this script reverses the order of render layers in the new Render Setup Window in Maya 2016 and above

20190204_maya2017_renderLayersReorder_v002.py

# 20190204_maya2017_renderLayersReorder_v002
# Written by Patrick Woo ([email protected])

# this script reverses the order of render layers in the new Render Setup Window in Maya 2016 and above
# the scene must have at least 2 render layers to see the re-order effect

# changes:
# - the first item in the list can now be re-ordered just like the rest of the layers, by first detaching then re-attaching
# - this version allows re-ordering every render layer by first detaching them (previously there was no detaching)
# - if you have the Render Setup Window open, the layer order now reflects and refreshes without having to re-open the window

def render_layers_reorder():
    # code for querying render layers is taken from
    # https://fredrikaverpil.github.io/2017/05/07/querying-render-setup-in-maya-2017/
    # [email protected]

    import maya.app.renderSetup.model.renderSetup as renderSetup

    render_setup = renderSetup.instance()
    render_layers = render_setup.getRenderLayers()

    print ('initial order of render layers')
    print ('{} render layers, {}'.format(len(render_layers), [x.name() for x in render_layers]))

    reverse_list = render_layers
    reverse_list.reverse()

    # detach all child layers
    [render_setup.detachChild(x) for x in render_layers]

    # re-attach the re-ordered child layers (the first layer has the position of 1, not 0)
    [render_setup.attachChild(idx, x) for idx, x in enumerate(reverse_list, 1)]

    print ('final order of the render layers')
    print ('{} render layers, {}'.format(len(render_layers), [x.name() for x in render_setup.getRenderLayers()]))

render_layers_reorder()