Core ML - captureOutput can capture 3D object but can it provide x, y position?

I can use the caputreOutput to identify the 3d object, but I do not know how to get the x, y position of the corresponding object.

Can anybody help?

I can idenity the object by .identifier but as the time I use .accessibilityActivationPoint.x and .accessibilityActivationPoint.y to detect the x, y position. (Please see the code below) It always come out as 0. And even I move closer or farther the object. The results are always 0.

How can I detect the x, y position of the captured object?

Thanks

func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {

// print ("Camera was able to capture a frame:", Date())

guard let pixelBuffer: CVPixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else {return}

guard let model = try? VNCoreMLModel (for: CubeImageClassifier().model) else

{ return }

let request = VNCoreMLRequest(model:model)

{

(finishedReq,err) in

guard let results = finishedReq.results as?

[VNClassificationObservation] else {return}

guard let firstObservation = results.first else {return}

if firstObservation.identifier == "Cube" {

print("It is a Cube. Conference = \(firstObservation.confidence)")

print("Pos-x=\(firstObservation.accessibilityActivationPoint.x)")

print("Pos-y=\(firstObservation.accessibilityActivationPoint.y)")

}

else { print("NOT Cube")}

}

try? VNImageRequestHandler(cvPixelBuffer: pixelBuffer, options: [:]).perform([request])

}