CloudCompare forum

Hello,

I am looking for a workflow how to calculate volume between point cloud (excavation site) and a mesh (BIM model). We have a scanned excavation site and a building is to be build inside it and we are looking to calculate how much concrete will be required to pour between walls of the excavation site and building. It is not a simple cut and fill stockpile volume calculation and I cant seem to find a workflow that would correctly calculate this, as it is kind of complicated geometry and the distance between wall of building and point cloud is really low. I dont know if such calculation is even possible in CloudCompare and any advice for how to solve this even using other software is appreciated.

I hope I expressed myself clear enough and to help that Im also providing a video to demonstrate my problem. I can also provide the point cloud and the mesh.

https://www.youtube.com/watch?v=xylneY0GMa8

Im using CloudCompare v2.12.4 Kyiv Windows 10 64 bit

Thank you

It still looks like a 2.5D problem? I guess the '2.5D Volume calculation tool' could work. The main challenge is probably to convert both entities to dense clouds without holes...

Can you send me the data to admin@cloudcompare.org maybe?

Hi Daniel,
sent you the mesh and cloud in email.

We have acctualy managed to calculate the volume with help of other software – the easy way. I just cut the cloud with plane where the wall of the mesh (building) should be, the software created mesh above the plane and calculated the volume of the mesh. I’m not quite sure I understand the 2,5D Volume calculation and how similar and different it is to the plane cut technique. If you would be so kind to record a quick video of how you would calculate the volume of one of the walls, it would be not only helpful for me to validate my other results from the other software, but for anyone reading with a similar problem.

Martin

Ah, sorry I missed the part about the 'walls' ... so you would need to have a mesh that only delineates the top of the walls (section). Then sample points on this mesh (you would only have points at the very top, and only where the points will be).

Then you also have to mesh the point cloud (ground) so as to fill the holes. This can be done with PoissonReconstruction. But this may be even simpler to create 3 planes that represent the 3 flat horizontal surfaces. Then once again, sample points on these 3 planes.

Eventually, you can 'compare' the 2 clouds (the top section of the walls, and the ground (planes) with the 2.5D Volume calculation. It will give you the volume between the 2.

I couldn't make a video because tinkering with the OBJ mesh to extract only the top of the wall was hard (and not easy with CC). A very approximate result gives me something around 81.2 m^3 (assuming the cloud units were meters).

Hi,
I'm not quite sure I follow and not quite sure we are on the same page. It seem you have calculated somehow the volume of the "whole thing", I think you need to isolate each wall. My calculations are much more conservative with around 2 m^3 for each wall.

What I need is something like this: https://imgur.com/a/Ct1vK8j where the planes are the walls of the building and need to get volume between the walls of the building (planes) and the excavation (scan).

Here is another video https://www.youtube.com/watch?v=H76e-xA6LLE where I isolate one of the walls with planes that I sampled like you said (ground,top) and I think you also need to sample the vertical (building) wall? My idea is it should work like this ? (option 1 or option 2): https://imgur.com/a/AnfoEUh

It is hard to put this problem into words, but I hope we are on the right direction. Once again, I can send you the CC file with the planes, sampled planes etc, so you dont have to do it manually.

Thank you for your time,
Martin

Si I really computed the volume of the colored parts indeed (so the 6 straight sections, with a constant thickness, and considering only the 'height' above the ground).

From what I understand, you only want to know a part of this volume, which extents are a little bit tricky to define ;). Not sure how I or CloudCompare can help you further...

Thank you for your time :)!

Hi Martin, I have the same problem as you described. Can you share what program you used to calculate the volume?

Hello,
sorry for a late reply. We have used FARO BuildIT. I hope it is not against the rules to share other software.

Martin

No problem, CloudCompare is not a commercial solution, so we don't really consider other solutions as 'competition' ;)