Definition of center-points of 2D Polygons (facet)

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Michael123
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Joined: Wed Aug 26, 2020 1:51 pm

Definition of center-points of 2D Polygons (facet)

Post by Michael123 »

Hello,

I generated different cross-sections along a cave-system with the segmentation tool and recieved different polylines. Based on those polylines I created surfaces by using the fit--> 2D Polygon (facet) Algorithm. For each surface the software calculates a center point and shows the coordinates of that point. My question is how CC determines these center points?
At the beginning I thought this point represents the center of mass of the geometry and this seemed plausible in some cases, at least by optical evaluation. But in some cases this point did not seem to be a real center point. I attached an image with one of those bad results (center point in "red").

I hope you can help me out.
Best regards
Michael
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Crosssection_Center-Point.PNG
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daniel
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Re: Definition of center-points of 2D Polygons (facet)

Post by daniel »

The 'center' of a facet entity is indeed the barycenter of the input points that were used to create it. Therefore it might be different than the barycenter of the contour points (there might be more points used to create the facet).

If you want to know where the barycenter of the contour is, you can select the polyline vertices (below the contour polyline entity in the DB tree) and use the 'Edit > Batch export > Export cloud info' tool (it will create a file with some various info).
Daniel, CloudCompare admin
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