Blam & object size

Hello and thanks for any answers
I have used Blam to set the camera for my project
The plane in my file is scaled to fit the pic but is not the correct size
I have measured the distance at 8.78m - the plane is 15m

Any ideas?


Backyard 3.blend (989 KB)

Since it seems lines follow perspective fine i’d just drop scene Scale to 0.5 in order to get close to real numbers.

It’s possible to scale the object towards or away from the camera and it won’t change the way the object looks through it. Could use 3D cursor pivot. With that you’ll be able to still see the dimension value of the object while scaling towards the camera (apply scale afterwards, ctrl+A -> scale), or see the edge length display in edit mode if you scale the mesh.