Recreating History: Pretoria 1947

"Photogrammetry is the science of making measurements from photographs, especially for recovering the exact positions of surface points. Photogrammetry is as old as modern photography, dating to the mid-19th century and in the simplest example, the distance between two points that lie on a plane parallel to the photographic image plane, can be determined by measuring their distance on the image, if the scale (s) of the image is known." - Wikipedia

Have you ever wondered how your hometown looked 50+ years ago? Well, if you have access to Recap Photo and some old aerial photos you will very likely be able to recreate your own piece of history. I sourced some old aerial photos of Pretoria, South Africa from the Institutional Repository of the University of Pretoria and by using Recap Photo, achieved some amazing results!

The images below are of individual aerial photos taken in 1947. I was amazed by how rural some areas were - Areas where today there are major residential, commercial and industrial sites.  

Within Recap Photo, one can create a new 3D project using either the Aerial or Object functionality. Aerial is used for UAV and drone photos (Where one could have GPS data assigned to the photos) and Object is used for applications other than drones or UAV's.

The process of photo to mesh conversion takes place in 3 stages: Uploading the photos, registering the photos for mesh creation and lastly downloading the 3d model as a .rcm file.  

The end result? If there is enough overlap between the aerial photos you will be able to generate a 3D model with minimal user input. Are you excited? I definitely am!

Toposurface From Infraworks Model - Success!

In the beginning of 2015, I created a post where Infraworks' Model Builder capability was outlined. Since then, we have done numerous tests to see how far the software will get us - 2 Years later, I posted that in Revit 2018 one can link a Coordination Model (Navisworks file) which may be used for site planning. At that time, I could however not find a way of generating a toposurface from the Coordination model.

Enter my colleague Mitchell Parsonage, who managed to create a workflow with three easy steps :

1. Define your site extent in Infraworks and export to an OBJ format

2. Import the OBJ into Autodesk Formit, and Export to DXF

3. Link the DXF into Revit and generate a Toposurface from the Import

4. The end result? Nicely done Mitch!