>> Chapter 21, specifying

three-dimensional
coordinates.

In this chapter,
we're going to work

on understanding
3D drawing,

working with the
3D coordinates,

and working with the
elevation and thickness,

creating a custom

User Coordinate System
for 3D drawing.

Before, we were
working always in

the x and y space or axis.

In this chapter, we
are adding z-axis.

In this Figure 21.1,
as you can see,

on the left image is

a top view or floor
plan of a building,

and the right view
is a perspective.

Working in three-dimensional
environment.

So either you can open
a template file as

acad3D or you can change

the workspace to
three-dimensional space.

Here on AutoCAD,

there is a workspace

and next to the
Quick Access view.

Drafting annotation,

it means two-dimensional
drawing.

Switch that one
to 3D modeling.

You can see the panels

and ribbons are changing.

If you don't have
a workspace,

you can find this
drop-down arrow

and look for
the workspace.

We are now in the
3D modeling space.

Under view, you can

see viewport toolbars

and unsaved view,

or you can see in
the isometric views;

Southwest isometric,

Southeast isometric,
Northeast isometric.

Click on that one. We are

on the Northeast
isometric.

And even the view cube,

you have a chance to
switch the views.

In the 3D modeling,

I'm going back
to Home tab,

we have three types
of modeling; solid,

surface, mesh,

and we are planning
to work on the

solid and mesh
in this class.

Under Home, we have

x and y and
additional z-axis.

Now we are on the World
Coordinate System.

For example, if I draw

a box and change

the visual style
conceptual,

I'm going to change
the coordinate.

Here under the tab, there

is a coordinates panel.

If I change the
coordinates to the front,

can you see the
difference on

the direction
of the x-axis,

and y-axis, and z-axis?

So that's how we

are changing the
coordinates,

and it's called User
Coordinate System.

Switching to the right,
under Coordinates,

I'm going to change the
coordinates to top.

So top is like

a World Coordinate
System for us now.

So the origin is
changing every

time. One more time.

Front, you can
see the x, and y,

and z-axis,
right, x and y,

and z-axis, and left,

top,

and the bottom.

So why do we need access

to change the coordinates?

The reason that
we need to change

the coordinate
is, for example,

if I'm planning to draw

something on
the left view,

from the Home tab
drawing panel circle.

When I move my mouse,
on the left view,

I have a chance to
draw that circle

exactly on the left view.

I'm going back to World
Coordinate System.

I'm changing the
visual style

to 2D wireframe and

now we are going
to start working

on Exercise
AB21-A DWG file.

So from Canvas,
please download

a File AB21-A and
open that file.

And also from the book,

you can see the
steps for drawing

the

3D coordinates,

using 3D coordinates.

So I'm going to
follow the steps

from this book
on Page 664.

On desktop, I
created ENT 135.

So here I have my DWG
Bible book drawing.

There's AB21-A here.

I'm going to open
File AB21-A.

It's an empty file.

So I'm going to
save as this file

back to Assignment

21A-01.

Steps using 3D
coordinates.

Open File AB21-A DWG
from the Canvas site.

This exercise, assume that

you have a dynamic
input turn

on set to the default
of relative coordinate.

The drawing used

a two-dimensional
environment.

It looks like
three-dimension environment.

So I'm going back
to two-dimension.

Save it as AB21-1 in
your assignment folder.

Choose a home type,

drawing panel rectangular,

and create a rectangle.

Start a rectangle
comment at

the specifying first
corner rectangle.

Type 0,

0, 19.

Press "Enter".

At the specified
other corner type

39, 15, "Enter".

This creates a
rectangle 39 units

by 15 units wide.

That is 19 units above
the x and y-plane.

Notice that you omit

the z-coordinate for
the second corner.

Choose a home tab,

modify panel,
copy to start.

We're going to copy

the rectangle two units

above the original
rectangle.

So select the rectangle,

select object,
press "Enter",

and type 0,

0, 2, "Enter".

Press "Enter" to get
out of the command.

You have two
rectangles but

because you are
looking from

top, you see only one.

So we are going to

Home tab view panel

3D navigation
dropdown list

and choose Southeast
isometric.

Now you can see
two rectangles.

If object snap is
not turned on,

click on the
"Object Snap".

Remember object snap?

Set the running object
snap to endpoint.

I'm going to turn off
the rest of them.

Start the line command
and check on here.

We should be following
Figure 21.6.

I'm in the Step 7,

going back to our
figure drawing.

Start Home tab line.

From Point 1,

pick endpoint at Point 1.

So second point or
specifying next point,

type pound, 0,

0, 0, "Enter".

Specifying next point, 1,

0, 0, "Enter".

Specifying next point, 0,

0, 21, "Enter"
and "Enter".

We need to copy
these three lines.

Press "Enter".

From the endpoint,

type 38, 0, 0, "Enter".

Means 38 units
to the right.

I can just copy
those two legs all

the way to the extraction,

to the y direction to
back of the table.

So copy. Either I

can just copy
from here to here

or I could just add 15 for

the coordinates
and it would

copy the legs all
the way to the back.

Actually, it's
a piano bench.

To draw an open cover
for the piano bench,

we need to start a
line again, line.

Start at the
endpoint at Point 2.

Here is a Point
2 from the book.

And specifying next point,

type 15 with the angle of

90 and the angle

of 45. Press "Enter".

And turn on the
Ortho mode or F8.

Make sure you go
straight all the

way and type 39,

is the same way of
drawing a line.

And also, you
can all the way

down and close this door

by finishing with
the endpoint

of the left corner or
Point 3 from the book.

The last line is going
to be the bracing.

This line. So you're

going to have to
start the line.

Starting point is
going to be Number

4 to Number 3,

or you can use coordinates

of 15 with the
angle of 20,

2 as a z-axis.

Press "Enter". As you see,

our drawing is in the
three-dimensional view.

Don't forget to
save your file.