Python: How to delete and move vertices on multiple objects based on position

Question

I have a grid of objects that each have 2 separate shells in them (cube and sphere) What I want to do is delete the mesh in front, which would be all vertices where their Y position is less than 5. And then select the rest of the vertices and move them along the Y axis by -15.

For the deletion part I have found this script in another question:

import bpy
import bmesh

ob = bpy.context.object
assert ob.type == "MESH"
mat = ob.matrix_world
me = ob.data

global_z_plane = False

if me.is_editmode:
    bm = bmesh.from_edit_mesh(me)
else:
    bm = bmesh.new()
    bm.from_mesh(me)

for v in bm.verts:
    co = mat * v.co if global_z_plane else v.co
    if co.z < 0:
        bm.verts.remove(v)

if bm.is_wrapped:
    bmesh.update_edit_mesh(me)
else:
    bm.to_mesh(me)
    me.update()

This seems to work if I change the Z for a Y and the 0 for 5 but only for the selected object. I need it to do it with all objects in a collection with a specific name like 'Collection'. I've tried grafting together the code from another question I made previously, but I don't really know enough python to make it work. Can anyone help me with this?

Answer 1

you have to adapt the "coll1" to your collection name you need.

import bpy
import bmesh

for object in bpy.data.collections["coll1"].all_objects:
    
    if object.type == 'MESH':
        if object.mode == 'OBJECT':
            bm = bmesh.new()
            bm.from_mesh(object.data)
        else:
            bm = bmesh.from_edit_mesh(object.data)


        bm.verts.ensure_lookup_table()
        bm.faces.ensure_lookup_table()

        for vert in bm.verts:
            print(vert.co)
            if vert.co.y <= 5:
                bm.verts.remove(vert)
            else:
                vert.co.y += -15

        if object.mode == 'OBJECT':
            bm.to_mesh(object.data)
            bm.free()
        else:
            bmesh.update_edit_mesh(object.data)