Apply location sets local origin to global

Via the UI can set an objects origin to global origin (scene (0, 0, 0)) by applying location CtrlA Location

equivalent of calling

bpy.ops.object.transform_apply(
    location=True, 
    scale=False,
    rotation=False
    )

At a lower level.

Method to set the origin of an object to a global location, without moving the object ie the vertices remain in the same global location.

Setting the origin for each object to geometry

Set origin to bottom center of multiple objects

• Get the local coordinate of the new origin
• Subtract it from all coordinates
• Set the global translation to new origin location

Test script:

import bpy
from mathutils import Vector, Matrix

def set_origin(ob, global_origin=Vector()):
    mw = ob.matrix_world
    o = mw.inverted() @ Vector(global_origin)
    ob.data.transform(Matrix.Translation(-o))
    mw.translation = global_origin
    
# test call

set_origin(bpy.context.object)

Answer toward "Snap object to (0,0,0)"

You can use both operator or built-in method:

Operator

• bpy.ops.object.location_clear(clear_delta=False)

This is equivalent to the button in Object → Clear → Clear Location (Alt + G) And you can set clear_delta parameter if you want to clear delta-transform as well.

built-in method:

• obj.location = Vector((0,0,0)) (where obj is Blender object)

• obj.delta_location = Vector((0,0,0)) (Clear delta location)

This give you direct(kind of) assess to location value, which should be saved as a Blender's Vector

---

Operator will somehow rely on context when you call it, so the scene, selected objects, other possible associate content should be set properly. And I personally don't like to use operator in script because they are wrap function set that should be used in User Interface, making it hard to guess what will the operator do when you call it.

---

Original Answer toward "Set object origin to (0,0,0)"

It is not as easy as you think in this task due to the lack of the function implement.

The object origin is actually a descriptor for inner data. You can change the descriptor directly. But data didn't change inside so the position you see will be different, that's not we want.

Approach

• Use Blender bpy operator to do your task. The 3D cursor and set origin operator. (easy)

import bpy
from mathutils import Vector, Matrix

def bpy_set_origin(location=Vector((0.0, 0.0, 0.0))):
    # store the location of current 3d cursor
    # must copy the location since that's a reference.
    saved_cursor_location = bpy.context.scene.cursor.location.copy()

    # set 3d cursor to desired location
    if isinstance(location,Vector):
        bpy.context.scene.cursor.location = location
    else:
        print(f"Invalid location given:{location}")
        return
    # set object to new location
    bpy.ops.object.origin_set(type='ORIGIN_CURSOR')
    # restore former location
    bpy.context.scene.cursor.location = saved_cursor_location

if __name__ == "__main__":
    bpy_set_origin((0, 0, 0))

• Modify origin directly and make data consistent with the change

import bpy
from mathutils import Vector, Matrix

def directly_change_origin(
    obj,
    location = Vector((0.0, 0.0, 0.0))
):
    # Get the original translation
    translation_vector = obj.matrix_world.translation @ obj.matrix_world
    # Make a tm for transform
    transform_matrix = Matrix.Translation(translation_vector)
    # Make object 
    obj.data.transform(transform_matrix)
    obj.matrix_world.translation = location
    
if __name__  == "__main__":
    if bpy.context.active_object.mode != 'OBJECT':
        bpy.ops.object.mode_set(mode='OBJECT')
    
    selected_list = bpy.context.selected_objects
    for obj in selected_list:
        directly_change_origin(obj, (0, 0, 0))