Getting mesh's transformation

[rodrigoloc]

Hello.
I'm trying to do an exporter to my C/C++ geometry format. It works almost perfectly but I've got problems with the transformation.
How can I get the mesh's transformation?
When I write at the python console 'bpy.data.meshes[0].vertices[0].co' the output is (-1.0 ; -1.0 ; -1.0) (it's an example), but when I rotate the mesh at the 3D View, it continues being the same output at the console.

Here's the code (I'm not very good at python):

filename = bpy.path.ensure_ext(self.filepath, self.filename_ext)
file = open(filename, 'wb')
d = bpy.data
mc = len(d.meshes)
array('i', [mc]).tofile(file)
for i in range(mc):
mesh = d.meshes
vc = len(mesh.vertices)
array('i', [vc]).tofile(file)
for j in range(vc):
vertex = mesh.vertices[j]
for co in vertex.co:
array('f', [co]).tofile(file)
for normal in vertex.normal:
array('f', [normal]).tofile(file)
pc = len(mesh.polygons)
array('i', [pc]).tofile(file)
for j in range(pc):
polygon = mesh.polygons[j]
pvc = len(polygon.vertices)
array('i', [pvc]).tofile(file)
for k in range(pvc):
array('i', [polygon.vertices[k]]).tofile(file)
file.close()
return {'FINISHED'}

[CoDEmanX]

you need to multiply the object's world matrix with the mesh coordinate to get an absolute coord:

ob.matrix_world * me.vertices[#].co

but it's more efficient to use to_mesh(), which lets you apply modifiers and shape keys, take that new mesh and do Mesh.transform(ob.matrix_world). If you then access the verts, they will be already in global space.

[stiv]

One thing that noobs find confusing is that blender objects have two parts - Object and ObjData:

* The Object part holds the spatial information for the object - the location, rotation, scale . This is the world transformation matrix.

* The ObjData part holds the geometry - in the case of a Mesh, this is the verts, edges and faces that make up the object.

Each object has its own Object part, but a single ObjData can be shared among many Objects (linked duplicates)


The other helpful bit is the Code tag here on the forums which keeps phpBB from eating your Python formatting.

[rodrigoloc]

Thanks you two. It works perfectly.

Here's the code:
mesh = d.meshes
mesh.transform(d.objects[mesh.name].matrix_world)

[CoDEmanX]

note that this will change the original mesh!

if you don't want that, use a copy of the mesh and remove it afterwards