- Subdivision surface modeling
is a technique to create smooth flowing surfaces,
such as a character, creature,
or even the soft cushions of this office chair.
In this scene, the seat cushion
is an active OpenSubdiv object.
I can change its level of detail at will
while preserving its overall shape.
The other objects have all been baked,
or converted to editable poly.
To see this more clearly,
let's enable edged faces with F4.
Although the seat cushion at the bottom
looks round and smooth,
it doesn't actually appear to have as many polygon wires.
Well that's just due to the display mode that we're in.
Let's investigate. Select that seat cushion,
go over to the Modify panel.
And we see that the stack consists
of an editable poly base object.
Above that there's a Symmetry modifier.
That will reflect the polygon surface to the other side,
so that we only have to model half of the object.
At the top of the stack,
is the OpenSubdiv modifier.
Its function is to subdivide the polygons
on the base object.
Not only that, but it averages the angles
among the new subdivided polygons
to smooth out any jagged corners.
If we disable that top modifier
by clicking on the visibility or eye-icon,
we see the original polygon mesh.
This is what is known as a control cage.
It's merely a means to an end.
We're never going to actually render
or export this low-level of detail mesh.
We use that control cage as a tool
to sculpt with subdivision surfaces.
Okay. I'll re-enable OpenSubdiv.
If we want to see the actual level of detail,
or the individual polygons after they've been subdivided,
we can disable this option here.
Isoline Display, turn that off.
And now we're seeing all of the individual
subdivided polygons on the object.
We can zoom in on the selection with the Z key.
The most important parameter
of a subdivision algorithm,
is its number of Iterations,
or number of repetitions.
This is the number of times a mesh will be subdivided.
If we change the number of Iterations,
we increase or decrease the level of detail.
Bring that down by clicking on the spinner.
So with an Iterations of one we have a blockier object.
With an Iterations of zero,
we have the original control cage,
or the original polygon mesh.
As we increase the Iterations value
we get more detail on the surface.
An Iteration value of two or three is usually optimal.
You see if I take it up to a value of five,
I've got an extremely dense mesh here, and that's overkill.
We don't need that.
I'm going to bring this back down to what I had,
which was a value of two.
Subdivision surfaces have been implemented
in several ways in 3ds Max.
It's been around for a while.
And so the design of the software implementation
has evolved over time.
The OpenSubDiv modifier is generally the optimal workflow
because it has the best performance,
and the best compatibility with other applications.
It's based upon an open standard,
the Open Subdivision Surface standard.
We can also subdivide meshes
with other modifiers.
In the Modifier List,
we have several other ones.
We've got something called MeshSmooth.
There's also one called TurboSmooth,
which as the name implies, is a little bit faster,
and there's even one called HSDS,
which stands for Hierarchical SubDivision Surfaces.
Any of these will perform more or less the same function,
but OpenSubDiv is faster and better.
So I'm not recommending that you use those other modifiers.
And in fact, if you see a tutorial
that references those other modifiers,
I do recommend that you use OpenSubDiv instead.
Subdivs are also built directly
into the editable poly object
and the Edit Poly modifier.
That can come in handy sometimes,
but in most cases, the workflow I'll be demonstrating
with the OpenSubDiv modifier
is the most effective and flexible.
That's a basic introduction to the concepts
of subdivision surfaces, and how they're implemented in Max.