A processor system configured to process image data from a camera in a physical space to render a virtual object in a 3D virtual environment, the virtual object representing an object in the physical space, wherein the object comprises at least part of a person, the processor system arranged to communicate via a network to a server system comprising a processing resource, wherein the processor system comprises: - a network interface configured to exchange data via the network; - a capture interface to the camera; - a second device interface to a second device in the physical space, wherein the second device comprises at least one of: - a head mounted display worn by the person; and - a user interaction device configured to sense a movement of the person in the physical space; the camera having a camera pose in the physical space and the second device having a second pose in the physical space, the second pose being different from the camera pose; and - a processor configured to: - obtain image data of the physical space from the camera via the capture interface; - obtain second data of the second device via the second device interface, wherein the second data is data regarding the position or orientation of the second device in the physical space comprising at least one of: - a displacement distance of the second device; - a displacement direction of the second device; - a rotation angle of the second device; and - a rotation direction of the second device; - send the image data, the second data and a calibration command to the server system; - receive calibration data according to the calibration command from the server system, the calibration data being indicative of the camera pose and the second pose; - generate 3D object data of the object by processing the image data based on the calibration data, the 3D object data being provided for rendering the virtual object in the 3D virtual environment. the virtual object representing an object in the physical space, wherein the object comprises at least part of a person, the processor system arranged to communicate via a network to a server system comprising a processing resource, wherein the processor system comprises: - a network interface configured to exchange data via the network; - a capture interface to the camera; - a second device interface to a second device in the physical space, wherein the second device comprises at least one of: - a head mounted display worn by the person; and - a user interaction device configured to sense a movement of the person in the physical space; - a network interface configured to exchange data via the network; - a capture interface to the camera; - a second device interface to a second device in the physical space, wherein the second device comprises at least one of: - a head mounted display worn by the person; and - a user interaction device configured to sense a movement of the person in the physical space; - a head mounted display worn by the person; and - a user interaction device configured to sense a movement of the person in the physical space; the camera having a camera pose in the physical space and the second device having a second pose in the physical space, the second pose being different from the camera pose; and - a processor configured to: - obtain image data of the physical space from the camera via the capture interface; - obtain second data of the second device via the second device interface, wherein the second data is data regarding the position or orientation of the second device in the physical space comprising at least one of: - a displacement distance of the second device; - a displacement direction of the second device; - a rotation angle of the second device; and - a rotation direction of the second device; - send the image data, the second data and a calibration command to the server system; - receive calibration data according to the calibration command from the server system, the calibration data being indicative of the camera pose and the second pose; - generate 3D object data of the object by processing the image data based on the calibration data, the 3D object data being provided for rendering the virtual object in the 3D virtual environment. - a processor configured to: - obtain image data of the physical space from the camera via the capture interface; - obtain second data of the second device via the second device interface, wherein the second data is data regarding the position or orientation of the second device in the physical space comprising at least one of: - a displacement distance of the second device; - a displacement direction of the second device; - a rotation angle of the second device; and - a rotation direction of the second device; - a displacement distance of the second device; - a displacement direction of the second device; - a rotation angle of the second device; and - a rotation direction of the second device; - send the image data, the second data and a calibration command to the server system; - receive calibration data according to the calibration command from the server system, the calibration data being indicative of the camera pose and the second pose; - generate 3D object data of the object by processing the image data based on the calibration data, the 3D object data being provided for rendering the virtual object in the 3D virtual environment.