Subtitles of the Movie

Let's now look at the AutoCAD Coordinate System in a little bit more detail. What we've done so far, we've drawn our circle at a center of 50, 50 and with a diameter of 40 and we've drawn a line from the center of that circle that is 100 units long using the Direct Distance Entry Method with Dynamic Input. Now Absolute and Relative Coordinates, when you type them they can be in the form of an Absolute Coordinate which is relative to 00 which is shown by the X and Y on the screen with a little cross in the box or they can relative to another point. So what I could do here is I could utilize perhaps my Object Snaps which will cover later but I might ant to draw a line from the end point of say my line on the screen or the center of the circle. I can also place it at an Angle if I want to using both Absolute or Relative Coordinates. So let's have a look at that in more detail, I'm going to go back to the Line Command now. So I'm going to click on the Line Command and come into the drawing area. Now AutoCAD is prompting me to specify the first point. Now what I could do there is I could use Object Snaps and select the right hand end point of my line. But I could actually calculate those coordinates in my head if I wanted I know that the left hand end of the line is at 50, 50 and I know that the right hand end of the line is 100 units to the right. So we need to add 100 to the X value. So the coordinate of the right hand end of the line is actually 150, 50. So if I now type in my first point at 150 there in the first box and press the Comma Key and then type in 50 in the Y coordinates and press Enter its an Absolute Coordinate again, relative to the 00. But the next point now is going to be relative to the end of that line so it's not at 00 anymore. So what I can specify here is I can actually type in the coordinate that I want to go in that, I want it relative to that. So let's say I want it to be 25 units from the end point to the right hand end point of the line. So I want it 25 along to the right which is positive in the X direction and then 25 upwards which is positive in the Y direction. I can type the At Symbol that will tell AutoCAD that it is a Relative Coordinate. Relative to the last point selected. So at the specify next point prompt now if I type At AutoCAD now goes into Relative Coordinate Mode. Notice there I can specify an angle. See the less then symbol, less then 66 degrees, that at the moment is prompting me for an angle. I'm not going to put an angle in there I'm going to put a coordinate in there. Watch. 25 I then press the Comma Key and notice it goes to Coordinate, input I type in 25 again. So now are saying to AutoCAD from the end point of that line go 25 along and 25 up. If I press Enter now you can see there the next line segment is being prompted for but I've gone 25 along to the right and 25 upwards. That is a Relative Coordinate using X and Y Coordinates. However I can also draw using angles, you notice that Angle Symbol in the previous Relative Coordinate. So let's do, let's do another Relative Coordinate by typing At and as you can see there's the prompt and there's the angle there, can you see that there? Yeah? So what I'm going to say to AutoCAD now is I want to align a specific length. So I'm going to say that I want a line 45 units long and then if I type in that symbol, that less then symbol which is Shift and then the Comma Key AutoCAD then takes me into Angle Mode and that Angle there I want it to be 45 degrees but going upwards and to the left, that will be in AutoCAD terminology a 135 degrees. So notice this look, as soon as I put the number in there a 135 degrees, press Enter and there's my line. So my line is a 135 degrees but is that particular length that I put in. So you can see that I can input either Absolute Coordinates using X and Y Coordinates. Absolute Coordinates using Polar Coordinates with an angle. I can also do that in a relative setting as well. So what we've got there now, let's just have a quick overview. We've utilized the Command Line, we've utilized the Coordinates System with Polar, Absolute and Relative Coordinates. We've also utilized the Dynamic Input which we're going to look at in more detail and we've also utilized Direct Distance Entry. Now all of this information regarding the Absolute and Relative Coordinates is available on page 47 of the AutoCAD 2009 Essentials Manual provided by Autodesk. The Autodesk Official Training Courseware, AOTC Courseware, this can be obtained from the Autodesk US website. Let's have a look now at Dynamic Input.