>> This is a tutorial illustrating how you would do
the sectioning lab part b of lab number 8.
This is the figure that we're given.
We are given the top and the front view of this 3D object.
Here's the front and here's the top.
And we're asked to create a sectional view corresponding
to the aligned section AA.
So first thing you want to do is to try to visualize the object
by creating construction lines by looking at the correspondence
between features in the top and front view.
So for instance, this construction line here tells me
that this circle is a protruding part based on the top view.
And this construction line here tells me that there's a shell,
this part here is empty, this towards the back here,
the small circle corresponds
to a small circular cylindrical hole towards the back,
and this is a keyway right in the middle corresponding
to those hidden lines in the top view.
Now, to show you what the 3D object is, okay,
I've created a 3D model on the left side here a 3D model,
the isometric of the solid. If I rotate it,
there it is.
Okay, there's a shell on the sides,
and there's a protruding part, and then a key hole
in the middle and three tiny little circles towards the back.
Okay? And we're trying to create the aligned section
corresponding to that cutting plane AA.
And what that means is, imagine cutting it along this planes
and then imagine rotating or aligning the position
of this hole so that it's directly below the center
of the circles.
Okay? So that is an aligned section.
So what we're going to do next is we're going
to start constructing... Here's the aligned section.
This, if I cut it vertically right here, okay,
it would correspond to this sectional view, okay.
And if I join it in order to see what it looks
like on the right side here, as you can see,
we have the hatch areas corresponding
to the solid parts of the object.
And both on top and the bottom, but, so this one is hatched,
this one is empty, this is hatched, this is empty
because of the key hole, this one is hatched.
The main problem here is that we have not aligned the circular
holes on the actual drawing.
Here we need to align the position of the circular hole.
So going to the construction layer, okay,
next thing I'm going to do is generate a whole bunch
of horizontal construction layers and construction lines
by copying this from its current location here
to all the points I see here in the front view, the quadrant
of this circle, the quadrant of this circle, the position
of the center lines of the three little holes, the quadrant
of the circle here, the top of the keyway, the quadrant
of the circle corresponding to the keyway,
more horizontal construction lines matching
to the quadrant here is the location of the center
of the aligned circle, quadrant here and quadrant here.
And then I'm going to continue creating horizontal construction
lines based on all the positions I see in the top view.
And then I'm going to create vertical construction lines
by copying an existing one from its current location here
to all the intersections we might align in order
to find depth dimensions in the right side.
So I have created all the necessary construction lines.
I'm ready to create object lines.
So I'm going to go to the object layer, and I'm going to start
at the upper part corresponding to the shell.
So here in this part is the back part.
So I'm going to create a line.
I'm going to zoom in a little bit
so we can see closer the centers of our screen,
and then I'm going to create a line starting
from the outer shell.
This is the shell part, okay, that goes towards the back.
Okay. And it goes to the top of the keyway, which is this.
Okay. And I'm going to follow the keyway
that protrudes all the way to the front.
Here's the protruding part.
Okay. And then it's going to go all the way
to the solid part of the back shell.
There's the shell and keyway that's protruding.
Then I'm going to go towards, I'm going to create the keyway,
the thin rectangle corresponding to the upper part of the keyway.
Then I'm going to go to the lower part, but before I can do
that I should probably make a copy of the position
of the small circle that I need to align for the align section.
So I'm going to zoom in and copy this circle here,
which is the actual location of the cylindrical hole
from its current position
to this aligned position here corresponding to the quadrant
of that center line for all the circles.
Create horizontal construction lines by copying that to
that quadrant, the upper and the lower quadrants of the copy
of the circle that I just made.
Now I'm ready to create the lower part.
I'm going to start again with the,
let's zoom out a little bit, the shell, okay.
Let's go all the way to the front.
So I start here and go down.
That's the outer shell.
Then it's going to go towards the hole here,
so where the hole starts in the back, okay, and then it goes
down because that's thickness of the back.
Okay? That's another part.
And then I'm going to create the bottom part
of the keyway here is solid, going all the way to the back
and going down until the top of the aligned circle and goes back
and then up and then there's the protruding part.
Then, now, I just need to show this solid lines here.
This line here corresponds to the surface of the shell that is
from the right side be moving away from me,
but it's actually visible.
This is the cylindrical surface of the keyway.
I can see it, but I'm not touching it.
And here's the other part of the cylindrical part of the shell.
And of course, this is the cylindrical part
of the tiny little hole that I align.
I will see, then, all those empty.
Now I'm ready to do my hatching.
Let me make sure that I got the correct hatch pattern.
This is the hatch pattern for steel.
And the 32, and start hatching our solid, by my cuttings there,
so this is solid, solid, solid, solid.
This one is also solid.
Okay. That empty part up there is the shell
that I'm seeing now.
This is the keyway.
Those are all hollow.
Here's solid, solid, solid.
Okay. That's it.
And then we have the hole.
This is solid, and then solid as well.
I think I'm done with my hatching.
So the only thing we need to do now is go
to the center line layers and create the center lines
for the key hole and the hole in the bottom.
But I will leave this up to you to do that and finish the lab.