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GeometryInstance

GeometryInstance

new

Geometry instancing allows one Geometry object to be positions in several different locations and colored uniquely. For example, one BoxGeometry can be instanced several times, each with a different modelMatrix to change its position, rotation, and scale.

Parameters:
Name Type Argument Default Description
options.geometry Geometry The geometry to instance.
options.modelMatrix Matrix4 <optional>
 Matrix4.IDENTITY The model matrix that transforms to transform the geometry from model to world coordinates.
options.id Object <optional>
 undefined A user-defined object to return when the instance is picked with Scene#pick or get/set per-instance attributes with Primitive#getGeometryInstanceAttributes.
options.attributes Object <optional>
 Per-instance attributes like a show or color attribute shown in the example below.
Throws:
DeveloperError : options.geometry is required.
Example
// Create geometry for a box, and two instances that refer to it.
// One instance positions the box on the bottom and colored aqua.
// The other instance positions the box on the top and color white.
var geometry = new BoxGeometry({
  vertexFormat : VertexFormat.POSITION_AND_NORMAL,
  dimensions : new Cartesian3(1000000.0, 1000000.0, 500000.0)
}),
var instanceBottom = new GeometryInstance({
  geometry : geometry,
  modelMatrix : Matrix4.multiplyByTranslation(Transforms.eastNorthUpToFixedFrame(
    ellipsoid.cartographicToCartesian(Cartographic.fromDegrees(-75.59777, 40.03883))), new Cartesian3(0.0, 0.0, 1000000.0)),
  attributes : {
    color : new ColorGeometryInstanceAttribute(Color.AQUA)
  }
  id : 'bottom'
});
var instanceTop = new GeometryInstance({
  geometry : geometry,
  modelMatrix : Matrix4.multiplyByTranslation(Transforms.eastNorthUpToFixedFrame(
    ellipsoid.cartographicToCartesian(Cartographic.fromDegrees(-75.59777, 40.03883))), new Cartesian3(0.0, 0.0, 3000000.0)),
  attributes : {
    color : new ColorGeometryInstanceAttribute(Color.AQUA)
  }
  id : 'top'
});
See:
Source:

Members

:Object

Per-instance attributes like ColorGeometryInstanceAttribute or ShowGeometryInstanceAttribute. Geometry attributes varying per vertex; these attributes are constant for the entire instance.
Default Value:
  • undefined

:Geometry

The geometry being instanced.
Default Value:
  • undefined

:Object

User-defined object returned when the instance is picked or used to get/set per-instance attributes.
Default Value:
  • undefined
See:
  • Scene#pick
  • Primitive#getGeometryInstanceAttributes

:Matrix4

The 4x4 transformation matrix that transforms the geometry from model to world coordinates. When this is the identity matrix, the geometry is drawn in world coordinates, i.e., Earth's WGS84 coordinates. Local reference frames can be used by providing a different transformation matrix, like that returned by Transforms.eastNorthUpToFixedFrame.
Default Value:
  • Matrix4.IDENTITY