Nuke; Production Workflows; Environment Maps - PartA Video Lecture | Create Visual Effects with Nuke - Professional Skills

in this tutorial we will be looking at
extracting environment maps from nuke 3d
scene in particular we'll talk about
spherical maps also called light longs
and cubic maps also called six-packs
let's have a look at our 3d scene first
this is a full 360 pennant I'll set and
all the setup lives inside the group too
so let's have a quick peek at that and
you'll see that the whole thing pretty
much consists of cards so now let's say
you have this environment just home into
it and pin around so you have this whole
thing but now you need to go ahead and
retouch the shadow you need to fill in
the gaps at the bottom and the top that
we missed when we shot it and maybe you
want to use the whole setup to actually
light your CG so you need to extract a
spherical map to use as a lighting probe
the easiest way to do this is to attach
a scanline renderer node and flick it
into spherical mode like cell this will
output a spherical map however be aware
that in this mode the scanline renderer
node needs to actually load all those
tiles at the same time to be able to
process a single scanline so this can be
very memory intensive and
computationally heavy however if you do
have a machine that can cope with that
sort of stuff
make sure you render a two to one image
aspect because the spherical map covers
a 360 range 360 degrees horizontally and
180 degrees vertically so you want to
make sure you're running a two-to-one
image aspect render and the way I
usually do it is by simply attaching a
reformat node to the background pipe you
can use any node that produces or has a
format and if you have a format setup
you just simply go and choose it I don't
at the moment so what I usually do
because I don't like setting up formats
if I don't have to I just
flick the whole thing into box mode hit
the forced to shape button and then I
can punch in an arbitrary resolution so
let's go for eight hundred by four
hundred pieces as our render resolution
and in order to not bore you with the
rendering process I have done this
already here so let's have a look at the
output this is what it looks like we get
three-sixty coverage horizontally and
180 degrees vertically and now we can go
ahead and retouch those black areas or
simply put it on a sphere to use in our
scene as a single texture map rather
than millions of tiles so if you do want
to put this back onto a 3d sphere either
a nuke or my or any other 3d software
you should be able to simply use the
spheres negatives UV space which means
you just plug it straight into the
sphere however usually a spheres UV
space assumes that you're looking at the
outside of the ball like so but we're
really inside of the bubble looking out
and because of that we need to mirror
the texture map first
so I'd pin the mirror node switch on the
horizontal checkbox and now we've got
what we had before except we have a
single piece of geometry and a single
texture to deal with so if we just
quickly compare what we have now to the
original pennant I'll set up which is
here you can see that everything lives
in the same spot and if we go inside
oops let me clear out their bins so we
don't see the other geometry anymore so
now we can flick between tileset and
sphere you can see the resolution hit
which we introduced through rendering to
a discreet resolution obviously you have
to commit to some sort of resolution up
here that's one of the downsides of
using a lat/long the other downside of
this is actually that the scanline
renderer node produces so-called
vortexing at the poles so you see a
black artifact at the top and you can
also see a similar kind of artifact at
the bottom here unfortunately that's a
limitation of the scanline renderer node
at the moment usually you can adjust the
tessellation max to kind of get around
that but that gets really really slow
very quickly and you'll never get rid of
it entirely so let's have a look at an
alternative way of creating this