Join Shaun Bryant for an in-depth discussion in this video Polylines and splines, part of AutoCAD 2018 Essential Training.
- [Voiceover] We're staying in the same drawing now, the 04_DrawingObjects.dwg file. You can see all of the elements that we've created so far using the drawing tools in AutoCAD 2017. Things like the ellipse, the circle, the arc of the wall there and the two vertical walls in the top two right-hand rooms of the building. Now what we're going to do now is look at polylines and splines. We're going to create a polylined table, a rectangular table and we're going to extend this little arc wall here with a spline that comes down here and kind of separates the reception areas in the building.
So what we're going to do first of all is make sure we're on the appropriate layer. So let's go to the Home tab on the ribbon, and then the Layers panel, Make sure you're on the I-Furniture layer, which I am already there. Just select the pull down menu like that and select I-FURN like that. Then obviously you're on the right layer to create a table. Now, in previous videos we've used those saved model views. So we'll go over to the view control. Click on the word Top again. Select Custom Model Views and select Reception this time. It will zoom you into the right area.
Now I don't mind where you place this rectangular table that we're going to use with the polyline command. It's just going to be about here. So it could be here, it could be here, it doesn't matter. Just place a rectangular table ideally towards the top of the building though, because we don't want it to clash with our spline that's going to kind of come through here. So let's have a look at the polyline command first of all. Now that is again, on the Draw panel on the Home tab on the ribbon. It's right next door to the line command. So we click on Polyline like so.
Then we come into to drawing area. Now I'm going to zoom in a little bit just for clarity like so, and just pan upwards like that. I'm going to work in this little space here. Now, I'm going to specify a start point, and I'm going to draw this completely freehand. I'm not going to specify a size of table or anything like that. It's just to show you how the polyline command works. It's very similar to the line command, but it just has more features. Then when you've finished a polyline, it closes automatically and becomes one entity, rather than a group of lines.
So I'm going to start about here. I'm going to click there like that, and I'm going to drag across to the right. I'm going to make this 1500. So I'm going to type in 1500 in the distance box and press Enter. Now because I've got my polar tracking on, you see the green dashed line. It does a nice horizontal line there for me. Now what I'm going to do as I come vertically downwards using the polar tracking, because the polar tracking is on, I can now right click and I can utilize the arc option in my polyline command.
So I'm going to select Arc. As I come down, can you see it places a nice arc for me. So I'm going to come down like that and I'm going to type in 1000. 1000 millimeters and press Enter again. It's done me a nice 1000 millimeter diameter arc. Now I want to take my table line now to the left like this. Now it's trying to draw another arc. So what I have to do is right click and go back to the line option on the shortcut menu, just there like that. Now that has gone slightly off the top of the screen.
Don't worry, there's the line option there. So that hasn't disappeared. We're going to go back to the line option in the polyline command and I can line in now with this point here. So I hover over that point there, and because I've got my object snap tracking on, which is down here on the status bar, this one here, make sure that is on. What you can do is you can just hover over that one, and as you come down now, can you see? It lines in for me over that particular point. So as soon as I see that little cross, I can just click and then I can come out. I've drawn those two lines horizontally with an arc.
Now what I'm going to do is I'm going to right click again and select Arc on the shortcut menu. Just come up there to that point there. When I get that end point snap, I click again, and my polyline is finished. I can just press Enter now and there's my polyline. Now the good thing is that is all one object. So I've got a nice table now with curved ends drawn nice and neatly. Now the trick is I can click on that, and what I can do is I can now just right click, select Move, pick a point there, and just move that up slightly like so, so that it doesn't interfere with the spline that I'm about to draw next.
Now, the spline is going to be part of the internal wall. So we go to our layers here, and we go down to the layer pull down here, and we select I-WALL, internal wall, like so. The spline command is available on the Draw panel. Now you'll notice it's not available anywhere on the common icons. You have to hit this little pull out here, and there's more draw tools available. So click on the little pin to pin it open there like that. Here's all our spline commands here. So we've got a Spline Fit, a Spline CV, and so on.
So there's all our spline commands. Now you'll also find on here, if I click here like so, you see I've got rectangle, I've got polygon. So those are also polylines. A polygon and a rectangle are also polylines. So be aware that if you just want to draw a rectangle, use the rectangle command, and that will just create a straight, four-sided polyline for you in the shape of a rectangle. Now, I'm going to go over here to a Spline Fit, this one here. It draws a spline with what they call fit points. The CV is control vertices.
So there's two different ways of drawing a spline. I can either pick points or use control vertices. If I use this one, it will click on Fit Points. Now you'll notice I don't have any points to click on. So really I should be using a Spline CV with control vertices. So if I come over here now, again it's specifying the first point of the spline. So I'm going to use that end point snap there and I click. Now as I come out, can you see as I pick points, can you see the control points? The spline is fitting to those control vertices. So I can create a nice, sort of gentle curve of that line.
Can you see, as I come down. So if I come up again now, it's creating a nice curve. I'm going to come to there like that. Then what I'm going to do is just click one more time. Can you see that? So I'm coming out and I want to click one more time. Now, I can either just stop and press Enter, and that will close the command, or I can just keep going and extending that spline. It creates a nice, gentle curve with those control vertices. What it's doing there is it's actually using a mathematical calculation called a logarithm in the background and it's basically a spline.
It's what they call a Non-uniform Rational B-spline, or NURBS for short. You may hear that commented on when you work in 3D AutoCAD. So I'm going to get to that point now. I'm just going to press Enter once, and it will prompt me now just to close that out. Can you see it's done. So I press Enter and I don't need to worry now. There's my spline. If I click on that, there's all my control vertices. Now what I can do is I can click on these control vertices here. If I click and I drag, I can extend that curve.
Can you see that? So if I click on any of these control vertices, I can control the curve and make it deeper or shallower. So if I take this one a bit further up, there's my nice curve and I can just drag that up this way a bit like that. It's a really, really nice tool for creating gentle curves that you might want to work in. It's also parametric, it's dynamic. So I can click there. I can either change it from a fit like that, and there's my fit points, or I can change it back to my control vertices just by clicking on that triangle there.
So if I change that back to control vertices, they're back like so. I just hit Escape to deselect. So that's how you create a polyline and a spline when you're working in AutoCAD. They can have many, many different uses as well. So just be aware of that and you can work with those and develop some really, quite clever and neat designs using polylines and splines.
- Exploring the user interface
- Using the ribbon, status bar, and ViewCube
- Opening, saving, and closing files
- Setting and converting drawing units
- Navigating drawings
- Saving and restoring views
- Drawing and modifying objects
- Drawing accurately
- Reusing content
- Creating output
- Using PDFs in AutoCAD