all right let's check out the MILA material which is
new to Maya 2015. It's a new Mental Ray shader
that controls layering and allows us to do some interesting things
Right now all my spheres are Lamberts
I'm assigned my new material to the sphere
in the center and render that out, and by default, the MILA material
looks just like a Lambert. If I look in the parameters
my MILA, I've only got two options: color and roughness.
And rendering those out gives me a Lambert, nothing too interesting
I'm going to skip that right now and go straight
into layering by clicking my 'Plus Layer'
and the first thing that I need to do is
choose what type of layer I want to add.
A weighted layer is a layer that's controlled by a simple opacity mask.
A fresnel layer is a layer that has fall-off similar to what we have
reflectivity for the MIA material
MIA material and the custom layer
can be somewhere in between. So I'm going to stick with the weighted layer
right now. Now I have to choose the elemental component
and the elemental component is what we think of
when we think of the material. So Lambert or Blinn,
the elemental components determines that for us.
The layered material divides everything up
in to separate components. My glossy reflection controls the reflectivity
of my surface. The diffuse reflection is
my regular diffuse. So I'll add one of those
and I can change the color to whatever, and when I render,
no big surprises, I get a purple
colored Lambert. Now, because these are layers,
and this is a weighted layer, I can adjust the weights to adjust the way the
material looks.
Weighting becomes interesting when we start plugging textures
textures into the weight channel. I will add a texture to my weight,
and use the checkerboard texture to create an alternating
pattern. And I see I have a red
and purple looking sphere. FANTASTIC
Let's add another layer by clicking the Plus Layer button,
and choose what type of layer we want to add.
I want to create a
chrome ball, so I am going to create
'Layered' instead of 'Fresnel', because I want it to be entirely chrome.
I'll choose glossy reflections from the elemental components
and because this is Maya
is Maya in Mental Ray, there are still a lot of bugs to be worked out, because this is a
brand new functionality.
A lot of cases, the order that the layers are in,
will show up incorrectly. So we have to know how to fix it manually,
and in this case, we see that we've gotten a weird mix where the glossy
has now switched so that it's on top, but it somehow absorbed the checkerboard
texture from the purple diffuse.
So I'm going to right click on the weight parameter and break
that connection, and I will turn that off for a moment,
by just turning this check box off. And now I want to plug
plug my checkerboard back into my diffuse so that I can control the opacity
so I found my checkerboard, and I will middle mouse drag it
on to the weight here and
I'm back to the original checkerboard texture. So I'll turn my glossy reflection back on
and we get kind of a preview of what's happening
down here. When I render we'll see something similar, except it's actually going to
reflect the environment around it.
And it's sitting on top of the two layers that I already have
because the weight is set at fifty percent. If I set it up to 100 percent,
and I re-render, I will get back chrome
ball I was looking for. Now we will notice it isn't perfectly chromed
because it is noisy. It has gloss on it.
With my glossy reflection layer, I can control that using the roughness.
I can set my roughness down to zero
to get a perfect mirror ball.
Just like this.
Let's say that I want that mirror ball to you appear in the checkerboard
pattern that I had before
before, I could use this same checkerboard texture to
control the opacity in the mirror ball, just by plugging that
checkerboard in the glossy reflections weight.
And now I will get a texture that alternates between
the red diffuse at the bottom, and the
chrome in between. I'm going to create another brand new
MILA material. Again, Mental Ray materials, MILA material
and I'll assign that to the center sphere.
I re-render that, and I'll be back to square one
my boring gray MILA material,
no surprises there. So let's start adding some other layers and see what are other
options are.
First, let's talk about the Fresnel layer.
I will plug one of those in, and use my glossy reflection again.
If I re-render with Fresnel enabled
enabled, I'll see I get a little bit of reflection around the edges.
This is an actual Fresnel reflection, we can change
the reflection. We see that we add that glossy reflection
with Fresnel on it, we get an IOR control.
I can turn that up, and the higher that IOR number gets,
we'll see the more reflective the sphere becomes.
If we compare it to before, the sphere looks not entirely reflective
in the center. Now we're getting a bit more reflectivity.
