Hi Ditto, I'm not sure if it helps you for your particular case here since you've got a whole bunch of closed overlapping circles as the things you're processing, but with open curves you can use booleans on curves to cut them to be contained within a particular closed outline, like this:



Then doing Construct > Boolean > Intersection will make this result:




But with closed curves like all your circles those will be interpreted as overlapping regions and they'll get combined together instead of just being cut by the boundary like will happen with open curves.

If you're able to easily reconstruct the circle pattern you might try making it made up of something like sets of 4 open arc curves and then trying the curve booleans on them to see if that helps get what you want.

Otherwise for such a large number of objects you'll be wanting to do a bunch of strategic window selections to select clusters of them at once rather than individual clicks. Some things that can help with that would be to lock the outer boundary (in the Scene browser hold down the Ctrl key and click on the eye icon to lock that so it can't be selected), then you'll zoom in and do a bunch of window selections to grab a batch of things to delete in one go rather than just individual clicks.

- Michael