Getting Started with AutoCAD #2 "Lines using absolute and relative co-ordinates"

Summary

This video tutorial focuses on teaching various methods to draw lines in AutoCAD, emphasizing the use of different coordinate systems. It begins with absolute coordinates, explaining how to use the X and Y axes and the significance of the origin point. The instructor then demonstrates relative coordinates, using the '@' symbol and the importance of sign placement for direction. The tutorial is practical, showing step-by-step line drawing with dimensions to confirm accuracy, catering to beginners learning the basics of CAD design.

Takeaways

• ✏️ There are four different ways to draw lines in AutoCAD: using absolute coordinates, relative coordinates, polar coordinates, and tracking.
• 📍 Absolute coordinates use specific X and Y values to define the location of a point on the CAD screen, with X being left and right, and Y being up and down.
• 🗺️ The origin point in AutoCAD is where the X and Y axes intersect, and coordinates are written as 'X, Y' from this point.
• 💡 Relative coordinates use the '@' symbol to define a point relative to the previous point, requiring knowledge of positive and negative values for directions.
• 🔄 Positive X values indicate a direction to the right, while negative X values indicate a direction to the left; positive Y values indicate up, and negative Y values indicate down.
• 📏 To draw lines with absolute coordinates, enter 'L' followed by 'Enter' on the command line, then specify the starting point coordinates and press 'Enter'.
• 📝 The script demonstrates drawing a line starting from the point (100, 100), using absolute coordinates, with a specified length and direction.
• 🖥️ Relative coordinates are useful for drawing lines based on the last point defined, requiring input like '@50,0' to move 50 units to the right.
• 🔢 The script illustrates using different commands to draw shapes, such as moving vertically or horizontally by defining lengths in the command line.
• 🎥 The next part of the video will cover the remaining two methods for drawing lines: polar coordinates and tracking.

Q & A

What are the four different ways to draw a line in AutoCAD mentioned in the script?

The four different ways to draw a line in AutoCAD are using absolute coordinates, relative coordinates, polar coordinates, and tracking.

How are the X and Y coordinates oriented on the AutoCAD screen?

On the AutoCAD screen, the X coordinate represents left and right, while the Y coordinate represents up and down.

What is the default unit of measurement in AutoCAD?

The default unit of measurement in AutoCAD is millimeters.

How do you specify a starting point for a line using absolute coordinates?

To specify a starting point using absolute coordinates, you input the distance from the origin point in the format of 'x,y' where 'x' is the distance along the X-axis and 'y' is the distance along the Y-axis.

What is the purpose of the '@' symbol when drawing lines with relative coordinates?

The '@' symbol is used to indicate that the coordinates entered are relative to the previous point, not absolute.

How do you draw a horizontal line 50 millimeters to the right using relative coordinates?

To draw a horizontal line 50 millimeters to the right using relative coordinates, you would enter '@50,0'.

What does a positive number signify when using relative coordinates?

A positive number in relative coordinates signifies a movement to the right for the X-axis and up for the Y-axis.

How do you draw a vertical line 20 millimeters down using relative coordinates?

To draw a vertical line 20 millimeters down using relative coordinates, you would enter '@0,-20'.

What does a negative number signify when using relative coordinates?

A negative number in relative coordinates signifies a movement to the left for the X-axis and down for the Y-axis.

How do you end the line command in AutoCAD after drawing a line?

You end the line command in AutoCAD by pressing the 'Enter' key after you have specified the last point of the line.

Outlines

00:00

📏 Introduction to Drawing Lines in AutoCAD

This paragraph introduces the process of drawing lines in AutoCAD, focusing on the use of different coordinate systems. The speaker explains four methods: absolute, relative, polar, and tracking coordinates. The absolute coordinate system is explored first, where the user must consider the x (left-right) and y (up-down) directions on the CAD screen. The origin point, where the x and y axes meet, is used as a reference. The units in AutoCAD are set to millimeters, and the speaker demonstrates how to draw a line starting 100 millimeters to the left and up from the origin point using the 'L' command and entering coordinates directly. The process of drawing a line using absolute coordinates is shown step-by-step, including how to input coordinates and end the line command. The speaker also shows how to add dimensions to verify the line's position and length.

05:02

🔍 Understanding Relative Coordinates in AutoCAD

The second paragraph delves into relative coordinates, which are based on the last point drawn rather than the origin. The '@' symbol is used to indicate relative coordinates, and the speaker explains the importance of using a sign before the number to denote direction (positive for right/up, negative for left/down). The demonstration includes drawing a shape using a starting absolute coordinate of '60,210' and then adding lines relative to that point. The speaker shows how to draw lines to the right, up, and down the screen using relative coordinates, including the use of a negative number to move down the screen. The process is illustrated with step-by-step instructions on how to input the coordinates and the expected outcome of each line drawn, emphasizing the dynamic nature of relative coordinates in shaping a design.

