Getting Started with AutoCAD #2 "Lines using absolute and relative co-ordinates"
Summary
TLDRThis 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
📏 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.
🔍 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.
Mindmap
Keywords
💡AutoCAD
💡Drawing Lines
💡Coordinates
💡Absolute Coordinates
💡Relative Coordinates
💡Polar Coordinates
💡Tracking
💡Command Line
💡Origin Point
💡Dimension
💡CAD Screen
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
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