Hi Francesco,

do you have some minimal sample, where these pyramids are created?

It looks to me like a bug and I should investigate this issue. Normally - only a 3D envelope of splay shots from each station should be created. Splays from other stations should not be taken into consideration.

Thanks, S.

On Sun, 20 Feb 2022 at 23:07, Francesco Serafin <francesco.serafin2@gmail.com> wrote:
Hi,

Thank you for the very useful "volume statistics" tool!

I was wondering: how is the volume computed in Loch?

Looking at Loch-generated models in Paraview, it seems to me that Loch creates the volumes by joining every station to the splays radiating from the previous and next stations, creating a sequence of pyramid-like solids, like in this schematics:
image.png
(black=centreline shots, dashed grey=splay shots).
Does each of these "pyramids" contribute to the total with its own volume?
With this method, the mesh would contain intersecting volumes. To simplify, if we imagine a cone with apex at the stations, the cones intersect:
image.png
How does the computation of the total volume deal with the intersections of the cones?
Does it somehow avoid the double-counting coming from the intersecting regions?

Thank you,
Best,
Francesco



On Sun, Feb 20, 2022 at 4:08 PM Tarquin Wilton-Jones via Therion <therion@speleo.sk> wrote:
"added support for cave volume calculation (Tools → Survey statistics)"

Awesome addition.

Could someone maybe explain what the difference is between 3D and LRUD envelope?
I get how 3D probably works based on the rendered 3D view of the cave.  But how can the LRUD thing work when I only use splays instead of LRUD? Does it just pick some particular or average splay and use it as a LRUD measurement? The results are so vastly different. Sometimes much bigger (one of my simple caves) sometimes much smaller ( a pothole).

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