Keywords

💡AutoCAD

AutoCAD is a commercial computer-aided design (CAD) and drafting software application. It is widely used by architects, engineers, and other professionals to create 2D and 3D design and drafting. In the video, AutoCAD is the primary tool being used to demonstrate various methods of drawing lines, showcasing its capabilities in creating detailed technical drawings.

💡Drawing Lines

Drawing lines is a fundamental operation in CAD software like AutoCAD. It is used to create the basic elements of a design. The video focuses on different methods to draw lines, emphasizing the precision and control required in CAD work. Lines are drawn using coordinates, which are crucial for accurate drafting.

💡Coordinates

Coordinates in AutoCAD are used to specify the position of points in a drawing. They are essential for defining the start and end points of lines. The video explains how to use different coordinate systems, including absolute, relative, polar, and tracking, to draw lines accurately.

💡Absolute Coordinates

Absolute coordinates refer to a fixed point in the drawing area, defined by a pair of numbers representing distances from the origin on the x and y axes. In the video, the instructor demonstrates using absolute coordinates to start a line 100 millimeters to the left and up from the origin point, illustrating the precision needed in CAD.

💡Relative Coordinates

Relative coordinates are specified in relation to the last point entered. They use the '@' symbol and are essential for drawing subsequent lines based on the previous point. The video explains how to use relative coordinates to draw a shape by moving 50 millimeters to the right and 20 millimeters up from the last point.

💡Polar Coordinates

Although not explicitly mentioned in the provided script, polar coordinates are another method of specifying points in AutoCAD. They are used to define points based on an angle and distance from a reference point. Polar coordinates would complement the discussion on drawing lines by offering an alternative way to specify positions.

💡Tracking

Tracking, while not detailed in the script, is a feature in AutoCAD that allows users to align new objects relative to existing ones. It is a form of relative positioning that can be used to draw lines parallel or at specific angles to existing lines or shapes.

💡Command Line

The command line in AutoCAD is a text-based interface where users can enter commands to perform various operations. In the video, the command line is used to input commands like 'L' for drawing lines, demonstrating a hands-on approach to CAD operations.

💡Origin Point

The origin point is the reference point (0,0) in a Cartesian coordinate system used in AutoCAD. It is the starting point for all measurements. The video script mentions the origin point when explaining how to use absolute coordinates to draw a line 100 millimeters to the left and up from this point.

💡Dimension

Dimensioning in AutoCAD is used to add measurements to a drawing, showing the exact distances and angles between points, lines, and other objects. The video script includes an example of adding a quick dimension to verify the length of a line drawn from the origin point, demonstrating the importance of accuracy in CAD drawings.

💡CAD Screen

The CAD screen refers to the digital workspace in AutoCAD where drawings are created and edited. The video script describes the orientation of the x and y axes on the CAD screen, which is crucial for understanding how coordinates are used to position elements within the drawing.

Highlights

Introduction to drawing lines in AutoCAD using different coordinate systems.

Explanation of absolute coordinates and their relation to the CAD screen's x and y directions.

Clarification that the X direction is left and right, and the Y direction is up and down on the CAD screen.

Description of how to specify a starting point using absolute coordinates in AutoCAD.

Demonstration of drawing a line from the origin point using the command line.

Use of the Enter key to end the line command in AutoCAD.

Introduction to the concept of relative coordinates and their use in drawing.

Explanation of the '@' symbol's role in specifying relative coordinates.

Illustration of drawing a horizontal line using relative coordinates.

Example of drawing a vertical line using relative coordinates with a negative value.

Tutorial on how to continue drawing a shape using a combination of horizontal and vertical lines with relative coordinates.

Emphasis on the importance of understanding the difference between positive and negative values in relative coordinates.

Overview of how relative coordinates are based on the previously drawn point.

Preview of upcoming video content covering the remaining two methods of drawing straight lines.

