CloudCompare forum

Hi Daniel,

I have two questions about the calculation of the default input parameters.

1. For the core points, the value doesn't have a unit. What is the unit? The same as my data, meters? Is it a search radius? One core point in each 0.254m radius? Or is it a proportion? For example, 0.254. Can I consider this 25.4% of the full cloud? How is this value chosen?

2. How are these default numbers chosen? I understand that a user may adjust the normal and projection scales (D and d) depending on the heterogeneity of the input data to adjust the sensitivity. So I wonder how these numbers are chosen when I allow defaults.

Thanks in advance!!

Lindsay

1. Yes, it's the minimum distance between two core points (we simply use the 'Subsample" algorithm to select the core points - see http://www.cloudcompare.org/doc/wiki/in ... CSubsample). The units are the same as the clouds.

2. By default it's only very random guesses, based on the size of the clouds bounding-box (like a given percentage). And if you use the 'guess params' buttons, we make some random samplings, and we try to guess better parameters. However it's still approximate and random...

Thanks Daniel!!

Hi Daniel,
I hope you can help me.

I just started to work with CC, and I need a signed distances between comparated clouds.
I have read that it works with a plugin M3C2 but it's not activated.

I don't know how to activate it or to download it. I hope you can help me.

You'll need the Windows version probably (or the latest Linux and MacOS versions maybe).

And of course you'll need at least 2 clouds that you must select in order to enable the plugin.