How to use Classify Ground Points

[kogapen]

Hey there
I want to use the tools of Classify Ground Points.
And I made Tile Points,Depth Maps, Dense Cloud before using "Classify Ground Points".
Then I try to select a tools->Dense Clouds->Classify Ground Points from the menu tab.
And when I set the screen that came out and pressed OK, I got an error message "Unreferenced point cloud".
Please let me know if you have a good idea to solve this error.

System:
Metashape PRO Ver 1.5.2 7838 64bit

Best Regards,

[Dragline]

My guess would be that your project isn't referenced. This means that Metashape doesn't know which way is up (Which is necessary for classifying points). Did you use ground control points or have location data for where your photos were taken from?