- Something that most people are unaware of,
is the actual beginnings
of where Class A surfacing came from.
The terminology, the tools, the verbiage.
They all have a nautical base.
Hundreds, if not thousands, of years ago
ships and boats were built using long slats of wood,
called splines.
Those splines were wrapped around control points.
There are also other aspects of where splines
were joined together at end-points called knots.
And so on, and so forth.
So, do you really want to get a good, deep understanding
of where these terminologies come from?
Go research ship building.
It's a very interesting topic and it'll give you
a really good, strong foundation
of where all of this comes from.
Now, to relate that into a CAD system,
what you see here is a surface.
That surface has control points.
These control points, control the actual shape
of that surface.
This surface also happens to have an internal knot point.
This solid blue line that runs through that.
To the eye, you won't see that.
This is something that is visualized using an analysis tool,
just to show you here in this example.
That knot point is technically two surface patches
that come together and internally they determine
that it is one giant surface across that knot point.
Again, that would be representative
of two planks coming together end to end or side to side.
These control vertices, or hulls, or control points,
depending upon what system you're using,
as they're called or referenced,
are again controlling the shape of that surface.
For a surface that requires a lot of shape,
you're going to require more of these control vertices,
as well as these internal patches.
The more shape that something has,
the more control it requires, the higher the math,
so, you're going to need a lot more of these control points.
Another example, let me hide this, and show this.
You'll see that I have this surface attached
to this surface.
These are holding two independent surfaces
that have been joined together across a boundary.
This is a splitting or a facing tool that trimmed back
that surface and joined those two surfaces together.
So, this patch is a separate entity than this patch.
They just happened to be joined as a singular surface
in this case.
This is an external boundary.
You'll hear these terms used interchangeably
through the course.
Patches, edges, boundaries, control points,
control vertices, hulls.
So, those are the most basic terms that you need
to understand when creating a nerves element
for a Class A surface.