Transcripts

so in this drawing I'm going to continue

with my first drawing and I'm gonna add

in some detail and I'm gonna start off

by looking at a few different ways to

draw lines in AutoCAD now I'm just going

to show you that there are actually four

different ways you can draw a line in

AutoCAD using different coordinates

control systems absolute relative polar

and tracking so we look at each of these

four in turn the first one I want to

show you is the absolute coordinates now

with absolute coordinates you have to

consider that your CAD screen has two

directions initially it's a

two-dimensional screen you've got up and

down which is called the x coordinate

and you've got left and right which is

called the y coordinate that's actually

the wrong way around and how I know it's

the wrong way around is that if you look

over here on your cad screen you can

actually see a little X and a Y prompt

down here so the X Direction is left and

right and the Y Direction is up and down

on your CAD screen so a distance from

the origin point is written down as a

number comma a number now the units in

AutoCAD are millimeters so if I were to

start a line 100 millimeters to the left

of the origin point and 100 millimeters

to the north or up the page from the

origin point I'd write it in as 100

comma 100 the origin point is this point

in here where the X and the y-axis would

meet so I'm gonna start by drawing a

line on here 100 comma 100 and I'll show

you how that works so on your command

line when you can draw a line by taking

up here but I prefer to use the command

line it's much easier to remember the

shortcuts so L and enter will bring up

the command line for drawing a line and

you can see as prompting you here

specify the first point so using the

name the number on my keyboard and

typing it 100 and then the comma on my

keyboard and then 100 and when I've

typed in the starting point for the line

I press ENTER and I see my line is

beginning to draw here now so the fixed

point of my line which is kind of over

here to the left hand side that's the

fixed point that's 100

meters to the right of the origin and

100 millimeters up from the origin and

I'm just going to click over here left

click to draw the other end of that line

just in some random spot it's not

important and I don't want to carry on

with this line so what I'm going to do

is I'm going to press the Enter key

which ends the line command now just to

prove that I've got this 100 in here I'm

just going to put on a little dimension

any quick dimension in here and I'm

gonna say from 0 comma 0 to the end of

the line and if I click in here I can

show you that it's 100 millimeters to

the left of the origin point I'm going

to revert that dimension line for a

second and I'm going to put in another

dimension line and I'm gonna go up and

down instead of left and right so in

here again I've got 100 so that line

begins 100 mil to the right the origin

and 100 ml up from the origin now using

that method of inputting a coordinate

it's very common when you're looking at

the starting point for an e shape so

we're going to be looking at some very

basic shapes and this now second

coordinate system we're gonna look at is

relative coordinates and this is where

the coordinates of a pointer entered

well relative to the previous point the

difference this time is we need to use

the @ symbol now you've used that before

it's on your keyboard

anytime you sent an email it would have

used the @ symbol it's the exact same

symbol it's got a button on the keyboard

remember that left and right is the

x-direction and up and down is the

y-direction and the next little

complication that comes in here is that

you have to have a sign before the

number so if it's a positive number it's

going to be to the right if it's a

negative number it's got to be the left

if it's a positive Y number it's gonna

be up the screen if it's a negative Y

number it's going to be down the screen

so let's have a look at how that works

in an example here now with this shape

here the starting point is going to be

an absolute coordinate and the only

absolute coordinate we've got in this

entire shape is up here 60 comma

210 and then I want to draw a line 50

millimeters to the right so I've got at

50 comma zero so what that means is from

this starting point I want to draw at 50

units to the right because it's a

positive number comma zero units up or

down because it's a horizontal line when

I get to this point here I'm going to go

at zero comma 20 which means I want I'm

going to draw the other end of this line

relative to where I am up the screen 20

millimeters but no distance left or

right that's the same kind of thing

until you get to here

where it becomes a little bit different

this is our first negative number so

when we get to this point here our next

point will be down the screen it's zero

left and right because it's a vertical

line and that's minus 20 because it's

down the screen okay so let's have a

look at how that looks

I'm just going to erase this line for a

second so L and enter will start my

command my starting coordinate remember

from last time is going to be 60 comma

210 so I'm going to type in here 60

comma

210 and enter now I can see my line

starting point on the left hand side

there now just as a reminder I'm here

now and I want to draw 15 units to the

right and no units up and down so back

in here on my command line I type in at

50 comma 100 sorry 50 comma zero and

enter and that will drop that has drawn

a horizontal line 50 units long in here

if I look back at what I'm aiming for

I'm now at this point and I want to call

20 units up so I have to type in at 0

comma 20 let's look how that looks so

down here I type in at 0 comma 20 and

enter and you can see that without

actually clicking anything on the

drawing area I'm getting the line drawn

nice and horizontal nice and vertical

so I'm just here now next point is 130

units to the right and zero units up and

down so it's a horizontal line in other

words so back down here where it's

saying to specify the next point I type

in at one three zero comma zero and

enter now I've got a line 130 units long

this is the first place where I've got a

negative number coming in so I just want

to show you that one and the rest of it

is very self explanatory

so I'm at this point and I want to go

down 20 millimeters so at 0 left and

right and that's 20 down so there's some

minus 20 so let's have a look at that

one back in here at 0 comma and on the

keyboard and typing in the minus symbol

20 and enter and I've got a vertical

line that has been drawn down the page

so using that same method you would

carry on and use that shape there to end

up with that shape okay so so far we've

seen absolute coordinates which allow us

to tell the computer where we want to

start and we've seen relative

coordinates which tell the computer

where do we want to go based on what

we've already drawn we start here we

wanted to go 50 mil to the right we got

it here we wanted to go 20 mil up we got

to here we wanted to go 130 ml to the

right we got to here we wanted to go 20

meltdown so every coordinate you put in

is based on where you've already drawn

to so in the next little video clip I'm

going to go and do the next two ways of

drawing straight lines