CloudCompare forum

Hi there,
I’m experiencing some issues trying to segment a mesh with the scissors tool. I can always get the meshes properly segmented. However, their respective vertices are not segmented in the same way. Invariably, the vertices of the ‘remaining mesh’ are not segmented at all. I would like to segment both mesh and its vertices into two in only one cut so there are either no overlaps or missing patches between them. I tried selecting only the meshes or meshes+vertices and it doesn’t seem to make any difference. Is there any option I’m forgetting to select?
Thanks a lot.

In fact this is a limitation of the underlying segmentation algorithm. To reduce (peak) memory and to save a bit of time (and sweat for the developer ;) the set of vertices of the original mesh is not modified (we only strip some of its triangles out).

One trick to achieve what you are trying to do is:

• perform the initial segmentation with the scissors tool
• with CTRL key pushed, select both the vertices and the mesh entities of the 'ugly' part in the DB tree
• Open the 'cloud/mesh' distances computation tool dialog ("Tools > Distances > Cloud/Mesh dist.")
• Uncheck the 'signed distances' checkbox then click on the red 'Compute' button
• Once finished (it may take a while as this is a particularly unfavorable case ;) close the dialog and select the ugly mesh only. Then segment it based on its distance values (with 'Edit > Scalar Fields > Filter by value') keeping only points with zero values (Min = Max = 0 - this corresponds to the vertices actually used by the mesh structure). This way you should get a 'clean' version.