RenderInstances Interface

Contains the WebGL resources necessary to draw multiple Instances of a GraphicTemplate using instanced rendering. Use createRenderInstances to create one. The instances may be associated with Features, in which case those features override any defined in the template itself. Example usage:

/** Create a graphic that renders multiple instances of a glTF model. */
export async function instanceGltfModel(gltf: Uint8Array | object, positions: Point3d[], iModel: IModelConnection): Promise<RenderGraphic> {
  // Decode the raw glTF as an instanceable  template.
  const template = (await readGltfTemplate({ gltf, iModel }))?.template;
  if (!template) {
    throw new Error("Failed to decode glTF model.");
  }

  // Generate an Id for a "model" to contain the instances.
  const modelId = iModel.transientIds.getNext();

  // Define multiple instances, one at each of the specified positions.
  const instancesBuilder = RenderInstancesParamsBuilder.create({ modelId });
  for (const position of positions) {
    instancesBuilder.add({
      // Translate to the specified position.
      transform: Transform.createTranslation(position),
      // Assign a unique pickable Id.
      feature: iModel.transientIds.getNext(),
    });
  }

  const instancesParams = instancesBuilder.finish();
  const instances = IModelApp.renderSystem.createRenderInstances(instancesParams);

  // Create a graphic that associates the instances with the template.
  return IModelApp.renderSystem.createGraphicFromTemplate({ template, instances });
}

Defined in

• 65/itwinjs-core/core/frontend/src/render/RenderSystem.ts Line 235