Measurement

Photo4D can compute the distance and the middle location between two points. This is done by selecting the Measure page of the Main Window, which sets Photo4D to the Modeling mode.

The basic steps for measurement are:

1. Select a measurement type by pressing one of the option buttons:
   • dist(p1,p2): The distance between point p1 and p2.
   • (p1+p2)/2: The mid-point between point p1 and p2.
   • (p1+p2)/3: Divides the distance between p1 and p2 into thirds and determines the point which is closest to p1.
2. Select a point (p1) in the Image window where you want to take the measurement, by clicking the shift-left button on a mark.
3. Select point p2 the same way (click shift-left button on a mark). Both points become highlighted in green and the result of the measurement is displayed in the list box.
4. Repeat steps 3 and 4 to take other measurements. Each measurement will be displayed in the listbox.

The measurement feature is useful for constructing geometrical primitives. For example, to construct a sphere, users can mark two points on the opposite side of the sphere, and then use the measurement feature to get the diameter and center location of the sphere.