And again, we also have that roughness that it assigned to it
by default. I can adjust that, turn the glossiness down
and I have more of a reflective sphere sitting on top
of that. So that's
sort of interesting. Let's add another layer.
I will create a weighted layer that is
diffuse reflection, and I'll make this one
blue or whatever. Maybe not that blue...
and I want to change this
layer's position in the stack. I want to put this
under my glossy reflection. So...
there IS an arrow key right here, and all the layers have
these little arrows on it. And I can click on it and
in some cases it will switch exactly like it just did. In other cases,
it will act a little bit wonky like we saw on the first sphere.
But now when I render this I'll get a
base blue layer with some reflectivity
on top of it. So that's kind of interesting.
Let's play around with our bump channel here. So we do have a bump map channel, and I will
plug a texture into the bump map
channel, for my diffuse reflection. And I will just use a fractal
fractal to make it look noisy. Now I've got that fractal plugged in,
and I'm going to re-render with that new noise map
applied, and I'll see
it doesn't look right. This is because the fractal
is plugging directly into
the layer. What we actually need is to go into the utilities in our Hypershade,
create a Bump2D node manually, plug my fractal
into that Bump2D node, and then come back in and plug that bump node
back into the bump channel on my diffuse reflection. Now the bump has
been plugged in there
and when I re-render, now
I get a bump that looks relatively correct.
We're also seeing something interesting here
I'm going to turn my glossy reflection off so, that we can compare,
but I have a glossy reflection that sitting on top up this noisy material,
and we'll see that the glossiness is not perturbed by
the bump map of the layer below it. So I'm getting a kind of shellac,
where I have a very smooth reflective layer
thats applied over the bump layer.
This is something we might want to use if we actually have a shellac material
for doing car paint. If we want the
reflection to agree with the bump map,
we just need to add the bump map into the reflection's bump channel
channel as well. I'll plug that same bump node into the bump channel there
and when I render, now I'm going to get
a surface that has that reflectivity. And the reflectivity
is going to have a lot of noise as well.
It does finish rendering, and we see that it does indeed look like a very noisy set
of reflections, and
as with most cases when using a bump map in Maya,
I almost always reduce that bump depth (in the Bump2D node), otherwise we get
something that is disproportionate
to the effect that we're looking for. So every time we try and add a new layer,
it's giving us problems
so let's take care of this manually. I'll go into
the layer node itself, and I'll try to do the
work in here. At the top of
the layer node, we'll see 'Add New Item'. This is basically the same thing that we do
when we click the Plus Layer button. The only catch
is, I can keep clicking this, and these (new layers) all show up at the bottom.
Just like in Photoshop, the layers in the bottom are
covered up by the layers on the top.
I have the problem that I can't see any of the new layers that I add!
So I'm going to have to plug these back in
manually. Here's my blue base color, I'll just
middle mouse drag that on to the shader
for the layered shader. And I'll find my glossy reflection with the red
and what I like to do to increase flexibility
is to skip slots, so if I have to at something
later, I don't have to worry about repopulating
the entire list. Now I have the
glossy plugged in, and I'll go to the top here
and get rid of the ones that have stuff plugged into them, so I have
basically a blank material,
except for the two channels I've added. We may have problems with the MILA material
shader not updating properly.
We're also going to have problems with the blend mode.
So I plugged my glossy reflection in, but the last time we saw it,
it was obeying the
Fresnel rules. Now it seems like it's a weighted layer.
We have to change that manually. By default,
all layers are going to be weighted layers. We can change it very simply in this layer node
by clicking the 'Use Directional Weight'.
That will turn on Fresnel. Now when I render,
I'll get a red Fresnel reflection around the edges of the
surface. And if I want, I can change
the IOR. I can increase it
to get more reflectivity in the center of the object.
Now I can turn my attention to the fact that I have no bump maps.
