tl;dr: <\/strong>Leveraging the power of the EXR metadata to create an animated Camera Node in Nuke.<\/p>\n<\/div><\/div>\n

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When it comes to designing a comp template<\/strong> intended to be used along an entire show as a base-comp (a comp from where to start working on different shots later on), being able to make it the most streamlined possible is of paramount importance<\/strong>. Here is where metadata comes into place.<\/div>\n
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Like you may already know, an EXR file can store metadata values that can be accessed and used in Nuke to dynamically drive<\/strong> the parameters of virtually any node. Hence, streamlining a so called base-comp implies automatizating certain tasks and ultimately saving time (and money), avoiding human errors.<\/div>\n
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This being said, here I share with you an example of such a thing: a Python script which is able to create a Camera Node from the Arnold Render specific metadata stored in a EXR file<\/strong>, thus making it unnecesary to export alembic or fbx caches and then saving us one step in the pipeline.<\/div>\n
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important<\/strong>: for making this work, import the script and call the\u00a0create_cam()<\/span> function.<\/p>\n<\/div>\n
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snippet<\/strong><\/h6>\n<\/div>\n
# local application\/library specific imports\r\nimport nukescripts\r\nimport nuke\r\n\r\n\r\ndef bake_arnold_exr_cam(name, eye):\r\n\r\n try:\r\n node = nuke.selectedNode()\r\n except ValueError:\r\n nuke.message("select a node")\r\n return\r\n\r\n if node.Class() != "Read":\r\n nuke.message("you should select an EXR file containing metadata")\r\n return\r\n else:\r\n cam = nuke.createNode('Camera2')\r\n cam['useMatrix'].setValue(False)\r\n cam['rot_order'].setValue('XYZ')\r\n # cam.setName("EXR_right_camera_" + node.name())\r\n cam.setName("EXR_" + name + "_camera_" + node.name())\r\n\r\n for k in ('focal', 'haperture', 'vaperture', 'translate', 'rotate'):\r\n cam[k].setAnimated()\r\n\r\n for frame in range(node.firstFrame(), (node.lastFrame()) + 1):\r\n haperture = node.metadata('exr\/g' + eye + '_cameraApertureMmH', frame)\r\n vaperture = node.metadata('exr\/g' + eye + '_cameraApertureMmV', frame)\r\n focal = node.metadata('exr\/g' + eye + '_focalLength', frame)\r\n\r\n transX = node.metadata('exr\/g' + eye + '_cameraTranslationX', frame)\r\n transY = node.metadata('exr\/g' + eye + '_cameraTranslationY', frame)\r\n transZ = node.metadata('exr\/g' + eye + '_cameraTranslationZ', frame)\r\n\r\n rotX = node.metadata('exr\/g' + eye + '_cameraRotationX', frame)\r\n rotY = node.metadata('exr\/g' + eye + '_cameraRotationY', frame)\r\n rotZ = node.metadata('exr\/g' + eye + '_cameraRotationZ', frame)\r\n\r\n cam['focal'].setValueAt(float(focal), frame)\r\n cam['haperture'].setValueAt(float(haperture), frame)\r\n cam['vaperture'].setValueAt(float(vaperture), frame)\r\n\r\n cam['translate'].setValueAt(float(transX), frame, 0)\r\n cam['translate'].setValueAt(float(transY), frame, 1)\r\n cam['translate'].setValueAt(float(transZ), frame, 2)\r\n cam['rotate'].setValueAt(float(rotX), frame, 0)\r\n cam['rotate'].setValueAt(float(rotY), frame, 1)\r\n cam['rotate'].setValueAt(float(rotZ), frame, 2)\r\n\r\n return nuke.message( name + " " + "camera" + " " + "created")\r\n\r\n\r\n\r\nclass ModalPanel(nukescripts.PythonPanel):\r\n def __init__(self):\r\n nukescripts.PythonPanel.__init__(self, title="BAKE YOUR CAM")\r\n self.menu = nuke.Enumeration_Knob('eye', 'eye:', ['left', 'right'])\r\n self.addKnob(self.menu)\r\n\r\n def getValue(self):\r\n return self.menu.getValue()\r\n\r\n def getName(self, n):\r\n return self.menu.value()\r\n\r\n\r\ndef create_cam():\r\n panel_instance = ModalPanel()\r\n if panel_instance.showModalDialog():\r\n\r\n value = int(panel_instance.getValue())\r\n cam_created = panel_instance.getName(value)\r\n\r\n if value == 0:\r\n bake_arnold_exr_cam("left", "_L")\r\n # ok_panel = nuke.message(cam_created + " " + 'camera' + " " + "created")\r\n elif value == 1:\r\n bake_arnold_exr_cam("right", "_R")\r\n # ok_panel = nuke.message(cam_created + " " + 'camera' + " " + "created") #ok_panel.show()\r\n else:\r\n pass\r\n print("next time")\r\n\r\n\r\n\t\t\r\nif __name__ == '__main__':\r\n create_cam()\r\n\r\n\r\n<\/pre><\/div>\n","protected":false},"excerpt":{"rendered":"
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