Arcs

there will be many times when you need to draw an arc an arc is a portion of a circle or an unclothed circle when a circle object is broken it becomes an arc there are many ways to draw an arc make sure to pick the one that suits your situation the best I’m going up to my file tabs I have them open for this time right click on the file tab area and click open
browse to this section and look at the file called arc examples and open that one
so here we have some line work already created for us a bit of a little caliper or bracket and a series of lines and other things here that we have so we have this line work set up for us so that we can go ahead and work right in with our circles now the art command defaults to the three point method it’s similar to the three point method when drawing a circle let me show you by completing some of these things here so if we go to the Home tab on the ribbon and into the draw panel see here there is a button for the arc and if we click this flyout we get a lot of different ways to draw an arc typically though you’re going to use the three point command and it creates an arc as you see here in the example using three
different points and they’re numbered one two and three and that’s the order in which you create them one two three so the number one is first number two a second and then third is your last you can start the arc command just by typing in the letter A and press Enter
now I’m going to complete this thing here I’m going to snap to my end point I went to type in end
snap to it there’s my first point that’s where I’m starting from now I can click anywhere so I’m going to click just right here and as you can see it holds the first and second point the arc will always start at the first point and pass through that second point that we picked now the arcs shape its radius its length etc will depend on where I put this third point at and I can put it anywhere and as you can see the arc changes dramatically depending on where that third point is I’m just going to snap to the endpoint of here
there you go
and once you create an art you can see here that it can be stretched the radius can be changed you can do a lot of different things to it so if I just grip at it here it’ll bulge it out some more I can click and edit here and move it around I can even change the center this is like using the Move command press escape to let go of the arc so that’s the basics of an arc the majority of the time that’s all you’re going to need are those three points I’m sure you noticed when I started the arc command there was a center option so when we start the arc command in the command line you can see here are some more options arc specify start point of Arc or Center so I can start the arc command at the center point so I’m going to click Center or type in the letter C now the arc is asking me for the center point I’m going to pick the end point of this shape here so that’s my center of my arc and I’m drawing now my start point so I’m going to click here with my end command for my snap when a snap to that end point so it’s starting at my same start point I had before but at this defined radius so as I stretch my cursor left or right it draws the circle I’ll notice wherever I start from by default a circle or an arc are drawn in a counterclockwise
direction zoom out a little
as I spin around to increase this angle which I can just pick anywhere or I can type in the amount of degrees that I want that angle to be it goes in a counterclockwise direction now if I hit the ctrl key on my keyboard and hold it down it will toggle to the other
direction it will now go and clockwise so this is what you have to do it used to be before in an AutoCAD that you had to know where to start to get the right angle in you know the right direction but this is a change that’s happened in more recent AutoCAD versions so this is a really nice thing so you can create something that goes to the end here and now it looks like I have this pac-man hooking shape so that’s a nice little option this will make your first point the center point of the arc and it will make you draw all sorts of arcs so now you have two ways to draw an arc from a start point to a point in between and then to an end point or now you can start at the center and get your start and finish points and at that defined radius now you don’t always know these points that’s what’s great about the arc command the majority of what you’re going to need for your arc command or the two that I just showed you but let’s look at some of these they’re going to make sense they’re very straightforward so remember to go to the ribbon go to the Home tab and into the arc if you click on this button here you’ll get a quick definition of how these arcs are going to be created so we saw the three-point arc we also have a start center end this creates an art using a start point center point and an end point now it’s a little bit different so if I click start Center end now it’s asking me for my start point so I’m going to snap type in E and E to this point here
and I’m going to create an arc that stretches all the way across here now it’s asking me for the center point now there are options here that I can use in my command line you may have more tools available to you by following the command line right now it’s asking me for the center point so I’m going to type in cen to snap to the center point of this arc right here because I’m going to parallel it you can see the little o snap coming up click it there and now I’m going to draw my arc now it would come on this side here but because by default remember it starts where you first pick your start point and then the arc is drawn in a counterclockwise manner hit the f3 button to toggle on my oh snaps that way I know I’m going to automatically snap to this endpoint but I want the arc to come the other
direction so I’m going to press and hold the control key and now it toggles the direction of the arc this makes drawing the arc much more easy snap to there and I’ve created that arc I’m going to delete this one so we can see a little better so I was able to create that arc right there without any issue I didn’t have to make any measurements I didn’t have to know any radius I didn’t have to know where the center point was no coordinates no length nothing I was able to fill in that arc exactly the way I wanted to do I could do the same thing with these circles here with this same command so I need to find my start point it’s going to be there and my center point which is going to be here in this case I’m going to have to hold down the ctrl key again and snap to right there and I was able to finish that it’s a very useful command so if I went with my regular three-point arc but I hit c-4 Center enter again
to start at this center point use this from my start point I have the radius I have the center point it’s just in a little bit different order and I can control it again
very useful and again you don’t always have all the points you need so you just need to go through some of these another one you have here is the start center angle it creates the art using a start point the center point and you put in the angle I want a start point let’s say I’m going to start here and now it’s asking me for the center point of the arc right here
and it’s asking for the angle now if I know what that angle is I can type it in but if I don’t I can just snap to that point there it goes
so a lot of these are variations on a familiar theme or on the same sort of theme what these commands are doing for you is that they’re macros if I start with a three-point arc creation command I can start at an endpoint or I can start at a center point so if I start at the center point by either typing in the letter C or by clicking on the command line the center option I’m now drawing something from the center I’m going to start from the midpoint of this line now I have options I need to start points I want to start here at the endpoint and now I can just click down here and it draws my arc I can type in the degrees that I want or I can go by a chord length so I can click here for angle or L for length L then it’s not asking for an angle anymore it’s asking for a length and this will give me the length of that chord which is this line right here so if you understand how circles are made and you understand the
definitions of angle chord arc length etc you’ll be able to use the arc command in a lot of different ways now you can also hit a start end
direction so if I click a point here hit my center point and then specify an end point for my arc I can do one of these things this is a nice option if you want to create a bit of a smooth arc so if I click here click here that defines my cord now I can come and draw this in a lot of different ways I can match this line here and it gives me a nice little symbol you can do a lot of different things with it we’ve looked at several of these different our commands this is your standard 3 point this group uses the start and center and then varies on that this one uses the start in the end and then it’ll go by angle direction or radius and these here start you at the center point then go to a start point and then we’ll go by end angle or length so depending on what you have and what you know and what you’re trying to create that will determine which one of these are creation commands you want to use like I said the majority of the time your 3 point arc is going to be fine now another command option that you have in here is called the continue so if you have an arc just any arc anywhere made by any of the methods shown and then you want to continue that arc but with a different arc you can use the continue option what this does is draw an arc tangent to the last arc that you’ve made or to another line so if I click here you can see this is very sinuous tangent to each other I have a line drawn I want to continue that line but with an arc so I come up to the arc command here in the ribbon and go to continuous and it makes an arc that is tangent to that line now when you use all of these other commands and you hit the enter key it will restart the arc command but it won’t restart any of these special arc commands that you’ve used that will only restart this regular three-point arc command so in the case of this
continuous if you want to keep using it you’re going to have to keep going back to this continue arc command option so keep that in mind when you just press ENTER to restart the arc command it won’t give you your specialized
variations of the arc command it will just give you the basic three-point arc of creation command and also remember if you draw and it’s in the wrong direction that’s okay press and hold the control key and that will flip it around that can be very annoying when you’re trying to create an arc and you see that I’ve done it wrong it’s okay hit the control key and pull it down and that will flip it around the direction and that’ll solve your issue there