ExtrudePolygonLayer

ExtrudePolygonLayer is a WebGL 3D extrusion layer of PolygonLayer. It extrudes Polygon / MultiPolygon data into 3D volumes (such as buildings) based on the height property, with the top and side faces rendered with independent materials.

It is a subclass of Vector3DLayer, inheriting all methods of Vector3DLayer and additionally supporting independent top/side materials and extrusion data config.

Constructor

import { ExtrudePolygonLayer } from '@maptalks/gl-layers';

const layer = new ExtrudePolygonLayer('extrude');

Constructor Options

ExtrudePolygonLayer adds the following options on top of the Vector3DLayer options:

Option	Type	Description	Default
dataConfig	Object	The extrusion data config (LitDataConfig); see the default value below	see below
material	Object	The PBR material of the top face (LitMaterial); the default material is used when not set	None
sideMaterial	Object	The side face material; falls back to material when not set	None
cullFace	Boolean	Whether to enable face culling	false
castShadow	Boolean	Whether to cast shadows	true
depthMask	Boolean	The depth writing switch	None

Default dataConfig:

{
  altitudeProperty: 'height',       // 要素属性 height 作为拉伸高度
  minHeightProperty: 'min_height',  // 要素属性 min_height 作为最小高度
  defaultAltitude: 20,              // 无 height 属性时的默认拉伸高度（米）
  perPositionHeight: false
}

That is, the height property of a feature determines the extrusion height, min_height determines the bottom height, and the default extrusion is 20 meters when it is not set.

Methods

updateMaterial(material)

Updates the top face material.

Parameters:

• material Object The PBR material of the top face (LitMaterial); pass null to clear it

Returns:

• ExtrudePolygonLayer this

updateSideMaterial(material)

Updates the side face material; falls back to the top face material when null is passed.

Returns:

• ExtrudePolygonLayer this

updateDataConfig(dataConfig)

Updates the extrusion data config (such as altitudeProperty, defaultAltitude, etc.).

Returns:

• ExtrudePolygonLayer this

Symbol Styles

Symbol properties supported by ExtrudePolygonLayer:

Property	Description	Default
polygonFill	Fill color	[1, 1, 1, 1]
polygonOpacity	Fill opacity	1
topPolygonFill	Top face color	[1, 1, 1, 1]
bottomPolygonFill	Bottom face color	[1, 1, 1, 1]

For special geometries such as Circle, Ellipse, Sector and Rectangle, the layer automatically computes the oriented minimum bounding box (OMBB), converts them to polygons, and then extrudes them.

This document has been cross-checked against the @maptalks/gl-layers 2026 source code (api-notes-vt-gl.md)