My second sample project using photographs to create dense point clouds to describe a non orthogonal object used a column base from the cathedral de Saint Pierre de Geneve. These stone surfaces proved to be easier to capture than the sleek, reflective brass surfaces o the sculpture in my previous post.
This point cloud was created with a series of a half dozen photographs shot in an arc from left to right around the subject matter. We can see here that in oreder to get all of the surfaces adequately rendered, one needs to also change the height of the camera’s point of view.
As it is, the point cloud consists of over 15,000 points. The points can be imported directly into AutoCAD with their true colors and manipulated there to be transformed into a surface model – or simply as the basis for a measured line drawing. As for accuracy, 75% of the point measurements (which would include virtually all of the measurements describing the subject close at hand) are accurate to less than 1/8″. Half of them are more accurate than 1/16″.
Here is a photograph of the column base, followed by two more views of the point cloud: