Maybe these examples from the Collection of examples from discourse.threejs.org are helpful.
https://hofk.de/main/discourse.threejs/2018/Interaction%20with%20Points/Interaction%20with%20Points.html
https://hofk.de/main/discourse.threejs/2018/PointsGroupingCutPlane/PointsGroupingCutPlane.html
https://hofk.de/main/discourse.threejs/2019/PointCloudGegometryModification/PointCloudGegometryModification.html
Links in sourcecode.