates in Revit don't match Autocad survey

SteveKStafford — Wed, 16 Oct 2019 18:15:55 GMT

I didn't link it Origin to Origin. I used Center to Center. I never use origin to origin with CAD files, far too unreliable to do that. I also never add a line drawn to origin because it invariably creates a file whose extents are too large and generates a warning.

I only deleted the long line, linked it Center to Center and then Acquire Coordinates...screen captured values.

Re: Acquired Coordinates in Revit don't match Autocad survey

barthbradley — Wed, 16 Oct 2019 20:27:43 GMT

Yeah, I tried six ways from Sunday and can't get there. The only way I can get there is by removing the location data and assigned coordinate system from the drawing. Obviously, I'm missing something -- and it's probably staring me right in the face. This is bugging the crap out of me!

Re: Acquired Coordinates in Revit don't match Autocad survey

SteveKStafford — Wed, 16 Oct 2019 21:01:33 GMT

Don't use Origin to Origin...that'll never work. The survey data needs to be near Revit's origin. The only way that happens is to use Center to Center ... and move the survey/property there if still far away. Then Acquire Coordinates. If the Geolocation feature is active in the file then Revit will also assign its Location based on that data.

Re: Acquired Coordinates in Revit don't match Autocad survey

SteveKStafford — Wed, 16 Oct 2019 21:45:57 GMT

In 2018 I can link the file and Acquire Coordinates "as is" and get the correct coordinate values. In 2020 however I do not. I can resort to using Specify Coordinates at Point to define the Shared Coordinate System properly. Linking other files using By Shared Coordinates "should work" unless they too have some geomarker referencing issue.