There is no limit to the size of part, the only thing is that the coded targets must be visible on the photo and "readable", or you can "pick" manually the points.
If you can print and place large coded targets, and if the black center circle of the target has a diameter of more than 6 pixels on the photo, Pixdim can reconstruct the 3D scene.

We have made successful reconstruction with parts measuring 25.00 meters x 15 meters.