Detect if faces on buffer geometry overlap

hello lovely people,

i have created a simple demo here…

i have set it up so if the big boolen button (top left) is clicked, a new CSG union mesh is created and added to the scene, then when the “detect / remove faces” appears, i am tyring to detect where the bufferGeometry faces of the new CSG union mesh overlap the original mesh’s bufferGeometry faces so that bufferGeometry faces on the original mesh that are not being intersected can be seleted and removed

i hope this makes sense and someone can help me as i’m really stuck!!


I’ve managed to make some progress and set rays to cast from every face of the CSG geometry which in turn will now console log intersects[ 0 ].face of the original object

would anyone know how i would either remove any faces from the original geometry not intersected by the rays, or how i would build a new geometry from only the faces that have been intersected?

here’s the updated live example

thank you in advance, any help would be greatly appreciated!!