Blender render

hander.py

import bpy
import json
import os


class DataCombiner(object):

    def __init__(self, path_to_renders, path_to_groundtruth):
        self.path_to_groundtruth = path_to_groundtruth
        bpy.data.scenes['Scene'].render.filepath = path_to_renders
        if os.path.exists(path_to_groundtruth):
            os.remove(path_to_groundtruth)

    def _form_output(self, frame_num, vector, quat):
        output = ' '.join([str(frame_num)] + list(map(str, list(vector) + list(quat))))
        return output

    def _my_handler(self, scene):
        with open(self.path_to_groundtruth, 'a') as w:
            print(self._form_output(scene.frame_current, scene.camera.matrix_world.to_translation(), scene.camera.matrix_world.to_quaternion()), file=w)

    def apply_handler(self):
        handlers = bpy.app.handlers.render_pre
        handlers.clear()
        handlers.append(self._my_handler)


# // "bpy.context.scene.cycles.samples":1000,
def main():
    with open('config.json') as config_file:
        config = json.load(config_file)
    bpy.ops.wm.open_mainfile(filepath=config['model'])
    D = DataCombiner(config['path_to_renders'], config['path_to_groundtruth'])
    D.apply_handler()
    for param in config['parameters']:
        exec("%s = config['parameters'][param]"%param)
    bpy.context.scene.use_nodes = True
    tree = bpy.context.scene.node_tree
    links = tree.links

    # clear default nodes
    for n in tree.nodes:
        tree.nodes.remove(n)

    # create input render layer node
    rl = tree.nodes.new('CompositorNodeRLayers')

    map = tree.nodes.new(type="CompositorNodeMapValue")
    # Size is chosen kind of arbitrarily, try out until you're satisfied with resulting depth map.
    map.size = [0.15]
    map.use_min = True
    map.min = [0]
    map.use_max = True
    map.max = [255]
    links.new(rl.outputs[2], map.inputs[0])

    invert = tree.nodes.new(type="CompositorNodeInvert")
    links.new(map.outputs[0], invert.inputs[1])
    depthViewer = tree.nodes.new(type="CompositorNodeViewer")
    links.new(invert.outputs[0], depthViewer.inputs[0])
    # Use alpha from input.
    links.new(rl.outputs[1], depthViewer.inputs[1])
    fileOutput = tree.nodes.new(type="CompositorNodeOutputFile")
    fileOutput.base_path = "depth_maps/"
    links.new(invert.outputs[0], fileOutput.inputs[0])
    bpy.ops.render.render(animation=True)

if __name__ == '__main__':
    main()

config.json

{
	"model":"/Users/Documents/test1.blend",
	"path_to_renders":"imgs/img",
	"path_to_groundtruth":"groundtruth.txt",
	"parameters": {
		"bpy.context.scene.render.engine":"CYCLES",
		"bpy.context.scene.render.antialiasing_samples":"8",
		"bpy.context.scene.render.use_bake_antialiasing":false,
		"bpy.context.scene.cycles.samples":1000,
		"bpy.context.scene.render.resolution_x":256,
		"bpy.context.scene.render.resolution_y":256,
		"bpy.context.scene.render.resolution_percentage":100
	}
}

run:
blender handler.py