UV-Real World scale

Realworld Scale Unwrap

Found a script by Igor Znag.
Select all vertices in Unwrap and then apply script.

macroscript unwrap_uvw_real_world_map_size category:"_igorznag" buttontext:"RWMS"
(
if selection.count==1 then
(
obj=selection[1]
if superclassof obj==GeometryClass then
(
m=undefined; m_count=0
for i=1 to obj.modifiers.count where classof obj.modifiers[i]==Unwrap_uvw do (m=obj.modifiers[i]; m_count+=1)
if m!=undefined then
(
if m_count==1 then
(
obj_mesh = snapshotasmesh obj
n=obj_mesh.numfaces
if n>0 do
(
mesh_area=meshop.getFaceArea obj_mesh #{1..n}
uv_area=0
for i=1 to obj_mesh.numfaces do
(
tv_face=getTVFace obj_mesh i
v1=getTVert obj_mesh tv_face[1]; v2=getTVert obj_mesh tv_face[2]; v3=getTVert obj_mesh tv_face[3]
a=length (v2-v1); b=length (v3-v1); c=length (v3-v2); p=1.0*(a+b+c)/2
area_=sqrt(p*(p-a)*(p-b)*(p-c)); uv_area+=area_
)--for i=1 to obj_mesh.numfaces do

if uv_area!=0 do
(
n=m.NumberVertices(); aspect=sqrt (1.0*mesh_area/uv_area)
undo on
(
for i=1 to n do
(
vp=m.getVertexPosition 0 i; vp*=aspect; m.SetVertexPosition 0 i vp
)--for i=1 to n do
)--undo on
)--if uv_area!=0 do
)--if n>0 do
delete obj_mesh
)else "Select one geometry object with one Unwrap UVW modifier!"
)else "Select one geometry object with Unwrap UVW modifier!"
)else "Select one geometry object!"
)else "Select one object!"
completeredraw()
)--macro