2,5D Volume Interpolation Method

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Danny64
Posts: 2
Joined: Thu Jul 08, 2021 6:16 pm

2,5D Volume Interpolation Method

Post by Danny64 »

Cheers Fellows,

I`m a new User of this great Software. I learned a lot in this Forum and i will keep going with searching for answers in here.
Also, thank u Daniel for all ur helpfull answers. Now i wanna come up with a short question for an explanational answer, related to the given interpolation method in the tool "2,5 D Volume".

Like, i m interested to know in which way does the tool calculate a height value for an empty cell?
Does it use the `linear" or the `natural neighbours`method? For my project, i m simply comparing the results after interpolation of a small scaned area.

I m realy glad to be handling with this nicely working Software


Everyone have a good day

Danny
DA523
Posts: 166
Joined: Mon May 25, 2020 4:02 pm

Re: 2,5D Volume Interpolation Method

Post by DA523 »

According to my experience,
"Interpolation" leads to wrong volume in some cases (shape projection is convex not concave and other cases)
"leave it empty" is the best method but require dense points which easily we can work around with 3D software

I attached example to show (if I am not wrong ) where interpolation fails to calculate volume of shell against flat plane .
Attachments
Group.7z
(1.75 MiB) Downloaded 293 times
DA523
Posts: 166
Joined: Mon May 25, 2020 4:02 pm

Re: 2,5D Volume Interpolation Method

Post by DA523 »

Another example showing when "Interpolation" fails
while "leave it empty" success after using sub-sample 100k points of mesh
-
see attached
volume.zip
(1.86 MiB) Downloaded 508 times
daniel
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Location: Grenoble, France
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Re: 2,5D Volume Interpolation Method

Post by daniel »

Interpolation is done by 2.5D triangulation (Delaunay triangulation exactly). So it's a kind of linear interpolation between the 3 closest neighbors.

But it is indeed done in the convex hull of the points, which might lead to either missing parts, or on the contrary fake points.
Daniel, CloudCompare admin
Danny64
Posts: 2
Joined: Thu Jul 08, 2021 6:16 pm

Re: 2,5D Volume Interpolation Method

Post by Danny64 »

Thanks a lot DA523 & daniel !! Appriciate it... And soon i'm looking more into it. As of now u helped me lot.

kindly regards
Danny
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