close an open shape (point cloud) by creating/fitting a plane to measure volume

[h.shayan]

Dear CC community,

My question is how to close an open shape (point cloud) by creating/fitting a plane to measure the actual volume, not 2.5D volume, in this case the volume of an iceberg above water. We used photogrammetry method to make a point cloud in Agisoft. To reach this, I did the followings,

1) Create point cloud in Agisoft and export .ply format to CC (Fig.1)
2) Reduce noise and create Poisson Surface Reconstruction (Dirichlet boundary) (Fig.2)
3) Remove the bottom part of the object (this part results to have an open object at the bottom) (Fig.3 and Fig.4)
4) Making sample points on the surface as a new point cloud. Fig.5 show that the object is open at the bottom.

As I want to measure the actual volume, I need to close the shape at the bottom. For this I made a code in MATLAB to fit the plane at the bottom of the point cloud, and then export that “closed point cloud” to CC to create Poisson Surface Reconstruction (Fig.6) with free boundary. Then I can measure the volume for this object.

My question is: How I can create the plane in CC rather than in MATLAB? Is there a plugin, function or process for that? Fitting the plane in MATLAB is time consuming and depending on the geometry it may not be correct. I am sure I should be able to do this in CC, but I don’t know how.

Thank you in advance for your help and support.

[daniel]

Something like 'Tools > Fit > Plane'?

You would have to segment or pick a few points on the border of the 'hole' first.

[h.shayan]

Thank you Daniel.

That seems a good idea. But in the end, I want to define new points on the plane to close the shape. Please see attached figures (the pictures for a new iceberg, not the one that I sent in the previous post). The red points show the profile of the iceberg at the waterline from the top view. I added the blue points in the polygon (red points) to close the point cloud at the waterline surface.

Do you have any idea how I can do something similar in CC?

Once again thank you so much for your help.

[daniel]

Yes sorry, I wanted to say 'Edit > Fit > Facet'. It's more or less what you represented.