The measurement tools for 3D content allow you to measure length and area from high resolution, up-to-date 3D textured mesh. Viewing and measuring 3D content do not count towards your standard imagery data allowance.
Measuring 3D content
The greatest source of error when measuring distances less than approximately three km is your ability to select the start and end points correctly.
The 3D scene has the following spatial accuracy specifications: Horizontal - 11" or 28cm RMSEr, Vertical - 16" or 40cm RMSEz.
Assuming an object is well-constructed as described above and the correct start and endpoint for a desired measurement can be chosen, measurement should be within 40cm.
Which measurement is more accurate, 3D or Oblique?
Actual measured accuracy is determined by how well the endpoints of the measurement can be seen and how well the tool is used to place the start and endpoints. This can be affected by zoom level, perspective, and any obstructions. With practice behavior becomes more consistent, and in tests of measuring with both 3D and oblique images, results are consistently within about 1 meter of each other.