- [Narrator] In this lesson,
we will start working on our Aurora borealis element.
So, ready your reference sheets and lets get to it.
Just as with all node-based workflows,
there are limitless ways we can construct this element
and the one I am going to present you with
is just one that I've come up through studying
various tutorials, namely those by CG Geek
and one by Dylan Neill,
both of which you'll find in the links below.
I experimented with them, added some of my own changes
and possibly even improvements,
and came up with this workflow,
which is versatile enough for my needs.
So, I have a separate project here
and lets start with a Cube this time.
Scale it on X and make it a little slimmer on Y
then apply the scale to not have the shape distorted later.
Add subd modifer of 2 and in edit mode,
add one edge loop down here,
so that when we smooth the geometry,
the bottom will be more or less straight here.
You can have a look at some reference images
of Northern Lights,
and you can see, while the top is pretty much random,
the bottom stays more or less flat.
Okay good, that's the base for our Aurora,
you can also add a few loop cuts here,
to support the edges,
and also, we'll change the shape a bit,
making it swirly.
You can also right click and shade smooth.
Let's focus on the shader editor
and create a new material for it,
adding an emission note,
while getting rid of the BSD F1.
Plug the emission into volume into the surface
and check if your streak is thick enough.
Meaning, if the emission is very dim,
you should probably increase the thickness of your cube,
until you see at least a bit of white.
Some like this.
Now in the Emission, we have two sockets,
one is Color, the other one Strength.
Well, first one we'll be focusing on is the strength,
and we'll add color later.
Let's start with making a base for our northern lights,
by adding a gradient texture node.
Make it Linear and by itself, it give you this gradient,
from left to right.
However, I want it to fade from the bottom to the top.
So, with Ctrl T as always, lets add mapping network,
and make sure you have coordinates set to Generate.
All you have to do then is to rotate your gradient
on Y axis 90 degress.
However, I do not want a perfect top to bottom gradient,
I want it to vary a bit.
You can see, aurora has a bit of more intense bottom here
and less intense top.
So, as usual, lets add a Color Ramp here and first off,
I actually want white on the bottom and black on the top.
To switch it, just flip these two colors points.
That did it.
Next, lets add a few new points.
First of all, I want a bit softer edge down here,
so add a new stop and push it to the left like this,
to create a black edge on this side,
followed by white stop right next to it,
which gives us softer transition.
Next, add one more point here, make it greyish,
and push it somewhere in between the right hand side points,
until you crate a shape, somewhat like this.
Good, that our base shape
and you can already add a greenish cyan color it,
if you want.
Into this we will mix in a few more noises,
just like we've been doing all the time
in our node-based workflows of this course.
So first, I want to mix in these streaks you see
on the reference images.
We can of course create them with a Noise texture, again,
Ctrl T on it to add in the Mapping nodes,
to see it better, we've in fact plug it here by itself,
and play with the values.
Make the Noise Texture 4D,
that will allow us to animate this W value later,
to make the aurora animate it
and add a Color ramp behind it.
Right of the bat,
make the shapes a bit more pronounced
by sliding this black point of the color ramp
to about 0.5 value.
Then, make the Noise scale smaller, like one,
detail of 1, so that its not too detailed,
rather smother, which you can also achieve
by lowering the roughness.
Finally add a bit of distortion, like 0.5.
Next step is to play with the scale value
and the mapping node.
This will depend on the shape of your object,
but this is what we are after,
this high streaks.
Usually you achieve them by raising the X value a lot,
raising the Y value and then leaving the Z to one.
Then, hold down Ctrl and Shift and right mouse button drag
from this color ramp to this new one
and it will automatically combine both in this Mix node,
switch it to Screen mode at 0.5,
or six, or seven, or 692.
But of course, make sure its plugged into the strength.
Cool, then these as our gradient and these as streaks
and I hope I don't have to mention
you should definitely experiment with the values here,
I think I've mentioned this in every chapter,
but yeah you should.
Now this is going in the right direction
but I definitely want to add more randomness to the mix,
you can see the Auroras are a lot more unpredictable
on these images,
In the desert chapter, you learned,
that to make these default textures a bit more random.
You can simply mix in another noise texture here,
before the main texture node,
which will distort the whole coordinates system.
So lets do it, add a basic 3D noise texture
with about scale of one, detail of one
and distortion of one.
And I mix it in here with a RGB Mix node
and plug in its own set of coordinates,
but set it to object,
so that we used blender's default coordinate system rather
than that of the bounding box of your object,
which we would do by using the Generated one.
Now if you play with this factor value in the Mix node,
you can see how the the New noise is affecting
the shape of the streaks.
You don't have to go too high with this,
a value of around 0.6 will do, and we can in fact,
even lower the scale of the noise to 0.5 or 0.6.
Now as you can see our shape is a bit too regular,
I want it to be randomly brighter and dimmer
on various parts.
That why we'll add this new noise
on top of our network.
So, let me add a new noise setup here with color ramp
and all, making the texture 4D again,
scale of 1, detail of 1, roughness 0.2
and distortion around 0.5.
Let me plug in just this new network here into the strength,
to see it better.
In the co-ordinates of this new noise,
play with the scales
until you achieve something like these shapes.
This will become more apparent
when we drive the black point more to the middle,
as well as the white point to about 0.7.
That way that the contrast is increased.
Cool, and if you reconnect everything and plug
this in with overlay set to slightly higher intensity,
it will then randomize the intensity
of the whole noise a bit.
However, now it is getting quite dim.
Fortunately, we can improve that by adding a Math node here,
and switching it to multiply.
To make everything more emissive,
set this value over one.
Oh, and don't forge to make a new frame out of this
and name it, for example, Randomize.
Okay, now all we need is a bit richer color palette
and also, getting rid of these sharp top and side edges .
That will be the topic of the next lesson.
(soft music)