coordinate system issues when converting .las file to .rcp file in Recap and exporting to Revit 2019

[Maraten86]

Hi!

I am currently having issues aligning point clouds for a project in Revit 2019. I have used Pix4d to create the point clouds to .las files and then converting them to .rcp files in Recap to be able to export them to Revit. 

Pix4d is using WGS 84 as coordinate system and the coordinate numbers exceed 30000 so the point clouds are positioned far away from the point of origin.

When moving and trying to align the point clouds it will not let me move the position of the cloud in smaller increments than 30 cm which makes the model inaccurate. 

I tried changing the point of origin in Recap (https://knowledge.autodesk.com/support/recap/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/Reality...) but the coordinates do not change.

Does anyone know how to fix this issue? I would very much appreciate it.

Kind Regards,

Jonathan Marat

[Pointdump]

Andreas,
"Pix4d is using WGS 84 as coordinate system and the coordinate numbers exceed 30000..."
I'm confused. WGS84 shouldn't have any Coordinates larger than 180 for Longitude or 90 for Latitude.
Dave

[Maraten86]

Hi Dave,

thanks for the reply.

To clarify WGS 84 is the coordinate system pix4d is using (screenshot 1), consequently the computed coordinates for the points in meters is larger than 30000 (screenshot 2) and as a result Revit cannot import it properly (screenshot 3).  

Have a nice day/Jonathan

[Pointdump]

Jonathan,
I've never used Revit. Does Revit need geo-referenced point clouds? How about using an "Arbitrary Coordinate System [m]"?
Dave

[Maraten86]

Ok. We tried that, when we reprocess with arbitrary coordinate system the scale of the point cloud changes dramatically which makes it very small. Maybe smaller than a 1 m x 1 m. The scan that we have is of a whole city block. If we don´t use an arbitrary coordinate system it is in the correct scale.

Revit doesn´t need georeferenced point clouds but the computed position of the points is what Revit is referencing to and places the point clouds far away.

Take care, 

Jonathan

[Pointdump]

Jonathan,
I tried playing with the 2 "Origin" buttons and had to conclude that I haven't the slightest idea what, if anything, they do.

CloudCompare will truncate the coordinates, but ReCap then maddeningly scales both the horizontal and z when you attempt to denote the cloud as feet.

Dave

[yan.fu]

The update origin tool should be able to reset the origin to small coordinates. 

If Revit doesn't recognize the UCS set by update origin tool, you can try to export the project to a unified .rcs to see if it works. 

Hope it helps.

Best,

Yan

[Pointdump]

Yan,

"The update origin tool should be able to reset the origin to small coordinates."
I tried changing the X and Y, then hitting OK. No change. What am I doing wrong?
What is a "unified .rcs"?
ReCap desparately needs an expanded Help Section. I've read the Help from top to bottom, and honestly, I've learned more by bumping around, clicking things, and reading Forum Posts.
Dave

[Pointdump · Accepted solution]

Jonathan,
From @Maksim.Melnikov.BY >>>Here<<<, when using "Update Origin", leave the X and Y unchanged and change Z to 0. Totally un-intuitive, but it works.
Dave

[Maksim.Melnikov.BY]

Hello @Pointdump 
If you are interested in the technology of working with a point cloud in Revit, then of course there are certain specifics, since Revit has restrictions on the distance of model objects from the model origin.
I can describe to you the workflow that I use:
1. If the proposed object is located at a great distance from the origin of the GEODETIC coordinate system, then in ReCap you need to create a conditional coordinate system with the origin on your construction site. (As a rule, I choose the intersection of the geodetic coordinate axes, for example 512200, 2635800) Leave the height true 0.000.
2. This offset must be fixed in the project so you can link your Revit model to a Civil 3D, Infraworks, or Nawisworks model in the future. That is, the overall coordination model must be in a true GEODETIC Coordinate System!
3. Insert a point cloud in Revit with the parameters "By common coordinates"
4. Thus, in Revit you work with conditional X, Y, which are offset relative to the true geodetic system by 512200m, 2635800m. The height in the model is true.
5. When the Revit model is ready you can transfer it to Civil 3D, Infraworks, Nawisworks. Just when importing a Revit model into infrastructure programs, you specify the offset of the model - 512200m, 2635800m. This will set your model to its true survey position.
I apologize for my English, I hope you have an understanding.

[Mederick.Grenier8TPPP]

Hi there,

I understand that you were having a similar issue as another user and were able to find a solution. It seems that when using the "Set origin coordinate" tab in Autodesk Recap, inputting 0 for X and Y actually performs a translation of 0 meters, while inputting a value in these fields will perform a translation of that value. 

To clarify, when you leave X and Y as XXXXXXX and YYYYYYY and input 0 for Z, Recap will perform a translation of XXXXXXX and YYYYYYY. This is why the origin appears near 0,0.

I hope this information will be helpful to other point cloud users who may encounter similar issues. Let me know if you have any further questions or concerns.