Problem with shared coordinates when linking two projects

[Anonymous]

Hello,

I have a question about coordinates in Revit. I have read myself in on the use of coordinates in Revit and searched on forums for the answer on my problem but could not find an answer to my problem.

The situation:

I’m working on a project within a consortium and there are 2 companies working on developing in Revit. These models need to be combined into one project file. (the models are also project files, not families)

The problem:

When I am in a file of company 1 (my company) and link in a Revit model from company 2 by shared coordinates I get the error: The document and the imported instance do not share the same coordinate system. Default center-to-center positioning will be used. This center-to-center positioning is off and the model is placed in the wrong place.

Known aspects:

The strange thing is, as far as I know both models use exactly the same coordinates. The Survey Point is the 0.0.0 point which standardly is based upon the World Coordinate System (WCS) and is in default always (by my knowledge) clipped on the 0.0.0 (It is on both projects) and the Project Base Point is relocated to the coordinates of the project itself, these coordinates are:

North/south:                     447457137

East/west:                          135973507

Elevation:                           0

Angle to True North:      286.368

But when I import Object A from Compony 2 into my own project ( Insert - Link Revit, project from company 1) it says we are not using the same coordinate systems. The object is then located to another place in the project, and when I check the coordinates of Object A ( Annotate - Sport coordinate) it shows a different coordinate then in its original project file.

My probable causes

In my opinion it may have been caused by one of two reasons:

1. Somehow the Survey Points are on different locations even though in Revit they both say 0.0.0. Which would be very strange since I read online this is the WCS which in 0.0.0 should always be on the same spot.
2. The coordinates in both projects have been acquired from two different worksets. Both are DTB (Digital Topographical files from the Netherlands) but one is the complete file and the other one is a partial DTB file. They both result in exactly the same in project coordinates but maybe the use of different files for acquiring coordinates shifted some settings somewhere.

Primary Question: How can I fix this error and set them both on the same (and correct) coordinates? (even though according to Revit they already both are on the correct coordinates)

Secondary Question: If the above coordinates of the Project Base Point match does this imply that both projects have the same coordinates?

I’m really hoping someone understands what is going wrong here and can point me in the right direction. All the help would be appreciated. If more information is needed let me know I will add it.

Regards,

Peter

[Keith_Wilkinson]

Shared coordinates need to be set up - generally we find it's best to do this using a separate site file that has been set up using reliable survey data - then we link our model(s) locate them on the site and push the coordinates back out to them.  You do this with all the revit project files after which you will be able to link them using shared coordinates.

In your case, have you tried linking the files but selecting Origin to Origin?  If the models have been built off each other, and from what you have indicated above it may be that they share the same origin point, if not I'd suggest following my suggestion above - I can send you some notes we use here that might help.

HTH

K.

[Anonymous]

Thank you for your quick answer, forgive me for asking simple questions but the more I'm working with it the less I understand it. What exactly is setting up shared coordinates. I see a lot of different information in youtube videos and online and this fails to get clear for me.

Is setting up shared coordinates simply opening up a new file and place the Survey and/or Project Base Point to the desired coordinates? (e.g. Survey point on 0.0.0 and PBP on the coordinates from my original message?) Or does it need to be you load an AutoCAD file and acquire the coordinates?

I would like to see your notes, hoping they can give me some more insight in this problem.

Regards,

Peter

[Keith_Wilkinson]

No, you need a minimum of 2 files to make use of shared coordinates.

Lets say you have project A (maybe your architectural model) in which you have set the coordinates at a known location and rotated north to the right location.  Now you have project B (structural model perhaps) that you want to share the same location as Project A.  You would link Project B into Project A and then 'Share' the coordinate system with Project B.

essentailly what this is doing is storing data against the location and rotation of the survey base point but with the approach I've outlined in my oriignal post (notes attached here) you don't need to worry about that.  Just have a site file and coordinate everything through that, it's an approach that makes sense to most and generally won't let you down.

[jkarben]

I agree with Keith if origin-to-origin aligns the two models stay with that. If not....

Determine the source file. It could be model 1 or model 2. Let's say it is model 1.

1. Open model 2.
2. Link model 1 center-to-center*.
3. Move linked model 1 into position.
4. Acquire Shared Coordinates from model 1.
5. Remove linked model 1.
6. Link model 1 by shared coordinates and they will now align.

Model 1 is the source so no work needs to be done to it. When you determine which office has the source model the other office will need to do the "acquiring".

If the source file is a separate Revit site model or CAD site plan it would copied between the two offices and both model 1 and model 2 would acquire the coordinates from it following the steps above.

* Using center-to-center puts the two models close to each other based on their geometry where another linked relationship may be way off.

[Keith_Wilkinson]

I generally find that publishing shared coordinates works better than acquiring simply for the fact it can be done multiple times without problem, whereas once you have acquired coordinates you have to jump through hoops to acquire again should things change.  I've not checked this in 2017 but it certainly has been my experience... 

[jkarben]

The linked relationship between the various building models (Arch shell, Arch interior, Stuct, MEP, etc) is often carried through as an origin-to-origin relationships when one model is first shared with the others and linked origin-to-origin before their work commences.

Linking by shared coordinates is used to:

A) Define relationship to a site model/CAD plan.

OR

B) When building models are started independently of each other and will not align origin-to-origin.

[Anonymous]

Thank you, I used your steps succesfull with a small difference.

In stead of moving Model 1 (the linked model) I moved model 2 to the right coordinates after acquiring coordinates. This because model 1 is a empty template file with only the Project Base Point on the right coordinates. But after doing this I believe everything worked as it should. So everybody thank you very much for your helpfull answers and now I can sort it all out.

Regards,

Peter

[jkarben]

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@Keith_Wilkinson wrote:

I generally find that publishing shared coordinates works better than acquiring simply for the fact it can be done multiple times without problem, whereas once you have acquired coordinates you have to jump through hoops to acquire again should things change.

---

I agree. Although It could cumbersome for a MEP consultant to open up his copy of the architects model and publish to his/her MEP model.

Which gets me thinking....never tried this but if they were initially acquired from a linked model and they subsequently changed could one turnaround and publish to via the linked arch model to get by without go through the resetting hoops....hmmmmm. Sorry off topic.

[Keith_Wilkinson]

Hi Peter,

Please see my comment above regarding acquiring coordinates - this will work once but will be problematic for you if you need to do it again with the same model.  Publishing coordinates is more robust.  If you have got to where you need to be just now that's great but bear it in mind in future or if you need to make changes to this project.

I take it Origin to Origin didn't work?

if you are happy with the solution then please mark the appropriate reply(s) as a solution.

[Keith_Wilkinson]

This is why we use a site model.  So long as you have an agreed known point marked in your model (at a specific grid intersection for example) then life is easy.  You issue the site model and just let everyone link in their own model to this file and publish from there.

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@jkarben wrote:

---

Which gets me thinking....never tried this but if they were initially acquired from a linked model and they subsequently changed could one turnaround and publish to via the linked arch model to get by without go through the resetting hoops....hmmmmm. Sorry off topic.

---

Whether your solution would work I can't say, to be honest I can't even recall the method of resetting it other than it required an empty file with no previously shared coordinates... we simply developed a methodology that works and stuck to it,less hassle all round.

[KIMRAMFI]

Sorry wrong thread.