Help with cutting multiple objects via Boolean, knife project or similar please!

I have 400 meshes that have been captured from a timelapse and imported into blender.
I have animated them all as each mesh is a frame, so they use keyframes to appear once at the relevant point and disapeer.
The issue I’m having is trying to tidy up the meshes. As they were moddelled by another program automatically the edges aren’t square and the mesh is complex.
I was hoping I could use one shape, (like a boolean or a knife project) to cut all 400 square edges.
Boolean worked, but I would need to duplicate the shape 400 times, apply the modifier 400 times and it isn’t really feasible.
Knife project didn’t give a smooth edge because of the mesh, but would also only cut through one.

I’ve attached an image of the shape I’m trying to cut, and the shape I’ve been using as a knife tool. If anyone can help I would be massively appreciative!


Could try adding the boolean on one of them and copy that to others. Select the objects you want to cut, select the one with the modifier added and set up, and ctrl+L -> modifiers to copy the modifier. If you then need to apply the modifier on all of them, alt+C -> mesh.

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