Free-form curves: The key to organic modeling - Rhino Tutorial

- [Dave] We now covered drawing freeform curves, otherwise, known as Dave's keys to organic modeling. Now, there's several ways to draw freeform curves. However, at the end of this, I'm going to recommend you use the control point curve for best results. Let's briefly cover these four types. We have a sketch. This is a very quick and easy, but not that accurate way to draw stuff. We have the handle curve, which is very similar to Adobe Illustrator. We have the interpolate points, which is a weird word, but this draws a curve with points on the curve, as opposed to the control point curve, where the points are off the curve and kind of a cage-like structure. Also, this is the one I'm going to prefer and recommend you focus on. A couple of keys to remember when drawing any kind of curves, but this directly applies to the control points is simpler is better. That means when drawing, use the fewest number of these control points. If you need more detail, just have the points more closely spaced together. Also, we want to avoid loops. This is when a curve crosses over itself or having points stack on top. And remember, you're going to spend more time editing than you do drawing. So don't stress about making that first curve, just assume you'll be moving the control points around to get the exact shape you want. Let's talk about a few editing tips. This is after you've drawn the curve and if turned on the control points to make some additional tweaks. Number one is you can click and drag or use nudge to move these points around. So a couple of ways to do it. If you want more options, there is a Point Edit flyout. We've already used the term control points on. This is a great place for more advanced controls, but we're only going to access one or two of these. The one we will access is if we need to add points to a curve already drawn. We can do that with the insert a control point command. And conversely, if we need to remove control points, there's a command for that, but I find it far easier just to highlight and then hit the Delete key. Okay, let's go through these examples. We'll start off by the handle curve. All these commands are going to be on the curve menu here under Curve, Free-Form and there's the Handle Curve. Now, as I mentioned, this is very similar to Adobe. So we're going to select the point and then it's waiting for us to drag the handle out. Also notice, I have got the end point O snap on, which is kind of important if we want to close this off and finish it up. However, it's still letting me change the angle of that handle. So you do have to right-click to exit the command. That's the handle curve. Now, let's go to interpolate points. As mentioned, this is the points on the curve and it's a little bit unusual if you've never done it. So we'd go to Curve, Free-Form, Interpolate Points. So this shape is formed by the last two points, kind of controlling where it goes. I want to zoom out and just demonstrate that crossover problem I said you should definitely avoid. So here we close it up. So this would be an issue if you went into 3D. That would be a zero thickness wall and you would have difficulty making a prototype or manufacturing. So avoid the crossover or curve loops. Okay, let's try the sketch down here in the left corner. I'm going to go back to the same spot, Curve, Free-Form and Sketch. Like I said, this is pretty easy, but oddly not very accurate. So I'm going to right-click to exit and we can turn this control points on just to check it out briefly. Select the curve, go over to control points on, and you can see there's a lot of crossing and a lot of other issues, but if this were just something for visual feedback, it'd be totally fine. Let's turn those off. I'm going to do this by escaping twice. And we'll end up with a control point. This is the curve type I recommend. And the reason is we typically do editing in this method. So why not create it in the same way? Okay, go to Curve, Free-Form and Control Points. Now this is the one you might've seen over here on the main toolbar. So we talked about having closely spaced points, getting more detail, and then putting the farther part for a smoother curves. So I'm just going to finish this up by snapping to the end point. So don't forget you would never get guaranteed closure, unless that end point snap was on down there at the bottom in the O snap area. Now let's do a little bit of massaging or tweaking. I'm going to select this curve, control points on, and we can move these around. This is the drag technique. We can also select multiple control points and use the arrows. This is the nudge technique. Could hit down Shift to make bigger jumps. Okay. Let's insert a control point. We're going to access some of the advanced features here by clicking on this same icon, holding down to get the fly out and then selecting the title bar right there at the top. It's a little bit difficult. Now you get a brand new toolbar. This can be docked at the top. However, I'm just going to leave it down here or up to the side. Here is the insert a control point. So let's put one maybe right here in the center. Now it lets us do many more. So I do have to right-click to exit. And then you can continue moving these around either individually or in groups. And as I mentioned earlier, we can delete by just picking a control point or more and hitting the Delete key. That is drawing and editing with control points. So remember, control point curves are probably your best bet for any kind of organic 3D models. So keep those curves clean and simple. This will make all the difference and avoiding problems with any surfaces you create.