I can grab my bump shader and try middle mouse dragging on
on to the bump node, but Maya will give me an error,
we can't do that. What we actually have to do is take note of the
numbers of the shaders that we're using. We middle mouse drag it onto the
layer node itself. And then just plug that layers' bump
into whatever layer I want it to be on. So layer 9 is my bottom diffuse
layer, and layer 7 is the reflectivity layer.
and now when I render, I get that noisy sphere that I had
before. So now I can
add in a new glossy reflection on top of
my surface. So I will skip a layer,
and plug this new glossy reflection
into this shader here. And by default,
it will be set to weight 1.0 so that when I render
it will give me a perfectly 100 percent chrome sphere
sphere. Not necessarily what I want.
What I want is a feeling I have a shellac over the rest of
this bumpy object. In order to do that,
I need to adjust my material
so that it is using a directional weight.
That will set it to Fresnel. Now when I render it, I'll get some
edging around it. I can also change the directional weight mode.
I can set it to custom instead of Fresnel.
With custom, we ignore the IOR. Instead we use Normal
and Grazing reflectivity. Almost every material
is going to have a 1.0 grazing reflectivity
the normal reflectivity controls how much reflection we're seeing
in the center of the object.
I'll set it to 0.5 to make it very very reflective
and now I'll get a reflective layer sitting on top of
the other layers I had before. And I can see that it looks like this layer
is indeed sitting on top. It is enclosing that
noisy sphere that I had before.
I could play around with these different values to get different
reflection types but the overall goal is to make it look like I've got that shellac over
the surface, and I've got that. I'm going to assign this material to my other sphere,
and we'll take a look refraction and transparency.
Now I'm going to control transparency here
I will start by adding a new layer and I'll set it to be
a weighted layer. I want to use
transmission to create refraction so
either a specular, a glossy, or a diffuse transmission.
I will use a glossy transmission.
This is the standard refractivity we think about when we think of
transparency. When I render, by default
I'll get a transparent
sphere. What's important to note is
this transmission layer sits on top of the
base diffuse layer. We don't see the base diffuse
layer, though. The transmission layer overrides it.
If I adjust the weight so it is only
half opaque, then I'll see the diffuse layer below it show through.
But, essentially, we replace the layers underneath
with the layers above. I'll turn that
weight back up. Because this is a glossy
refraction, it is going to have
gloss on it. No big surprise here. I can turn that roughness down, and I get a more
transparent,
more crystal-clear sphere. I can set the IOR up to
whenever material I'm trying to create.
I'll end up with that transparent glass
sphere. Now we may be looking around for "Hey! Where's my Thin Wall attribute,
I want to make some windows!" That's not actually in the transmission
it's in our material properties. I can set thin walled
walled, and when I render that now I get a very transparent sphere.
I probably won't be able to see it except for
some glossiness. So I'll turn that off because I do want
a transparent sphere. And re-render.
I'm going to add another layer
this is going to be a Fresnel layer, I'm going to create a
reflection with this. Just another glossy reflection layer that sits on
top. And I'll leave it at the
default values for Fresnel of 1.2.
We'll see now I have specularity along the edges and
some reflections. So that works pretty well.
But now I want to do some more
interesting things. Similar to the way that I have this checkerboard over here
where I have some diffuse and some reflection,
I'm going to you divvy up my materials, so I have some areas that
are transparent and some areas
that are not. I will create another layer and do a weighted layer, and
use a diffuse reflection. That will sit on top,
I'll set this to a yellow color
and if i render it's going to render faster because it's not
calculating the other expensive layers below it.
But it also gives me a not-very-interesting material.
I need to adjust that weight to give me something interesting.
I'll go back to that checkerboard again.
If I render, I get the checkerboard alternating texture.
I can see through parts of the material, and I'm
unable to see through other parts of the material. Not surprising.
I'll adjust the 'Repeat' values on the
Place 2D Texture node, so that I can control where the yellow
versus the transparent shows up.
Now it's something that's a little bit more interesting where
I have half a sphere that is opaque and half that isn't
opaque. I can try playing around these to get
other values that show up. And what we're looking for
is, can we see the material
as it passes behind the transparent object.
A quick way to check this is to
turn that thin wall back on.
I can see that we can see through it. And when it's refracting
we are seeing what it would look like, even if we aren't seeing it.
It's still in there.
That's it! Hope you found this helpful.