CloudCompare forum

I have a randomly oriented (rough) surface, which I want to rotated into the x-y-plane. As I saw there are two options in CC:

1. Use the Tool Fit->Plane and edit the surface by "Apply Transformation" where it is possible to paste the matrix calculated before.
2. Use RANSAC to find the fitting plane and then use the tool "Pick three points to make a cloud or mesh 'level'" on the left column.

Is there any difference in the result? (Tried it once by chance and there was no difference) What RANSAC does is well documented, because the published paper is cited, but do anybody know how CC calculates the transformation vector in the first possibility? Principle Component Analysis (PCA)?

Would be nice to have there some more information, can't find it on wiki!

Thanks! Holg

Indeed the first method uses PCA. The main difference with Ransac is how the points are selected. In the first case you use all the points, while in the other a subset is randomly selected

And mind that you can use the Level tool on any cloud ( you don't need to call Ransac or anything. Level only uses the 3 picked points.

Thanks a lot for your response! It answered my questions...Cheers, Holg