Point clouds in revit misaligned

[sam.stibbs]

I'm having an issue with point clouds in Revit whereby when I attach in overlapping point clouds they are becoming misaligned upto 40mm in x and y

I know that the point clouds are fine as I have double checked them within Civil 3D and they align perfectly fine. It is only when they are brought into Revit that the issue appears?

Can anybody shed any light on why this might be?

[Viveka_CD]

Hi @sam.stibbs

Which version of Revit are you using? Can you confirm if you have the latest updates installed for your Revit version?

Regards,

[sam.stibbs]

Hi @Viveka_CD,

We're using Revit Build 17.0.416.0 20160225_1515(x64). We are unable to get a later version of Revit at present.

[Viveka_CD]

Hi @sam.stibbs

To make sure that the issue you are seeing is not something already fixed in one of the product updates, I would suggest checking the Desktop App to see if there are any Revit updates available. For information on using the Desktop App see the following article: About the Autodesk Desktop App

Note: If you are not able to download updates through the Desktop App, the following article has information on downloading updates through the Autodesk Accounts page: Install Updates, Add-ons, and Enhancements

Coming back to your point cloud, is the file from a 3D scanner or another software?

Which positioning have you tried to align the coordinates? Are there large differences in the distance?

Do you get an error message when you link the point cloud?

Can you post screenshots?

This point cloud alignment idea request is also in the Recap ideas forum

Looking forward to your reply.

Regards,

[sam.stibbs]

@Viveka_CD 

The point cloud is from a terrestrial laser scanner and its made up of multiple scans. We don't have the original scans off the scanner but we have the processed scans which are in London Survey Grid. These scans are aligning within Civil 3D but when attached in Revit they become misaligned. I'm not sure if this is to do with the precision of Revit and the number of co-ordinate digits it can process and potentially the way the co-ordinate system is setup?

It is offset between 20-40mm in x and y across the project which covers a large area. When we attach in the surrounding point clouds we get the message that the 'co-ordinates of the points in the point cloud files you are trying to import are larger than 3000. Importing files may result in undesirable graphic behaviours'

[Viveka_CD]

Hi @sam.stibbs

You get this error message due to minor scaling issues from the origin.

 Modifying the scale value is suggested if units of the source data have not been correctly determined during import of the point cloud file.

1. When inserting a point cloud, Revit uses a scale factor, corresponding to International Feet, of 3.280840. The scale factor is truncated to 6 decimal places.
2. Changing the scale factor to 3.280833 (corresponding to US Survey Feet), the point cloud coordinates are short because the decimal places are truncated to 6 decimals. This means a survey coordinate of 1,700,000 feet now appears 2 inches smaller inside Revit.
3. Point Cloud > Properties Palette > Edit Type > Scale.
4. See the screencast HERE

Let me know if this helps resolve your issue.

Regards,