Diagram showing focal point, principal point and intersecting rays

[foh-/tuh/-*gram*-i-tree] /
–noun: 1. the process of making precise measurements by means of photography.
2. measuring and drawing with light.

Photogrammetry is an incredibly powerful tool for capturing and recording the size, shape and condition of an existing structure. By allowing an architect to create an intelligent “point cloud” & a three dimensional wire frame model of an existing building from photographs off site, this technology provides a safe and economical means to measure and draw even the most complicated structures.

While the most common application of photogrammetry in architectural work is to measure and draw hard-to-access elevations, this technology also provides an excellent way to prepare plan drawings and building sections. By accurately defining the limits of a building envelope, many of the complexities in creating an accurate interior floor plan are resolved. Other deliverables can include elevations of interior spaces and reflected ceiling plans.

See also this blog post.