Force mesh by polylines (Request in QGIS)

[qgis-bot]

Request for documentation

From pull request qgis/QGIS#44962
Author: @vcloarec
QGIS version: 3.22

Force mesh by polylines

PR Description:

In the scope of mesh editing, this PR allows the user to force the mesh by existing polylines (as break lines). Forcing lines consist of line that the faces are forced to follow, that is edges of encountered faces have to be on theses lines.

The user choose vector layers geometries in the map canvas by selecting them. Then, the user clicks on the dedicated push button to force the mesh on the lines contains by these geometries.

The different options are:

• add new vertices when the lines cut the internal edges
• interpolate the Z value of new added vertices on the mesh or from the lines
• Tolerance : when a lines is at a distance from an existing vertex lower than the tolerance, no new vertex is created but the existing vertex is used

Note about the terminology:
These type of lines can be called break lines. The word "force" is use here because, usually, especially when TIN are constructed, break lines are permanent lines that will be used even later for new faces operations (add, remove flip, ..) to continue to constrained the mesh. In that case, break lines are part on the mesh data, and are identified as this. Here, we just apply this "forcing" line and leave, so for latter operation, the faces are not constrained anymore, as opposite as real break line. Maybe later we could have some real break lines that will permanent in mesh layer, so it is important to differentiate the terminology today.

Commits tagged with [need-docs] or [FEATURE]