In this video, we're going to talk about how to add curves, line, and spirals to an already existing alignment. Then we're going to go ahead and actually use what we're talking about and add a couple of curves to our existing alignment inside of this drawing. So first what you need to be able to do is get back into the alignment creation toolbar, it's associated with the alignment that's in the drawing already. If you were to drop down and choose Alignment Creation Tool, you're going to go ahead and actually create a new alignment. So what you have to do inside Civil 3D is you need to go to the alignment that you have created, select it, and then click on Geometry Editor. So inside of Geometry Editor, it brings up the alignment creation toolbar that's associated with the specific alignment that's already in the drawing. So one thing we didn't talk about in the last video that's an important piece of the editing abilities of your alignment creation toolbar, is that you have a grid view of your alignment. So inside of here if you click on this where's there's alignment grid view or you can do as you can see all of the information related to your alignment, what type of item it is, what the parameters are, what the start and end points are, and that information. If it's locked, obviously you can't change it, but you can unlock it. But when you unlock it, it doesn't really allow you to change any of the objects inside of here and that's simply because these are all interacting with each other. So if I modify a direction or a length or a start and end station of one object, it's going to cascade through the rest of the alignment and modify bunch of other things and you don't want to have that happen. So for now, it's all empty when we add our curves and we'll go back into here and you'll see that there are some items available to be modified inside of this grid view. So what we're going to do is we're going to jump down into the options for adding information to our alignments. So the first reactions are you can add a point of intersection, you can delete a point of intersection or you can break a point of intersection. These options just basically are going to either dissolve that point of intersection and move the line in between the existing start point and that point of intersection, or it'll add a new one and it will change the tangency between two existing point of intersections, or if you break a point of intersection, it's going to get rid of the links between the point of intersection. So if I broke this point of intersection, it would remove the two links between that point and this point. We're not going to deal with those. What we're going to deal with is we're going to deal with adding lines, curves, and spirals. So what is important to note inside of adding lines, curves, and spirals is there are three prefixes to the type of curve, line, or spiral that you're going to add, and those are fixed, floating, and free. They're not necessarily the most intuitive names for how you're dealing with things. But what you need to realize is that a fixed curve or a line or a spiral, what fixed means is that you are placing that object based on fixed points. So you will click all the defining points for that entity. A floating entity has one end that is connected to an object inside of Civil 3D and other end is being connected to a fixed point. So say we wanted a floating line, it would basically create a line that was tangent to an already existing curve or going from the end of an existing curve, and then you would pick the end point of that line. So the line floats along the object until you pick the endpoint. Same thing with the curves. You float along the object until you pick the endpoint. That's the why floating is chosen as the name of a floating curve and floating line. When we talk about free curves and free lines, what free curves and free lines are is they're actually going between two existing objects inside of Civil 3D. So a free curve is between two tangents or another curve and a tangent. But you go between existing entities and you either choose a radius or a through point. With the lines, you're going between two curves, basically. So you're going with one curve tangency and then creating tangency to the next curve. Then with spirals, it's the same thing, except for what spirals are as you spiral into a curve and then you spiral out of a curve or you spiral into another curve and then spiral out of that curve. But spirals are very specific and I don't use them very often, they're very design-specific as well. So you're most likely going to be seeing lines and curves in your day-to-day design practices. So moving on from here, we're going to go ahead and actually add some free curves. So we're going to take our dropdown for our curve. We're going to choose free curve between two entities and a radius. So what Civil 3D is going to ask is it's going to say specify your first entity. My first entity is this tangency here, my next entity is this tangency here, and we are going to be asked, is the curve solution greater than 180 or less than 180? So does the line have basically outside of this or inside of this? We're doing an inside curvature. So we're going to go ahead and choose inside are less than 180. So I'm going to hit Enter, and then it's going to ask me what I want my radius to be. I could also choose curve length, tangent length, chord length, mid ordinate distance, external degree, and then degree of curvature. I'm going to go ahead and go with 60 foot radius curve, and I'm here enter and it now places to curve in here, it's tangent to that section and this section. Then I'm going to go ahead and do it again. It says specify first entity. I'm going to select this tangency, and I'm going to select this tangency. So when I select it on the polyline that we have here not the alignment. So that's one thing you need to be aware of is draw order inside of Civil 3D. I have to hover over my actual alignment and select the tangency. Now I get a choice of curves solution angle. I'm again choose less than 180, so I'm going to hit Enter and then I'm going to again choose 60 as my radius, and so I'm going to hit Enter, and we have now placed two free curves into our alignment.