CloudCompare forum

Hi Daniel,

I want to subtract one point cloud from another, and output the difference. I initially thought I would have to bin the points to voxels and then do the subtraction, but it looks as if maybe Cloud Compare will do this. Please, can you confirm whether it will or not, and if so, the steps I might take? I'll be using the results in my Master's project.

Also, I see in another post to the forum that the formulas for CloudCompare are in your dissertation. I have a co-worker down the hallway whose wife is French, and who can also speak and read French. So if it's not a burden, I'd like very much to have a copy.

Many thanks,

Hi,

the manuscript of my PhD (in french) is here: http://pastel.paristech.org/bib/archive/00001745. There's an article in english that gives a good insight of what CloudCompare can do (and how): http://www.danielgm.net/phd/isprs_laser ... 05_dgm.pdf.

And to answer your question: CloudCompare computes distances between clouds (or between a cloud and a mesh), i.e. it computes for each point of a cloud its distance to the nearest point (or triangle) in the other cloud (or mesh). It then displays the resulting differences (distances) on the point cloud (as a 'scalar field'). Various processes can be applied either on the cloud and/or its scalar field (segmentation, etc.). CloudCompare doesn't "substract" anything (I'm not really sure what you meant by this), nor changes the position of points during the process. For directions, you can refer to this post: viewtopic.php?f=9&t=105.

If you have more questions, feel free to ask.

Here is a working link for your thesis manuscript, the other is broken:

http://pastel.enst.fr/1745/01/manuscrit ... tronic.pdf