Mesh modification

Mesh modifications enable you to remove areas of integrated mesh scene layers and the elevation surface. There are two ways to remove these: by hiding content inside specified polygons (referred to as clip), or by hiding content outside 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, ArcGISMapElevation, or an ArcGISOGC3DTilesLayer.

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 content only 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 within the polygon. For example, if you want to show only an area of an integrated mesh inside the boundaries of a city.
	replace - flattens the 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 to visualize the new building. Or save different scenarios of a new construction area as a web scene that replaces the integrated mesh at that site. 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 the When you need to know about spatial references topics to find the spatial reference of your elevation surface or supported data 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, open the tool overlay in the Viewport.

For the elevation surface:

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

For an integrated mesh scene layer:

Click the Layers tab.
Click the triangle button on the left to expand the integrated mesh scene layer registry and see the layer properties.
On the Mesh Modifications raw, click the gear button 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 button.
Click in the Viewport to draw a polygon.
Click the button. (The button 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 Clip, Mask, or Replace button to select the modification you want to apply.
If you selected Replace, use the gizmo to set the altitude.
Click x in the top right corner to close the tool overlay.

Edit a mesh modification

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

To display polygons for the elevation surface or an integrated mesh scene layer, open the tool overlay.
To select a polygon, click the polygon lines or click inside the polygon while the button is selected in the tool. (The line color changes to blue when selected.)
To deselect a polygon, click outside of the polygon in the Viewport.
To move a polygon, use the gizmo while the polygon is selected.
To move the point position of a polygon, click a point and drag.
To add points to a polygon, click the middle point of a line.
To copy a polygon, click the button while the polygon is selected.
To paste a polygon, click the button after opening the tool overlay for the elevation surface or an integrated mesh scene layer.
To delete a polygon, click the button while the polygon is selected.
To change the modification type, click another button while the polygon is selected.
To turn off modifications for the elevation surface or the layer, uncheck the Mesh modifications checkbox.

To create a polygon, use the 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 the To Geometry function of the ArcGIS Geometry Builder.
To configure a mesh modification, use the 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 the mesh modifications you want to apply to a specific layer or terrain into an 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.