Sweeping rails - Rhino Tutorial

- We now check out the rail sweep commands. These come in two flavors, the 1-rail sweep and, you guessed it, the 19-rail sweep. Just kidding, there's only 1-rail and 2-rail. But both can create surfaces that are flat and mechanical or smooth and organic. We'll explore each with these demos right down below, starting with the 1-rail sweep. We can find the command under the surface menu, sweep 1-rail. Once we select the rail, we don't have to right click or hit Enter to accept. Now we proceed to select the cross section curve. Make sure you click a corresponding point, like at the top or the bottom, but don't switch up. So otherwise you get twisting. I'm going to select this other one down here. Now, since I only want those two, I'm going to right click to proceed, and we get a nice clean curving wall. Which, by the way, since it's a single surface, we can always turn on control points and continue to edit. I'm going to turn those off and delete this. We're going to try another little variation. I'm going to go up to the command line, right click, and then select sweep 1-rail. That's a great way to repeat stuff, by not finding the command each time. Same rail. This time we'll select the curving profile and the one that looks fairly straight. Right click to accept, hit OK. And this looks pretty clean. Just like the other one. The trick is matching the number of control points. Let me move this out of the way just by dragging it. And I'm going to highlight the first profile and that very last one, turn the control points on. And now we can see why I got such a clean surface. So you definitely would expect four or five or six control points on that first curve. The second one, most people would have drawn with just two end points, but I used the same number of control points and thereby made a much smoother and clean shape. So that's a great rule to follow. If you can, make the profiles very similar in the number of control points. Moving along to the 2-rail sweep, where to find this in the same area. Surface, sweep 2-rails. We're going to pick both, no need for the right click, but we do have to do the same thing with the profiles. I'm going to select 1, 2, 3 at the same general top area. Right click to accept. Now you'll notice that this surface looks quite a bit more complex. In fact, I want to cancel out of this and explain that additional curve, both on the top and in the middle generate the additional complexity. Let's see if we can back up a bit and make this a little cleaner by omitting this center profile. So up at the top, right click to sweep 2-rails. So I pick the bottom and the top, then the cross sections. Just the two end ones. Right click to accept. And much simpler and cleaner. I'm going to hit OK to accept that. And you'll see, even though there was more input geometry, it came out almost as clean as the other one with less curves. Let's now proceed to work on the spacecraft. I'm going to turn on this spaceship geometry. Console and console curves. We'll be doing our work on the console layer itself. So that should be your new current layer. Let's zoom up here and take a peek inside. So I've got a dashboard I want to sweep around here, but I don't want to get too close to the window. So I've drawn this one curve here that pulls away from the window. It's very important to me that I don't block my view in flying the spacecraft. Now we've got the support, which is kind of short here as it gets close to the wall. But as the dashboard pulls away, the support is extended. Maybe a little hard to see. So we'll turn off the ship geometry layer and just do these two sweeps one at a time. Let's go to surface, sweep 1-rail. I'm going to pick the lower curve here since it pulls away from the wall. And then the cross section is that dashboard shape. Right click to accept. Now, if you have a single rail and a single profile, the seam doesn't matter. So you can just blow right through. Right click to accept, then hit OK. So that is pretty cool. And we can see how it pulls away, following the rail. The shape stays the same, the rail guides where it goes. Now for the support, I've made three separate profiles on each end. They're a little bit shorter. And in the middle, it extends out to bridge that gap. Let's go ahead and repeat the command. We can go up to surface, sweep 1-rail. Now I'm going to use this top curve which followed the hole more precisely. Pick the profiles now, in the same general spot, which is at the top. And you'll notice I'm in perspective almost all the time, just so I can make sure I pick the right stuff. This is really difficult when looking at it from a top or side, things will stack up and get very confusing. But I've got those three picked, I'm going to right click to accept. That should be okay. So I'll just go right through. And there you see the difference. With additional profiles, you can kind of modify. the shape as it goes along the curve. Let's turn the ship back on. So when working with these rail sweeps, whether mechanical or organic, you still want to keep all the curves involved as simple as possible. Finally, keep in mind that you can add extra profiles if needed.