- [Instructor] A very important concept you have
to understand when creating any kind
of aesthetically pleasing surface is continuity.
I'm going to use these curves to demonstrate continuity.
It's the same for curves as it is for surfaces.
Now when I look at this end, I can see that I have a corner
between this curve and this curve.
It is obvious because of these needles that I'm showing.
These needles represent the amount of curvature
at that point on that curve, or these curves.
Because the endpoints touch,
but the needles are not parallel, I have a G0 condition.
G0 means position.
If I go to the other end here and take a look at this,
I see these needles are parallel.
This is G1, which means tangent,
but because they're not the same length,
they don't share the same curvature.
Tangent means just like a standard edge blend
or just a corner break.
You can see where it's at on a surface.
It's typically not the prettiest thing.
Sometimes it scatters light depending on the shape.
So when we're getting into high quality stylized surfaces,
we need to go into G2 or even G3 depending on
where you're working.
To demonstrate G2 I'm going to double click
on this bridge curve, and I'm going to come over here,
change this from Tangent,
as you can see it's G1, and go to G2.
Once I do that, you can see that across that point,
here, they now share the same length.
That means that they have the same curvature
across that point.
I'm going to double click on that bridge curve again,
so that is G2.
If I go to G3, which is Flow,
now they share the same rate of change,
or have the same acceleration coming into curvature.
So as you can see here,
that basically stretches back a little bit further.
So this is this smoothest type
of transition mathematically that we have.
For interior trim, things of that nature,
on larger panels, G2 is more than acceptable.
When you get into things like body panels,
big long swoopy shapes, or flatter body panels,
maybe you're doing something that's highly stylized,
then G3 is something that you're going to have to use
across big large panel boundaries.
But when you get into smaller corners and tinier blends,
that type of thing, if it's a highly reflective surface,
you're going to want G2.
Again, that's for smaller areas, tighter things.
On an interior piece,
you may have just mathematically something
that is G1, mathematically,
now remember this is a mathematical interpretation
of what's going on between those curves,
so this is true mathematics, but visually speaking,
you may have two shapes that have curvature
that have shape to them
that are maybe a conic and and a spline,
maybe they don't have a true mathematical relationship
of curvature, but because both of them
are smooth flowing shapes, where they come together looks
like it's curvature continuous.
So there's ways to kind of fudge these things visually,
even though mathematically they may not be perfect.
So as you're going through and designing things,
you may not have a true mathematical representation
of curvature, but visually speaking,
you may have something that looks like it's curvature
or even have a perfectly smooth flow
between those two surfaces.
So it's one of those things that as you work through
and create surfaces, creating class A high quality surfaces,
you're going to start getting an eye for does it look good,
is it mathematically accurate.
Sometimes you have to find the balance between the two.