Registering Two Point Clouds

[frankcloud]

Hi everyone,

I’m having trouble registering two point clouds in CloudCompare, and I’m hoping someone can help me figure out what’s going wrong.

I’ve loaded both point clouds into the DB Tree and successfully selected three points on the "to-be-aligned entities" cloud using the point-pair registration tool. However, when I try to switch to selecting points on the "reference entities", the tool doesn’t allow me to proceed. I've also attached a screenshot for reference.

Here are the issues I’m encountering:

The "Reference entities" section in the point-pair registration window is completely yellow, and the checkbox next to it is unselectable. I can’t activate it to begin picking points for the reference cloud.
Clicking the pencil icon (🖉) for the "reference entities" doesn’t change anything—it remains inactive.
I’ve tried ensuring both point clouds are properly selected in the DB Tree before starting the registration tool, but the issue persists.
Even when I restart the process or select different point clouds, I can’t seem to shift from the "to-be-aligned" cloud to the "reference" cloud to pick corresponding points.
Has anyone else run into this issue, and do you have any suggestions for troubleshooting? I’m wondering if I’m missing a step in activating the reference entity or if there’s something else I should be checking in the DB Tree.

Thanks in advance for any advice!

[daniel]

After you select the 2 clouds and start the tool, you should see a small dialog with the list of selected entities (2 in your case I guess).

In this list, you have to select only one of the 2 clouds to indicate which cloud is 'to-be-aligned'. Do you see this dialog and are you able to select only one cloud with it?