Lines and polylines - Rhino Tutorial

- [Instructor] We now review a few ways to draw and join simple lines. First, it's important to know the difference between a line or a line segment and a polyline. The line segment is simply a line that has not been joined, so that means the polyline is joined, and it can have two or more segments, there is no limit. Now, here's the really cool part. You can change from single line segments to a polyline any time with the join command, and as you were just about to ask me, yes, you can go backwards with the explode command, which is basically another way to unjoin. We're gonna check out both of these. Let's first start off by looking at a couple ways to draw lines. I've got the line toolbar open here, but all the stuff can be accessed up here, as well, under curve, line, single line, and we're just gonna draw the two endpoints, anywhere you want, that's a basic line. Let's now try to get a little more advanced and draw multiples, so I can go over to these polyline. This time, I'm gonna right click and click on segments, so as we draw this shape here, it looks like they're all connected, however, we picked segments, so they're not connected. That means, if I go to the same command, left click, I will get this line endpoints joined together. I can verify this by highlighting, that all ligihts up, or I can just look up at the command line, it says one curve was added to the selection. Over here in properties, it's a single open curve. Now, as you just witnessed, any time endpoints are touching, it's easy to join. That means that this example right here, which crosses and they do touch, but they do not share endpoints, so no, that cannot be joined. Let's explore this idea of joining a little further. I've got multiple curves here. Looks like they're all sharing endpoints. Let's verify that by drawing a box around all four and going over to the join command. This is on the edit menu, or we can do the shortcut here and use the icon for join, little puzzle piece lookin' guy. Now, I can verify that this works by looking at the command line, four curves joined into one closed curve. That's really what you want. You could also look at properties, it says closed curve. Now, if I hadn't joined it, maybe I was opening up a file from someone else, I can verify this just by clicking on it, noting over here it says closed curve. So far, so good, let's check out this one here. Interesting, it says it's open, but it looks the same. What's going on? Now, this is a very common situation with beginners. We'll dive into this to show you exactly what happened. So, just to highlight the importance of using endpoint snaps whenever you're drawing, this can happen. A lot of times, it looks like they're closed or touching, when in fact, there's a tiny overlap or a tiny gap. Now, this can cause real problems later in prototyping and manufacturing, so you always wanna make sure if something's supposed to be closed, make sure you use those osnaps and you close it up. There's also a fix, here, I'm gonna select this whole entity, and I'm gonna turn the control points on over here on main toolbar. Now, depending on how far you're zoomed in or out, you may have to drag one of these curve points away, and then, with the endpoint osnap on, bring it back. So, watch for that little popup cursor tool tip, it does say end, I can let go, I have fairly good confidence that this is now joined up, but just to be sure, I'm gonna turn off the control points by right clicking there, we're gonna zoom out, and then one more time, just click here, over at properties, it does say closed, so that was a successful repair mission. Here's a couple examples of joining, let's talk about the opposite, which is explode, and we find it pretty much in the same spot over there next to join, so I'm gonna click that button with the left mouse button. We have four separate pieces, and the coolest thing of all is we can just select them again and join them right back up. So, this process is just about unlimited. You can go back and forth as much as you want. Okay, let's take a look at a little super Dave tip. I've got a closed polycurve here, I'm gonna click on it, it lights up, it's a single closed curve, now we know how to explode and make it into a bunch of different pieces, however, I just wanna remove this one piece here. I'd like to get something different around the closure. What can I do? Well, let's do a little bit of a sweet hack by selecting, we're gonna explode, now, command line tells me it's 20 segments. I'm gonna deselect the one I don't want holding down control, select that short piece we talked about earlier, now with everything still selected, I'm gonna hit join, or Control + J, and that's a great way to get parts popped out or exploded out, or extracted from a very complicated set of otherwise connected pieces. Let's wrap it up with a couple different curves. I'd just like to highlight the ability to use osnaps and some other techniques to get things exactly where you want. I'm just gonna draw a very simple single line. Now, a lot of times, with curves and arcs, you have the center on, so you have to watch out for that, 'cause any time you click the edge, it's always snapping to the center. That may not be where you want it, so be aware of when that's on or off, and arcs also have midpoints, and they also have quadrants, it's a very common way to connect to things, and I can draw, in any direction. Typically, if it's gonna be straight, horizontal, or orthogonal, I'll just hold down the shift key. That's usually a quite a faster way to draw. Two of my favorites are the perpendicular from and to, go up to the curve menu here, we'll do a line that is perpendicular from one curve, just wanna click over here, now, once I've clicked, it let's me slide up and down, and notice that little tangent, there. That's giving me the perpendicular point to start from, so I can just click here, and now as I draw away, that just slides with me, changing the angle as I go. So, that was pretty cool, it may be even cooler to do that with two separate curves, let's try that out. Curve, line, and then tangent to two curves. Don't forget, there's a lot of options in here, but we're only gonna check this one more, but notice you have a lot of ways to draw a curve. So, tangent to curve, we're gonna select the smaller circle on the bottom and then kinda correspondingly position to the larger circle. Boom, a nice tangent. So, watch out, a lot of times people select in the wrong spot, I'm gonna right click to repeat, picking the same lower end, but then, the top part for the larger circle, so notice how those were connected. So, if you get the wrong result, start over, or pick two new sets. So, Rhino gives you this ability to start drawing and creating anywhere, then you have the ability to convert from one type of curve to another and back. So, remember, join to connect, explode to disconnect.