Filter out vertex buffer by classification?

I have some code that was mostly taken from an open source project on github.

I am trying to export an ARkit mesh into a 3d usd file, and this is currently working great.

However I want to remove all the vertices that are not on walls or windows, giving me a 3d usd file with ONLY walls and windows.

Code Block swift
 // Transform the vertex buffer into an array of points
  func transformedVertexBuffer(_ transform: simd_float4x4) -> ([Float], Int) {
    var bytes = [Float]()
    for index in 0..<vertices.count {
      let vertexPointer = vertices.buffer.contents().advanced(by: vertices.offset + vertices.stride * index)
      let vertex = vertexPointer.assumingMemoryBound(to: (Float, Float, Float).self).pointee
      var vertextTransform = matrix_identity_float4x4
      vertextTransform.columns.3 = SIMD4<Float>(vertex.0, vertex.1, vertex.2, 1)
      let position = (transform * vertextTransform).position
       
//       let classification = classificationOf(faceWithIndex: index)
//
//      if(classification == .wall || classification == .window) {
//        print("this is a wall")
//
//      } else {
//        print("not a wall")
//        continue
//
//      }
       
      bytes.append(position.x)
      bytes.append(position.y)
      bytes.append(position.z)
    }
    return (bytes, bytes.count / 3)
  }
}

You will see I have some commented code, I tried to use the classificationOf extension from the developer docs, but I can't quite figure out how to classify individual points and remove them.

Any help would be appreciated.