Cross Section and contour from mesh

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Ingsayyad
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Joined: Fri Oct 25, 2013 9:17 am

Cross Section and contour from mesh

Post by Ingsayyad »

I have mesh and wanted to have contours of it (z=21-31 m @10 cm).
My thoughts are to make cross Section, convert each cross Section to sample points and get contour of it. (I don't know the better workflow or direct solution). Now my problem is what values I need to set in Cross Section dialogue to get cross sections that start with 21 m and end 31 m @10 cm interval.
Any help?
I myself always end up with random start value of cross section with 10 cm interval.
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daniel
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Re: Cross Section and contour from mesh

Post by daniel »

If you want to use the 'Repeat slice dialog' in the way you intend to, you should first define the limits of the first clipping box accurately.

To do this you should click on the 'advanced' button (below the 'box thickness' frame).

Your first slice should be at z = 21 m exactly (for the bottom part) and with a width of 10 cm (use the box thickness 'Z' field). Once ready you can start the 'repetitive slicing tool' (along Z). You might get more slices than you expect (if the cloud goes below 21 m and above 31 m) but either you discard those slices afterwards, or you crop your cloud first).
Daniel, CloudCompare admin
daniel
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Re: Cross Section and contour from mesh

Post by daniel »

Oh, and if your mesh is 2.5D, you should definitely consider using the 'Rasterize' tool (which can extract contour lines - see http://www.cloudcompare.org/doc/wiki/in ... =Rasterize)
Daniel, CloudCompare admin
brcuenca
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Re: Cross Section and contour from mesh

Post by brcuenca »

Regarding cross section tool, I'm having some problems with contour option using command line.
I want to run the contour tool in order to extract contours of a point cloud and save them as polilines, but I just can get slices of my cloud. Is there any option to extract contours using command line (or are there any setting about contour option to include in the .xml file that is not detailed in cross_section_params.xml)?

Thanks in advance
daniel
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Re: Cross Section and contour from mesh

Post by daniel »

Hi believe that indeed the command line version of the cross section tool only generates the cloud sections (and not the polyline). It has been developed by a company for its own needs (and therefore they didn't need the polylines ;).

Therefore the code should be modified if you want to extract polylines.
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snfge
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Joined: Thu Nov 20, 2014 4:12 am

Re: Cross Section and contour from mesh

Post by snfge »

Hi
When I use the Cross Section , but the Extract contours can't be choose, why?
daniel
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Re: Cross Section and contour from mesh

Post by daniel »

The section extraction tool only works on clouds.

And while you can use the Cross section tool on meshes, it's only to slice them (you can't extract contour lines).

Only the new 'Trace polyline' tool can extract (partial) contour lines on meshes.
Daniel, CloudCompare admin
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