Suddenly Pointcloud is offsetted when imported in Revit

[virtuoso]

I had georeferenced my pointcloud in Register 360, all good. Put that in Recap also checked coordinates briefly and they were fine. After that I imported in Revit, set project base point at one of the markers and loaded .rcs by shared coordinates. All good. I then linked that rvt file into my model file and that was also good. We managed to model whole building just fine. And then suddenly my pointcloud was not loading. Tried to reload, nothing (even it said that it was loaded). Went back into revit file where pointcloud is originally loaded did reload and suddenly in that file my marker from pointcloud wasn't anymore exactly on project base point. Now it is offsetted.

Did anyone experience this?

After that I created new file and it loaded fine where it should, link that back into model... Pointcloud is then again invisible, then whenever I go back to Rvt where pointcloud is loaded it is suddenly offsetted. What should I do?

Luckily whole building is done. Now we need to send model to our customer but I can't get pointcloud fit anymore.

[jamesworrell]

My 2c .. don’t georeference (large coordinates). Ever.

In Revit’s case, using metric point cloud? The unit conversion on the point cloud family is only to 4 decimal places .. clouds can drop in half a metre out due to rounding and huge distances from origin.

If you have your project base point, control etc, republish point cloud to suit project coordinates.

[virtuoso]

I'm afraid that is not the option atm. We already did project like that but in Revit 2021. No problems whatsoever. The worst thing is that I tried multiple times importing rcs for that project now and sometimes it falls correctly but then it is not visible when importing to project. Then while reloading it goes off.

What is usual practice when havin georeferenced PC yet Revit is struggling with large coordinates? Truncating? For that I will need Cloudcompare, but for that I need decimate pointcloud and lose quality. How then explain that to our customers.

Sometimes we have projects larger than 600 scans, and Register itself starts freezing after 500ish + stations. Then we need to create multiple sitemaps for splitting pc in smaller pieces.

[jamesworrell]

Yep we truncate. We actually run multiple ucs’s in cyclone which propogate to lgs.

We also typically decimate and tile for our revit users.

internally we use LGS with cloudworx.

As for rego, we do 100-200 scan registrations in r360, finalise in core. Then merge up using copy by reference in core. 500 scans would be 2 or 3 cyclone databases.

Full rant on geodetic coordinates:
https://www.bennettfrancis.com.au/2020/ ... es-part-1/

[virtuoso]

Yep we truncate.

We also typically decimate and tile for our revit users.

internally we use LGS with clourworx.

So I have an idea. Could it be possible that immediately in .txt file for control file, I let's say subtract from N/S coordinates that is 55231253 (random number) 55230000 so that I get like 1253 which is bearable for Revit. And same procedure let's say for E/W . Elevation of couple of hundreds meter is fine i wouldn't touch that. And repeat this for all targets in project? that would be some sort of truncation in Register 360 immediately. Then I wouldn't need to go through cloudcompare? What is your strategy for truncation if you don't mind sharing? Thanks for response.

I'm kinda new into this world of surveying and preparing clouds for modeling. So any advice would be great.

[jamesworrell]

we go with whole kilometres .. as long as all of site is positive coordinates .. so yeah you might end up with a 900 to 1209 say range if that makes sense? As opposed to -100 to 200 range.

[virtuoso]

we go with whole kilometres .. as long as all of site is positive coordinates .. so yeah you might end up with a 900 to 1209 say range if that makes sense? As opposed to -100 to 200 range.

To be honest i dunno if you are thinking the same as myself a bit confusion here from my side. What do you mean by whole kilometeres? like without decimal position or what?

For example if I have coordinates 5224402.8410 northing and 258521.1760 easting, would it work If I enter in .txt file 5224402.8410-5220000.8410 = 4402 N/S and from 258521.1760 subtracting 250000.1760 = 8521 ? Elevation can stay because it's in hundreds of meters. Virtually that would mean like I grabbed point and moved it in x-y plane. Also I repeat that for other targets (all the same numbers for subtracting). In that way I can enter PBP coordinates with this and if they need later georeferenced, I can specify coordinate on that point to be like it was in surveying. Dunno if you understand what I mean

[jamesworrell]

coords on control would be 402.841 and 521.176 ...

basically move origin to the neatest 1km intersection south-west of site .. so all coords are positivr ..