vtkMRMLCameraNode's coordinate system

Operating system: window 11
Slicer version: 4.13.0

Hi, everyone

I want to calculate the z-buffer of an object based on the camera position.
As far as I know, the z buffer is calculated based on the camera coordinate system.

cameraNode = slicer.modules.cameras.logic().GetViewActiveCameraNode()

pos_camera = [0,0,0]

cameraNode.GetPosition(pos_camera)

Given the above situation, I have two questions.

Q1. What’s the camera’s position coordinate system ?

  • Is the coordinate system of ‘pos_camera’ a Camera(View) coordinate system or a RAS (World Coordinate system) coordinate system?

Q2. Does the camera default to perspective projection?

  • I made a depth map for the parallel projection method, but if the camera settings are different, I would like to implement it again, so I ask a question.

Camera position will be in RAS. The default camera is perspective, but it can be set to parallel if that works better for you.