Ground Control Point Weirdness

Development World Creation
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1

Having some issues with GCPs. After reading a number of threads and trying a few different things, the GCPs don’t seem to quite work out.

I’m following the instructions as outlined here: https://support.capturingreality.com/hc/en-us/articles/360001577032-How-to-geo-reference-the-scene-in-RealityCapture-using-ground-control-points-faster

My flow:

  • Import 400 drone nadir images
  • Align (this results in one comp with all the images)
  • Import GCPs (below screen shot is after alignment GCP alignment)
  • Choose “Set to the Project” for coordinate system
  • The GCPs seem to register OK. Here is what the map view looks like:
  • Place the GCPs on images. They all look like this:
  • Go to RC Settings and set “Ignore GPS Exif = True” (read somewhere that it may cause issues if image GPS data is used)
  • Align again
  • Everything aligns, but the component is tilted and 2 of the 4 GCPs have a large error (as seen in one of the above screen shots)
  • The component looks like this:
  • NorthEast and NorthWest points are offset from "true ground)

Could it be that the initial alignment, before GCPs, is messing things up? The “How To” post seems to do it the same way.

Any thoughts or suggestions are greatly appreciated.

2

Hi Tim

Please clean cache and then realign once again the photos with the GCP or try once again but switch of the GPS information in Exif at first alignment. Please check as well your GCP data, and make sure that you set correct coordinates

3

Ah, of course. Thanks, Rafa.

Clearing cache seems to have helped. 

4

So clearing the cache made things slightly better, but not by much. 

New flow:

  • New project, clear cache
  • Import GCPs
  • Set “Ignore GPS Exif = True” in RC settings
  • Import images 
  • Place the GCPs on appropriate images
  • Align 
  • Component is still tilted. Looks like this: 
  • Control point info looks like this: 

Looks like Southwest and Northwest are offset in the 3D view and have a large error. 

Any suggestions? 

5

In your first example Northeast and Northwest GCP show errors, now it’s Southwest and Northwest. 
Please check your control points. What coordinate system do you use? 

6

I have the same issue

the GCP are accurat and even if there is jsut ONE the model tilts

any clue
__________

UPDATE:
i created everthing new in a new file ignoring GPS from images and it worked out perfectly

BUT it is a pitty that in need to put everthing into trash to ajust the orientation to GCP…

maybe this could be a bit easier and not through timecunsuming recalculations

UPDATE 2:

Errors again!!

After adding additionals points after i created the allingment it breaks everthing

this is such a pitty

 

 

7

Rafa,

The control points should be good. Also, checking the map shows them in the same position as before:

The errors and offsets seem to show up randomly every time I start over.

Coordinate system is epsg:4326 - GPS (WGS 84)

 

8

Tim, 

Please could you paste here print screen or send through the contact from on our website, coordinates of your all control points that you are using in the project (Long,Lat, Alt) 

9

Rafa,

I sent an email with the control point data through a “Contact” form on your website. 

Please let me know if you’ve received it.

10

Hello Tim,

Yes, mail well received, thank you. 
Would be possible for you to share with us all data for this project that we could reproduce scenario and see what else can be the issue in this particular case?

We will need project file with extension *.rcproj and project folder with all *.dat files, as well original photographs and GCP. 

11

Rafa,

I’ve replied with the share links for the data requested.

Please let me know if you’ve received it.

Thanks