Mesh modification

Mesh modifications enable you to remove areas of integrated mesh scene layers and the elevation surface. There are two different ways to remove parts of the integrated mesh layers: by hiding content inside the specified polygons (referred to as clip); or by hiding content outside the specified polygons (referred to as mask). You can add multiple mesh modifications to an ArcGISMeshModificationCollection. Once you have set up the ArcGISMeshModificationCollection with all mesh modifications you want to make, you can set it on an ArcGISIntegratedMeshLayer and ArcGISMapElevation.

Illustration	Modification	Description
	clip removes the specified area	Clip-out areas of integrated mesh scene layers to show other layers or actors in the area. For example, you can place custom buildings and landscapes in the area and combine with spatial data.
	mask displays only content within the specified area	Define an area of interest with a polygon geometry to render only the area of the integrated mesh layer that falls inside the polygon. For example, if you want to show only an area of an integrated mesh within the boundaries of a city.
	replace - flattens selected area	Replace an area of an integrated mesh based on a 3D polygon. For example, to add constructed buildings, flatten the integrated mesh at the footprint of a building so the new building can be visualized. Create different scenarios of the new construction area and share the scenarios as a web scene to discuss with stakeholders. The integrated mesh flattens to the minimum z-vertex of the modification polygon when the polygon is created. You can change the altitude of the area after a polygon is created.

Polygons used to specify the area for mesh modification; must have a spatial reference that matches the spatial reference of the layer or the elevation surface. See When you need to know about spatial references topics to find the spatial reference of your elevation surface or integrated mesh scene layers.

Apply mesh modification to layers

With the Modes Panel UI, you can set mesh modifications for the elevation surface and integrated mesh scene layers. You can use the tool overlay to create polygons and set modifications.

Open the tool overlay in the Viewport

To work with mesh modifications, you need to open the tool overlay in the Viewport.

For the elevation surface:

Click the Elevation tab.
Click the gear icon above the elevation source list to display the tool.

For an integrated mesh scene layer:

Click the Layers tab.
Click the triangle icon on the left to expand the integrated mesh scene layer registry and see the layer properties.
On the Mesh Modifications raw, click the gear icon to display the tool.

Configure a mesh modification

To set a mesh modification, first create a polygon, then set the modification type.

In the tool overlay, click the icon.
Click in the Viewport to draw a polygon.
Click the icon. (The icon color will change to blue.)
Draw a polygon in the Viewport by dropping points with clicks.
Select the polygon by clicking the polygon lines or anywhere inside the polygon. (The line color will change to blue.)
Click the button Clip, Mask, or Replace to select the modification you want to apply.
If you have selected Replace, use the gizmo to set the altitude.
Close the tool overlay by clicking x in the top right corner.

Edit a mesh modification

To edit a mesh modification, open the tool overlay for the elevation surface or the integrated mesh scene layer that has the modification.

Display polygons for the elevation surface or an integrated mesh scene layer by opening the tool overlay.
Select a polygon by clicking the polygon lines or inside of the polygon while the icon is selected in the tool. (The line color changes to blue when selected.)
Deselect a polygon by clicking outside of the polygon in the Viewport.
Use the gizmo to move a polygon while the polygon is selected.
Click a point and drag to move the point position of the polygon.
Add points to a polygon by clicking the middle point of a line.
Copy a polygon by clicking the icon while it is selected.
Paste a polygon by clicking the icon after opening the tool overlay for the elevation surface or an integrated mesh scene layer.
Delete a polygon by clicking the icon while it is selected.
Change the modification type by clicking another button while the polygon is selected.
Uncheck the Mesh modifications checkbox to disable the modification for the elevation surface or the layer.

To create a polygon, use Create ArcGIS Polygon Builder from Spatial Reference node and set the spatial reference with Create ArcGIS Spatial Reference according to your ArcGIS Map's spatial reference. Create a geometry with To Geometry function of the ArcGIS Geometry Builder.
To configure a mesh modification, use Create ArcGIS Mesh Modification node, provide a polygon, and set the modification type, Clip, Mask or Replace.
Register all mesh modifications that you want to apply to a layer or the terrain to ArcGIS Mesh Modification Collection with the Add node.
To apply mesh modifications, use Set Mesh Modifications node for ArcGIS Integrated Mesh Layer or ArcGIS Map Elevation accordingly and provide the ArcGIS Mesh Modification Collection that you want to apply.

Example:

Create a polygon using ArcGISPolygonBuilder with a spatial reference matching the spatial reference of your elevation source or integrated mesh scene layer. When you want to use the polygon for mesh modifications, get the geometry using the ToGeometry method.

Each ArcGISMeshModification requires an ArcGISPolygon and ArcGISMeshModificationType value of Clip, Mask or Replace.

Each integrated mesh scene layer and terrain can have multiple mesh modifications. Put all mesh modifications you want to apply to a specific layer or terrain into ArcGISMeshModificationCollection, then set the ArcGISMeshModificationCollection on the layer. For the terrain, set the mesh modification to the ArcGISMapElevation.

For more information about ArcGISGeometry, visit the Geometry page.