Request in QGIS ([FEATURE] mesh simplification)

[qgis-bot]

Request for documentation

From pull request qgis/QGIS#34532
Author: @vcloarec
QGIS version: 3.14

[FEATURE] mesh simplification

PR Description:

As mesh layer could have millions of triangles, rendering could be very slow, especially when all the triangles are displayed in the view whereas triangles are too small to be viewed.

For those situations, this PR provides an option to simplify the mesh. Simplification leads to one or more simplified mesh that represents levels of detail. When rendering the mesh, the appropriate level of detail is chosen to have an adequate rendering depending on the view.

A new tab in the mesh layer properties widget allows the user to change the settings :

• The reduction factor is used to simplify mesh, each level of details has approximately a number of triangles equal the number of triangles of the previous level of details divided by the reduction factor
• Maximum mesh resolution: this is the average size (in pixels) of the triangles that is permitted to display, if this average size of the mesh is lesser than this value, a lower level of details mesh is displayed, which will have a average size just greater than the maximum mesh resolution.

This feature permits to speed up rendering as in those tables (result in milliseconds) :

Demo GIF
Before:

After:

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