## General

The tool ResetPropertiesInPolygonalRegion changes the property values of all elements of a mesh mesh in which at least one node of the element lies within the cylindrical volume defined through a given polygon polygon_name within the geometry geometry to a new value.

The new value must be of one of the data types, either integer {1, 2, 3, …} (new_int_value), character {‘a’, ‘b’, ‘c’, …} (new_character_value), or boolean {true,false} (new_boolean_value). The new value must fit the chosen property type of name_of_property.

The polygon must be located within a plane. A node is located in the cylindrical volume iff (i.e. if and only if) the node’s orthogonal projection to the plane of the polygon lies in the polygon, i.e. the plane can be defined in any arbitrary direction in 3d space.

In combination with a threshold filter the tool can also be used to cut out some region of the mesh. The tool can be also used in combination with the tool removeMeshElements.

The tool writes a new mesh modified_mesh.

## Usage

ResetPropertiesInPolygonalRegion
-m [mesh]
-r [MaterialID]
-n [name_of_property, default MaterialIDs]
-i [new_int_value, optional]
-c [new_character_value, optional]
-b [new_boolean_value, optional]
-g [geometry]
-p [polygon_name]
--any_of
-o [modified_mesh.vtu]

By default all nodes of an element have to be inside the polygon to set the property on the element. By specifying the boolean switch any_of at the command line the criterion for element selection changes to ‘at least one node has to be inside the polygon’.

## Examples

### First Example

Example usage:

ResetPropertiesInPolygonalRegion
-m TestCube.vtu
-n ValidCells
-c B
-g TestPolylines.gml
-p Back
-o TestCube-BackPolylinePropertyChange.vtu

Creates a new property “ValidCells” and sets the value for the property of elements in the polygonal region “Back” to “B”.

### Second Example

ResetPropertiesInPolygonalRegion
-m hex_5x5x5.vtu
-g Regions.gml
-p Region1
-n MaterialIDs
-i 11
-r 2
-o hex_5x5x5_Region1-Layer1.vtu

Here the elements with the material ID of 11 are displayed non-transparent.

The final mesh containing 12 material groups is represented in the right figure and was created by the command

ResetPropertiesInPolygonalRegion
-m hex_5x5x5_Region1-Layer2.vtu
-g Regions.gml
-p Region2
-n MaterialIDs
-i 12
-r 5
-o hex_5x5x5_Region1-Layer2_Region2-Layer5.vtu

Again, the elements that are assigned to the new material group 12 are displayed non-transparent.

Download links for the files necessary to reproduce this example are at the end of this site.

## Application

This workflow was successful used in the INFLUINS project cutting out the Unstrut catchment from a 3d geological structure model:

Fischer, T. and Naumov, D. and Sattler, S. and Kolditz, O. and Walther, M. (2015): GO2OGS 1.0: a versatile workflow to integrate complex geological information with fault data into numerical simulation models. Geosci. Model Dev., vol. 8, p. 3681--3694, DOI:10.5194/gmd-8-3681-2015 https://www.geosci-model-dev.net/8/3681/2015/gmd-8-3681-2015.pdf

### Example Files

This article was written by Thomas Fischer. If you are missing something or you find an error please let us know.
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