CloudCompare forum

Hi everyone,
I'm new here and with Cloud Compare. Thanks for what seems to be a great open software (I hope I'll manage to master it a little bit...).
Maybe this question has already been asked, but I didn't find the info easily, so I apologize if it's already written or explained somewhere... Here's my problem: I have a huge point cloud (it's a mansion with 5 levels, we had to do 210 scans to have the entire building) that is 53 GB (after exporting it in .e57) and want to import it in ArchiCAD for my client but ArchiCAD cannot support point clouds that weigh more than 4 GB. I even couldn't open the file in CC since it is to heavy (I think). I though I could import point clouds of each level of the mansion, but my point cloud of one level is still too heavy (14 GB ; I can open it in CC). Is it possible to reduce the size of a point cloud in CC and if yes, what are the steps?
I also read that they are bugs with importing point clouds that are in greyscale in ArchiCAD. The solution was to "optimized the greyscale" point cloud in CC : where shall I find this command?
Thank you very much in advance for you advises and replies,
I'll watch some tutorials to, in order to get to know better this software, and avoid obvious questions here ;) (hope these ones are not so obvious... if so, I'm verry sorry).
Kind regards

Indeed, not sure how many points 53Gb correspond to, but there are probably two many points to handle at once for CC (we have a theoretical limit of 2 billion points per cloud). And of course you'll need a lot of memory.

So it's good if you manage to open the 14Gb files...

Then yes, you can 'subsample' a cloud (with 'Edit > Subsample' - see https://www.cloudcompare.org/doc/wiki/i ... CSubsample). The best method is probably the 'space' decimation (that ensure the points are regularly sampled), but with a huge point cloud it may be challenging, so you may prefer the 'random' one, which is much faster and doesn't need additional memory.

And to make things even easier for CC and your computer, you can apply this algorithm via the command line mode (see https://www.cloudcompare.org/doc/wiki/i ... _line_mode - with the -SS option).

And to 'optimize' the gray scale, I'm not sure but I guess it's a matter of changing the range or the scale of the intensity values? Maybe with the 'SF Arithmetics' tool? (or the -SF_ARITHMETIC option with the command line mode)

daniel wrote: ↑Thu Jun 03, 2021 7:24 pm Indeed, not sure how many points 53Gb correspond to, but there are probably two many points to handle at once for CC (we have a theoretical limit of 2 billion points per cloud). And of course you'll need a lot of memory.

So it's good if you manage to open the 14Gb files...

Then yes, you can 'subsample' a cloud (with 'Edit > Subsample' - see https://www.cloudcompare.org/doc/wiki/i ... CSubsample). The best method is probably the 'space' decimation (that ensure the points are regularly sampled), but with a huge point cloud it may be challenging, so you may prefer the 'random' one, which is much faster and doesn't need additional memory.

And to make things even easier for CC and your computer, you can apply this algorithm via the command line mode (see https://www.cloudcompare.org/doc/wiki/i ... _line_mode - with the -SS option).

And to 'optimize' the gray scale, I'm not sure but I guess it's a matter of changing the range or the scale of the intensity values? Maybe with the 'SF Arithmetics' tool? (or the -SF_ARITHMETIC option with the command line mode)

Thank you very much. The subsample technique worked and I managed to reduce my file to 2 GB. Still I cannot see it (it loads but doesn't appears) on ArchiCAD but that's another problem...
About the gray scale, here's the forum where I saw this technique ("optimise" and "gray scale", it's in French, look at the "resolved" reply) on cloud compare which I didn't understand : https://www.archi-cadlink.fr/viewtopic.php?t=1178
Thanks again for your reply :) it helped eventhough I still cannot open it in ArchiCAD !

What is the difference between the Subsample and Clean tools and why would you choose the former for this task?

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I don't know much about CC but afaik, subsampling is one way of making a pointcloud smaller and easier to manage with Archicad for example, by reducing the density of points. 3D Laser scaners are able to capture millions of points, but if you're just scanning a small bathroom, you dont need 50 million points for it, it's enough to bring down the density.

Cleaning the pointcloud is also another way of making it smaller, but this tool rather use more sophisticated algorithms to check for "noise" in the pointcloud and deleting them. If you're scanning a bathroom them most surely if there's any wavy shape in the pointcloud it could rather be noise, while leaving the pointclouds that form planar shapes almost untouched.

The cleaning tool usually uses more computing power than subsampling so the subsampler is easier to use. Also with removing noise you may end up with not very satisfying results (perhaps the noise remover deleted the toilet).

As always, the best way to see if that you use both methods and see what's best for you.

Personally for Archicad I use subsample by distance of 3cm and that's more than enough.

And Blondy, feel free to send me a PM if you still haven't been able to open the pointcloud in Archicad.