- [Instructor] The technique used in surfacing is to build
slab surfaces or block surfaces
and trim things back to the appropriate sizes you need.
It's a good technique.
It's something that's been around for a really long time.
So a part of that technique is again to trim back to
the area that you need and we have tools for that.
What I wanna talk about right now is called Trim Sheet.
Basically, you select the target that you wanna trim.
And you can pick multiple targets,
doesn't have to be just one.
And then you come in, select the boundary
that you wanna trim to.
Now, with this, you'll see the curves aren't
necessarily on the surface, they don't have to be.
There's a option in here for projection direction,
so it'll project the curves down to the surface
and it gives you options on how to do that.
You can use already project curves or intersection curves
or other bodies to trim, whatever it is.
But in this case, I just have everything set up
on a sketch plane and I'm just gonna use those curves.
So I'm just gonna come in, change this to Single Curve,
pick my curve, and as soon as I pick it,
it's going to project it.
And you'll notice, it also does what's called extrapolate.
It extrapolates those ends out.
If I look at my settings,
you got that right there, Extend Boundary Object
To Target Edges.
Now, you may wanna turn that off.
And if you do, in that case, you'll see I get a little error
saying, hey, I can't trim this sheet because
technically, you can't create a cut-out with a curve
that doesn't extend all the way out.
But this can be helpful if you have a profile
that you just wanna use.
Rather than having the two or three or four, 10 curves
in a profile extend out to all the boundaries,
you just turn that off and leave it off.
But in this case, I'm just gonna turn it on.
Now, based off of this,
it's doing a projection
Normal to Face.
I can change this and use a Vector
Direction or in this case, 'cause it's a sketch,
I can just say Normal to Curve Plane.
And you'll notice that there's a slight difference.
All right, so we'll do that.
Also, you have the option,
I'm gonna leave this on Normal to Face
and I'm gonna turn on what's called Output Exact Geometry.
And here, I'm gonna get this little warning.
It's saying, hey, there are edges and/or curves
selected as trimming boundaries.
Since projection along face normals produces
tolerant imprinted edges, the results will not be exact.
So it's telling you, yeah, you have output turned on,
but using a Normal to Face projection creates
a tolerant curve.
Meaning it's gonna use a lot more tolerance.
Tolerant, that is the keyword there.
So you're potentially gonna put a little deviation
on that edge trim.
So if you want something that is precise,
you're gonna have to use a
actual vector, as you see, a Normal to Curve Plane.
This is a plane that the curve sits on,
so it's using that vector.
And now, I don't get that message.
Okay, so it's gonna be a precise trim.
So now, once I have that determined,
I go to what's called Select Region.
Click on Select Region.
Now, by default, it picks the region to keep
based off of where I first selected the surface.
If I had picked on the other side,
it would keep the other side.
Now, in this case, if I want to switch that,
I can turn on Discard and it'll keep this side.
So if I leave Keep turned on, for example, I'm gonna say,
okay, and notice it keeps that side.
If I double-click on that and say Discard,
it discards the side that's selected.
All right, I'm gonna double-click on that.
And I'm gonna come in here and I'm gonna add another curve
and another curve.
Project some down, I'll go the region.
Now, you'll notice that it's keeping just that region.
I'm gonna say Keep here.
It's keeping just that region.
And I can pick multiple regions for it to keep.
So if I want that, I can select OK
and it keeps all of those regions.
So it's really smart what you can do with it.
So you wanna make sure that you're keeping the region
or discarding the region that you want to keep
and/or discard, or multiple regions.
So if I made a mistake and I realize, oh, wait a minute,
I don't want to keep this region or that region,
I can just come over here and hit the Shift key
and deselect those additional regions.
Now, when I select OK,
all I have is that one little portion.
And again, I can turn on Discard, select OK,
or I trim out that little portion there as well, so.
Trim Sheet, super powerful tool, great, ultimately useful.
One more thing I do wanna mention.
If I show this surface here, you'll notice I have a body.
I'm just gonna do another trim sheet, pick this.
Boundary, you notice I can pick a body
or a string of body faces and it does calculate
that intersection of where the two touch.
So once again, you can determine, do you wanna keep
or not keep.
I'm gonna cancel this out.
I'm gonna go back to the original trim sheet
and then I'm gonna add that as another boundary.
So you can see that
it does have a lot of options
as far as what you can and can't do.
My preference is basically to try to do as much in one trim
function than to have a stack trim.
So I can go in there and do another trim
and do another trim, but in this case,
it's just really easy to control that stack trim.
So if I wanted to keep these two like that, let me do this,
I can just keep those two just like that.
So great tool, highly recommend
getting very comfortable with it,
again, especially since good modeling technique involves
building large surfaces and trimming them back.