Strutt|Propagation|Conformal Area provides the correction for a conformal area, given the length, width, height and distance in metres from the source.
The image below illustrates that a conformal area has rounded corners, which will result in the conformal area calculation becoming equivalent to a point source calculation for large distances.
This is implemented as:
`x = 10log_10(S)`, where
`S=(A+B)(2C+pi r)+2 pi r(C+r)+(AB)`
Note that this calculation assumes the source is located on a reflective surface; at large dimensions the results from this calculation converge to the same as hemispherical distance attenuation: Spherical Correction.