Python - absolute position of face

Question

How can I get the absolute position in 3d space of a face using python. I can get the position relative to the object origin using face.calc_center_median() this is not the absolute 3d position.

Here is how I got the relative position:

import bpy
import bmesh

# get current mesh
current_mesh = bpy.context.object.data

# create empty bmesh, add current mesh into empty bmesh
current_bm = bmesh.new()
current_bm.from_mesh(current_mesh)

# TODO: get absolute position
# get location of face (atm it relative to object origin)
for face in current_bm.faces:
    face_location = face.calc_center_median()
    normal = face.normal
    x = face_location[0]
    y = face_location[1]
    z = face_location[2]
    print('index: '+str(face.index), x, y, z)  # DEBUG


# current_bmesh back to mesh
current_bm.to_mesh(current_mesh)
current_bm.free()

In this scene for example the cube is a good distance from the world origin, the absolute 3d shall reflect this.

These are the reported coordinates of each face (they are relative to the origin of the object)

Answer 1

Multiply it with the object's world matrix.

loc_world_space = obj.matrix_world * loc_obj_space

where loc_obj_space is a 3d mathutils.Vector

There is an addon View3D-> Math Vis(Console) available to visualize vectors and matrices directly in the viewport.

I.e. paste the following lines to the interactive console

obj = bpy.context.active_object
lobj = [vertex.co for vertex in obj.data.vertices]
lworld = [obj.matrix_world * vector for vector in lobj]