Linked Point cloud(rcp) ends up slightly off

[Arvid_Malm]

In the project I'm currently working wtih we have an existing building that we're connecting a new building to. So we've recieved a point cloud (rcp) that seems to be accurate when it is linked in to NavisWorks and AutoCad. Also our Revit file have correct coordinates so our dwg exports ends up in the right place(in our national(swedish) coordinate system).

So far so good...

But when we link the point cloud into Revit the point cloud ends up a litte bit off. Just a little bit both in rotation(less than 1 degree) and also x-/y-wise around 200mm at the most/worst points.

Since everything seems to match I'm pretty sure it's something wierd that goes wrong in the linking process. But I honestly have no clue.

Has anyone experienced anything similar and is there perhaps a solution to the problem or maybe a workaround?

[barthbradley]

How far from the Internal Origin is the PC Origin?  

https://knowledge.autodesk.com/support/revit/troubleshooting/caas/CloudHelp/cloudhelp/2019/ENU/Revit....

[Arvid_Malm]

Quite far, but isn't that kind of always the case when working with coordinate systems?

[barthbradley]

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@Arvid_Malm wrote:

Quite far

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Well, there you have your explanation. Curvature of the earth probably.  Pretty much what that Link talks about.  Maybe the better workflow in this case would be to move the PC into the correct position relative to the Building Model, pin the PC and leave it alone.  Or, Link the PC into its on RVT and Link that PC/RVT into the Parent RVT.  

[Arvid_Malm]

You're probably right. But I find it very strange that everything works perfectly in the other Autodesk softwares but not in Revit. The curvature of the earth shouldn't vary between them.

I'm a bit hesitant to moving the PC since I then will be the one responsible for the accuracy of the positioning. But on the other hand I'll rather have it almost exactely right than not right at all.

I'm gonna try the link workflow suggested and see if that solves anything although I'm afraid I'll end up with the same result.

Thanks for the input!

[Arvid_Malm]

I tried to link it into a seperate Rvt but I couldn't make the pointcloud visible in my main Rvt-model. So now I'm trying to move the Point cloud but it seems thats a bit trickier than I thought(since ReCap wont let me import Cad-files and thats, as far as I know the only way to get the exact positions/rotations of the shared an internal project zero.

Anyone who've done this before and got a method that works?

[barthbradley]

Try it the other way around then. Link the Parent RVT into the PC RVT, position the Parent Link correctly in relation to the PC, and then Acquire Coordinates of Parent RVT Link.  Afterwards, Link the PC RVT into Parent RVT via Shared Coordinates.   

[Arvid_Malm]

That could have worked if the coordinates were incorrect. The problem is they arent, it's just Revit that are having problems with the far away distance to "zero". So what I'm trying to achieve is getting the "zero" closer to the building.

How Autodesk haven't got a solution/method for this is truly wierd.