hello and welcome to our render
Channel's compositing quickart video for
V4 Revit in this video we'll go over how
to composite render channels in an image
editor for flexibility to improve your
workflow this allows you to adjust
specific components of a rendered image
to give you much better control over the
final quality of your
output start Revit and open the vrate
frame buffer or vfb here we see the vfb
with the render from the last tutorial
which you can check out and download at
the URL shown below however if you don't
wish to go through that tutorial to
generate your own render of that project
in the vfb click the load image icon and
navigate to the channels. VR IMG file
from the downloaded assets from this
tutorials web page linked below this
this will load the beauty render as well
as all its channels from that
project now the first thing to do is to
save out the render channels out to disk
by clicking the dis icon in the vfb for
the image type we're going to need a
32bit image file to use in compositing
as 8bit images won't do well choose open
exr and give the image a name and a
location to which to save I'm calling
mine compositing
this will save out all the channels with
compositing as the base name open an
image editor such as Photoshop to load
the many images we have into a single
working file in Photoshop click file
scripts load files into stack click
browse and select the files you want in
your stack in Photoshop we'll be using
the render channels that remake up the
beauty pass compositing texr is the full
RGB pass itself so select that first
then select these following
passes with everything selected click
okay I'll elapse time as the images load
into a single Photoshop file as
layers move the RGB Channel layer
composite. exr up to the top notice that
the sky area is completely cut out it is
still there but it's being cut by the
alpha Channel inherent in the file now
we just need to disable that
transparency so go to the layer menu and
select layer mask from
transparency that takes the alpha
transparency and turns it into a
Photoshop mask for that layer now I'll
drag that mask down to the trash icon
and click delete in the dialogue window
now the sky color is back in the L layer
you can repeat this procedure for all
the remaining layers or you can create
an action script like the one I've
created for you here click here and
select load actions and navigate to the
downloaded assets for this tutorial and
select the file Photoshop remove alpha.
ATN now all you need to do is select the
layer and then select remove Alpha in
the actions and click play repeat for
the remaining layers and you'll be all
done
now our task at hand is to properly
layer all these images together to
reform the beauty or RGB render and
since these are all additive layers the
ordering isn't that important first hide
the compositing exr layer to get that
out of the way now the layers all pretty
much need to stack on top of each other
using the linear Dodge add mode so
select all the layers and in the layer
mode mode drop-down menu select linear
Dodge ad to change them all at
once each layer's color information is
now adding on top of the previous layers
which gives us the beauty
pass compare with the top RGB layer and
you can see that our stack with the
additive mode is the same as our Beauty
render now that we have this we can
start tweaking the individual layers to
adjust adust the image for example I can
get rid of the atmosphere by turning off
that layer or turn off the direct
lighting from the Sun or even turn off
the reflections if I needed to the power
really comes from adjusting these layers
as opposed to turning them off or on for
example if the specular Reflections seem
too bright I can adjust the opacity of
just that layer to reduce the
specularity here to about half now let's
reduce the amount of bounced light
inside the room by reducing the opacity
of the global illumination layer I'll
set this to about 80% for a bit more
mood in the render I can also affect the
coloration I'll add an adjustment layer
with a hue saturation to be placed right
above the global illumination click this
button in the properties to have that
adjustment layer affect only the GI
layer right below it and not all the
layers below
it now I can easily remove the
saturation out of just the bounce light
in the scene and because this is a 32bit
image there's plenty of information in
the image to adjust without a loss in
quality now that I have this I can save
this image as a 32bit exr or a Photoshop
PSD pretty easily but to Output it for
most uses such as an online presentation
I need a more common file format such as
PNG or jpeg first I'll need to convert
this down from
32bit click the image menu and select a
mode 8 bits per Channel click merge and
you'll see the HDR toning dialogue here
is where you instruct Photoshop and how
to go down from 32bits to 8 Bits select
exposure and Gamma and then click okay
to get the same look down into 8bit
space as you just had in 32 two bits as
you can see using render channels and
image editing after a render gives you
great control over your final image and
is well worth the extra outputs thank
you for joining us for this quick start
video on compositing render channels in
V for Revit