- [Instructor] Now I'm going to talk about the Spline Function.
You can either download the Exercise File
or select F1 on the keyboard,
if you have the help documentation,
download the file and open it up.
Let's get to it.
So, here we have some points
and the way the Spline window works is,
you'll notice before we actually pick anything,
is you have a little radio button right here.
Add Point After, Add Point Before,
and Replace Point, it's very important you pay attention
to these as you're creating your spline.
By default, it's always add the next point
after the first one you selected.
There's Point 1, Point 2, Point 3,
and you'll notice the spline goes directly
through those points.
I'm going to open this up
and you'll see, here's Point 1, Point 2, Point 3,
number of points, and go on my merry way
by selecting the rest of these points.
Pretty straight-forward.
I'm going to cancel, go back into Spline,
and I'm going to select these in the opposite direction
and I'm going to open this up,
and what I want you to notice here is,
in this case, this is Point 1,
but the name of the actual element
that it's picking is Point 7,
so this is the order of points.
Order of points, the name of the actual element,
is something completely different
than the order that they're selected in.
And this, these options are in regards
to the order of what you have selected,
so if I accidentally selected this point
and I realized, hey, wait a minute,
I need to add this point in,
if I say Add Point After,
what'll happen is this is just going to swing around
and come through
Point 5 to Point 6.
Well, that's not what I want.
I'm going to make sure I have Point 6 selected,
I'm going to come say Remove Point.
What I want to do is, I want to say Add Point Before,
so by toggling this little radio button.
Now when I select this,
it's going to add the next point before five,
so this one becomes five, this one becomes six,
and if I want to come in and select the next point,
again, I have to be careful.
I have to come in to the last point, Add Point After,
select my point to make sure
that I get my spline the shape that I want,
basically selecting those points in order.
So, these are meant for, if you made a mistake
or you need to replace a point,
oftentimes you get a new curve
or a new set of points that your curve needs to run through
and you need to, basically,
switch out on point for another.
Now, other things that I can do
with the Spline tool is,
you'll notice Point 7 is currently highlighted.
I can impose a vector of tangency at this end.
So, by picking this line,
it is now tangent to that line.
I'm going to reverse the arrow
'cause I want it to come in this direction.
It's still remaining tangent to this element.
If I go to the Show Parameters button,
you'll get a few additional things
that you can do with that constraint at that end.
Currently, by default, it's set to Tangency.
I can change this to Curvature.
Basically, what it means is across that point,
you're absorbing the radius of the next curve
or that tangency vector.
In this case, it's just a line,
so it's just making it a little bit flatter
across that point.
If this were going to another curve,
then you'd get that curvature,
which, in certain cases, you really want.
You want something very smooth.
If you look at the exterior of a car
or interior body panels,
anything with highly-stylized surfaces,
aircraft, where you want a certain amount
of aero smoothness,
you're going to want to use this Curvature Continuity.
And the other thing that you can do
with these Continuities is increase the tension.
So, it's almost like adding
or reducing weight at that point,
so you're changing the shape of that curve.
In some cases, you need to make it smoother, flatter,
absorb more of the curvature,
or maybe it still wants to be Curvature,
but you can't have as sharp a transition across that point,
so you can flatten it out a little bit.
So, if I want to do that same thing across Point 1,
I would come to my window,
select this first point.
Remember, this is the order of points selected,
not the name of.
Specify the curve, it is going in the direction that I want.
You'll notice again, by default, that it's Tangency.
I can switch this to Curvature
and again, adjust
for those points.
I can do this with any of these points.
I can come to Point 2.
If I have another curve in another direction,
I can pick that as well.
So, you can see,
tangent through, tangent through,
well, this is actually curvature,
tangent through this point.
Now, I can specify Curvature,
flattens out a little bit.
So, Spline Function is incredibly powerful.
Now, if you're coming off of other systems
that use nothing but, let's say, NURBS type splines,
you don't have the control here
to manipulate the amount of math the spline has.
The orders or the degree or the segments,
you're going to get what you get.
This is a Parametric Spline Function in CATIA.
There are other Spline Functions as well,
that allow you to do that,
but not inside of Generative Shape Design.
So, if you're look at this from more
of a stylist perspective
and you want to simplify that curve,
you just have to be really careful
with the points you select here
and make sure the points are going to give you a nice,
perfectly smooth curve.
So, if you're looking for a different type of curve,
NURBS curve that, again,
that's going to give you control over the type of math
that's in that curve.
Just go somewhere else and use a different spline.
Now, for this, for Generative Shape,
this is the spline that we're going to use.
Again, very powerful.
You can impose tangencies, you can impose curvatures.
If you want to, you may need a close loop,
so you can turn on a Close Spline as well.
So, very powerful, be careful with the way
that you put points into the spline.
You have the ability to reorder how they go in
and of course, you have the ability to remove points.
And again, something I should quickly talk about as well,
is maybe if I accidentally impose a tangency on a point
that I didn't want, I can always come down here
and you'll notice I have a Remove Tangent.
I also have Remove Curvature.
So, again, upon the point that you have selected,
this is going to show you the inputs
for that one specific point.