Pix4Dmapper 3D Terrain Areas

I have a question about “Volumes” in pix4Dmapper.

When calculate a volume, there is a “Terrain 3D Area” also calculated.

In the manual, the definition is as shown below:
“Terrain 3D Area [units2]: Area that is defined by the DSM included in the volume’s base.”

Does anyboy know how pix4Dmapper calculates the terrain 3D area?

Thanks in advance!

Hello @wdh91, When you do a volume measurement, you will first draw a surface (base polygon). The 3D Surface Area is the area of your DSM within the base polygon.