CloudCompare forum

Hello,
I am new to CC. I have to compare two bed planes against each other and determine the position changes in the vertical direction. Then I must export it into .txt format so that the z-level variations can be plotted against x or y.

I have considered creating a mesh over the plane and comparing meshes. I have also tried cloud to cloud comparisons. These two methods have displayed graphically the changes in two point clouds. However, I haven't been able to export the change into a clear .txt format as yet.

Is this possible? If so, could you kindly give me some advice on how to do it? Thanks for any help.

I'm not sure what you are expecting exactly, but you can convert the active scalar field to any coordinate (e.g. Z) with 'Edit > Scalar fields > Set SF as coordinate(s)'. Then you can delete the scalar field.

From there you can save the resulting cloud as an ASCII file and you'll get 'X, Y, distances' on each line.

Otherwise you may be interested by the Cross Section tool? (In order to display/extract a thin layer along X or Y)

daniel wrote:I'm not sure what you are expecting exactly, but you can convert the active scalar field to any coordinate (e.g. Z) with 'Edit > Scalar fields > Set SF as coordinate(s)'. Then you can delete the scalar field.

From there you can save the resulting cloud as an ASCII file and you'll get 'X, Y, distances' on each line.

Otherwise you may be interested by the Cross Section tool? (In order to display/extract a thin layer along X or Y)

Thank you Daniel for this help. This is indeed a very good software.
To explain myself further, I have attached the scan image that I'm trying to process. This is an image of a flume bed. I have scanned images
after this bed has been altered in some way. Now I want to quantify the change in vertical direction (z-direction) along the bed (the silver colour region on the image).

I followed using cross-section tool but I ended up with too much data that I do not need. If I can confine the variation to one particular region (the bed), it would be easier to interpret. Is there any other way than simply deleting the unnecessary region from the image?

Then you could try the new 'Extract sections' tool:
http://www.cloudcompare.org/doc/wiki/in ... t_Sections (see the 'Generating cloud slices and profiles' section)

After all it is meant to extract profiles along river beds.

P.S.: by the way, to properly compute the vertical distances between your clouds, have you tried the M3C2 plugin? (http://www.cloudcompare.org/doc/wiki/in ... 2_(plugin)). There's a 'Vertical' option in the 'Normals' tab to force purely vertical distances computation.