- [Instructor] Sometimes you just need to make
a surface bigger.
And we have a couple tools that I wanted to discuss.
One of 'em is called extend sheet.
So here I have a surface, you can see it's just a body.
Maybe you translated it in.
You lost the parameters of the surface,
and you need to extend it out.
So there's a tool called extend sheet.
The way this works is you basically are
picking the edges that you want to extend out.
And I'll start off with this edge.
Now in this case, you can see what's going on,
as it extends out, it's going out beyond
where these two edges come together as a vertex,
and it just goes on beyond.
You can see it wants to extend that surface out.
Now, as I look at this surface.
I'm gonna go and pick this edge as well.
I can see that now, because I have a chain of edges,
it's not going to terminate at that theoretical.
It does a really nice job.
There's different ways that I can extend this out.
Right now, I have it set to natural tangent.
And if I look at the way that it's extending out,
I'm gonna go change this from tangent
to natural curvature.
Let me bring this up over here
so this doesn't get in the way.
What's happening is when you hover over the top of this
it just sends out this little flag
indicating what it's doing.
So you can see natural curvature has this shape.
Natural tangent is just a little flatter
'cause now it's coming off with the tangent
rather than the curvature.
The curvature has a little bit more of the actual
surface shape curvature being imposed.
And then you have what's called mirrored.
This is probably gonna have the most radical
shape change because it's basically
mirroring as you can see here.
It's mirroring the curvature from the other side of the edge
across that boundary.
So this is gonna give you the most radical shape change.
Play around with 'em
to get the shape that you want on that extension.
If I come in here, you'll notice again I can pick
as many of these edges as I want.
And it'll simply do that extension.
I can also, let's do this, I'm gonna deselect,
and show you what it's doing.
I can also change the extension shape.
And this is in regards to what's happening
here at this corner.
Right now, it's set to automatic,
so it's just taking a stab at it,
saying, hey, this is what I want it to be.
If I change this to tangent,
well you can see automatic had already
selected tangent for me.
And if I change this to say orthogonal,
now you'll notice it's coming off orthogonal
to that edge, or perpendicular.
So from here, if you measure this,
it's basically 90 degrees.
And again, it's all depending upon the shape that you need.
Again, this is the tangent extension.
You also have options to extend up to something.
So if you have a surface that you want this to extend up to
you can pick that surface as a boundary.
Next is what's called a body output.
You have these options in here as far as
extend original sheet, extend as new face,
extend as new sheet.
So if I say extend as original sheet, and select okay,
what it does is it basically extends
as part of the original sheet you have no boundary.
I'll double click on that to modify it.
I'll come in here and change that say extend as new face.
Now, you'll see that I have the boundary in there,
and it is a separate extension.
Just to show you what's happening.
If I come in and do an offset, for example,
and I say tangent faces, and I pick this,
you'll see that it does the offset,
picks all the tangent faces 'cause it's all one body.
But with a division in between those.
Go to extend sheet, and now I'm gonna change this
to say new sheet.
So it's its own separate sheet body.
Now when I do my offset,
tangent faces and pick that,
you'll see it only picks the one surface
'cause it's not joining them together.
Even though it looks like they share a common boundary,
they're two separate surfaces.
Alright, so let's go ahead and undo that extension.
Get back to the base.
The next tool that I wanna talk about is called enlarge.
Now enlarge does something a little different.
Okay, it's located here under edit surface.
And what this does is when I pick the initial surface,
the first thing it does, as you can see,
is it untrims everything.
So it takes it back to its original untrimmed shape.
And oftentimes, it's best to do this
because you're using the original parameterization
of the surface, so in this case,
it takes it back in nice parametrically rectangular surface,
and then if I just simply hit okay,
you'll notice there's the new surface.
It's not gonna attach it or anything like that
with the extend.
This actually creates a wholly separate surface
that is now fully untrimmed to its original boundaries.
This is really great if you're importing data
from other CAD systems that has been trimmed
and you wanna return things back to its original size.
Now, if I double click on that enlarge sheet,
I have various options here as well
to actually extend the size of that sheet.
And parametrically, internally, mathematically,
that surface stays the same.
It's just recompiling the math of that surface
and extending it out.
So, this enlarge again is a great tool.
Oftentimes if I can, I use the enlarge first,
like if it's a singular face like this
and I wanna untrim it, I definitely use the enlarge.
If I just need to extend out a couple of edges,
I definitely have to use at that point the extend sheet.
As far as the way that it does the enlargement,
you'll notice that I have linear and natural as well.
So you can see here, I have a linear shape,
or a natural shape.
And again, that really shows when you're doing something
on a surface with a lotta curvature.
You can also do in this case a negative
in one of the directions, or all the directions.
So if you wanna untrim it and then just shrink it,
you can shrink it.
So that is the enlarge.
And again that is under the edit surface
part of the ribbon.
So extend sheet, one boundary or the entire boundary.
Or enlarge, untrim, and then make bigger or smaller.