Interactive 3D Surface Plot - extracting underlying information possible?

Hi,

I am looking for a convenient and fast way to extract the dimensions of 3D structures (2D projection is sufficient). Thresholding folllowed by particle analysis fails in 20-30% since the objects sometimes are hollow. Visually I get a good and extremely fast representation of what I want to see using the Interactive 3D Surface Plot plugin in Fiji with certain smoothing and threshold. Is it possible to extract the information which is visualized with isolines/dots from the plugin in a numeric format? Sorry if this question is entirely stupid.

Thank you in advance for any input.
Jenny