Loft Generator Demystified: Caps without Caps, Point Order and Open Splines

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In this Video, I will show you a few more things relating to the Loft Generator, and specifically making Caps without... Caps, how the Point Order of the Profile Splines affect the Mesh Generation, and how the Loft handles open Splines.



In this video, I will show you a few more things relating to the Loft Generator, and specifically, making caps without caps, how the point order of the profile splines affect the mesh generation, and how the loft handles open splines. In this fairly simple bottle, which is constructed solely by circles, I want to add a cap at the bottom. Now, what I could do is select the Loft Generator, go to the Caps tab, and set the End to Cap or Fillet Cap. And let me set this to N-gons. But what if I want this to be slightly rounded? Well, in that case, I need to make one more circle copy. So I'm going to CTRL or CMD - Drag and make it a sibling and go to my scale tool and scale it down and so forth. And you'll see that it bulges out and that creates this nice rounding, and then it flattens out to the cap. But there is a slightly easier solution. Just make that copy of the circle. Make sure that your Caps are off. Yes, off. We are going to create a cap without actually capping the Loft Generator. Select the last object, and just make the Radius zero. And because this is going to create a zero point, you will see that you get really nice rounding, and it rounds all the way here. Let's go and see this model from the inside. So let's zoom in, and you will see that it has a nice, clean rounding as you would expect it to. Now, there's an alternative way to this. Instead of making a circle... Let's delete this. What you can do is go to your spline drawing tool, click once to create one point, and then Esc. And then go to your Live Selection, select that point, and zero out its position so it coincides with the axes, and use that single point as your last spline. And you're going to get exactly the same result. Now, let's talk about point order. So I'm going to deactivate the Loft Generator, and I'm going to select all my circles, and I'm going to press C to make them editable. When I go to points mode, you will see that all splines have this white to blue gradient. And this means that the spline begins here at point zero, goes counterclockwise, and ends here. White to blue. That's how the point order is. Now, what happens here is that because all our points here are starting from the same position, that's why we have this nice geometry flow. In any case, if I take any one of these circles and I rotate it around, you will see that the mesh tries to follow that particular point order. So, in this case, you will see that the mesh is going to go from here to here, and then back to here, and that's why we get this S shape. The same thing applies... And let me undo a couple of times. Good. The same thing applies if you select a spline and you set a different starting point. So I'm going to go to my Live Selection tool, select this point, and then I'm going to right-click and Set First Point. This is going to move the beginning of the spline to that point. Now, if I activate my loft, you will see that we get this twisted looking bottle, which may or may not be what you're looking for. But in either case, you need to remember that the starting points need to be aligned if you want your mesh to be aligned. Now, another thing I'm going to show you... And I'm going to undo a couple of times to make it as it was. What if I get a spline and reverse the point order? So I'm going to right-click and Reverse Sequence. Now, you're going to see we're going to get a flip in our mesh because now, not only the beginning has shifted by one, but it's going clockwise instead of counterclockwise, and this is what the geometry is trying to do. It's going counterclockwise, and then it tries to go clockwise, and that's why we get this fold. So it goes from here to here, all the way back. I'm pretty sure you will never need a model like this. Hey, but if you do, please let me know. I'm very curious about it. Another thing I want to talk about in this video is open versus closed splines. Now, to do that, I need to select these guys here and press C to make them editable. As you know, each spline in the Object tab of the attributes has the Close Spline button. If I turn everything off, you will see now, we have an open bottle. This is how the splines look, so it only makes sense to do this. But what if only one is open? So let me select this one, this one, and these three and close them. You will see that the Loft Generator tries, as much as it can, to create this form. But the only problem here is that now, we have the points changing position. So what you see here is that this is where all the splines begin. Let me select one so you can see. The colors go to point mode, so here's where they start. So you can see that the geometry goes all the way around nicely for every single one of the splines. But the one that's open, you can see it finishes here. So this is where the last polygon is going to go. So if you're trying to make something which is half open and half closed, well, this is the way to do it. Now, there's one more ramification when it comes to open splines and caps this time. Let's go and activate the top cap, and I'm going to turn it to N-gon so it's nice and clean. The Loft Generator can only cap the mesh if the capping spline is closed. So if I select this one and I open it, you will see that the cap disappears because it doesn't make sense to try and close an open spline. So just make sure that if you're capping something, it needs to be closed.
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