Join Dave Schultze for an in-depth discussion in this video Building Turtle Boy using Surface From Curve Network, part of Rhino 5 Essential Training.
In this next video, we will dig deeper into the most powerful surface command al over Rhino, the surface from a curve network. If you didn't know, this is the command that can build amazing organic forms that nothing else can, but that's the good news. The bad news is, it's easily the most difficult command in Rhino to master, but once you've figured out, every thing else in Rhino will seem so much easier. Before we starting building turtle boy, let's review the final goal, and cover the basic rules.
Okay, I've got the screen with a lot of pretty colors here, and we're also in ghosted mode. So we can see through. So let's highlight the rules before we talk about what we're looking at. Rule number one, you want to think of the curve you are building for this command as iso curves. Rule number two, each direction should be matching. So it's going to be open or closed, but it can't be mixed. Finally, rule number three, one of the direction needs to be open, due to the scene. So now let's take a look. The blue curve's here, and the iso-curves that I've created I'm going to select just two of these guys.
We're just going to call that the long direction of the two. So you'll notice that those are individually open. They're going to form a close surface when done. Those curves are individually open. Now go in the other direction, which we'll call the short direction, these are all closed. So we've met all the criteria. And if you're wondering, we've got some little red lines here. And those are just construction lines. So we'll be building those separately, and explaining what they do as we go along. Okay, the next new wrinkle is something called picture frame.
I've already got one of them installed. This is a very handy command when you're doing organic or complicated surfaces. You can bring a photograph of a sketch or pretty much any image, and it'll create a surface and map it on for you. So, you can see what our form is fitting up pretty nicely. Let's go ahead and built a picture frame going the opposite direction, so we can capture those profiles when we build. So it's under Viewport Layout. There's the picture frame. Now I've got one for the front view. I'll select that.
Before I place it, you have to note which Viewport you're in. We're in perspective, the construction plane is laying flat. So we're going to have to select Vertical. It might have been easier to do it from the front view. I'm going to go ahead and keep it in perspective. So we're going to snap the corners. Then hold down Shift, so I go straight off to the side. Now, I know they're not the same size, or even registered. But one thing I want to point out at this point, is that I've created these both square, that makes things much easier to move them around. I don't have to worry about the differential scaling.
So that we'd end up with things getting squashed or stretched. So the scale then becomes very easy. I'm going to select this second one we did. You go to a 3d scale command. I'm going to snap on the first corner. That's the one we want to stay. And then the second corner will be modified, and we'll just snap up to the original. Okay, so it's still not in the final position but we're getting close. I'm going to go ahead and select and use the Move command. Now I've got the mid snap on. So make sure yours is also selected.
So I'm going to go from one mid point to the other mid point. Getting close. I think this actually needs to be nudged back just a little bit, so I'll probably give it a couple clicks, with the, shift + arrow key up. It looks pretty good. So you can see how helpful this will be, once we start tracing curves and building this from scratch. Now one last thing, this picture frame is kind of blocking my view. So I'm going to select both of these planes, and go down under the properties and you'll find this.
It's a little bit difficult to find because there's a lot of options. But we've got transparency. So I'm going to dial those both down to about 50% plus or minus. And finally, I'm just going to have it lock the picture frame layer. So I want to be able to move those guys out of the way accidentally, which can happen very easily. So there's our picture frame. We've got our final drawing already there. Now let's build it from scratch. I'm going to turn that back off. And start in the side view. It doesn't matter which view you start at.
Curve from object. We're going to start with a control point curve. General rules are that more detail requires points being closer together. Another general rule is, I don't try and be too careful the first time. I definitely want to finish it up, and then do some tweaking. It's almost impossible that you have this thing perfect the first pass, so don't even try.
Okay, not too bad. Go ahead and do a little bit of editing, F10 will turn the control points on. (SOUND) And you just nudge him just a little bit. I'm not going to do too much here. I think that'll do it. Let's just make sure we didn't snap to anything accidentally.
I'm going to go back to the perspective view port. And look around. Yes, we had a snap. It looks like it jumped to the middle of this plane accidentally. So let's go ahead and turn the control points off and fix that right away. So go to the view where it looks correct, and that's the right view, and we transform project to C plane. And question comes up the command line, delete the inputs, say yes. So check that out in perspective view. We flattened it back out nicely.
This happens all the time when you're trying to trace objects. Other things in the scene will cause snapping back and forth. So you can just use this to project a C plane to fix it very quickly and easily. I turn this picture frame off just for a second. this looks like why it got in our way. It's on the wrong layer. So I want to move that over. Okay, so this is now a closed curve. When I showed you the final goal layer. That was all open in that one long direction.
So let's go ahead and split these out. This will actually give us some nice editing points here, when we go the opposite direction. So I do the split command. The split is that profile. Right-click and then this little access line already drawn, with the cutting object. So those are in two parts. Now I'm going to do some construction lines. Just a few quick and easy ones. To do this, the best way, I'm going to need one more toolbar. So I'm going to right-click, show toolbar, and this is called lines.
And what I love about this guy, is this one command here. This is the line from the mid point. So we're going to zoom in here, we're going to snap that intersection. Holding down shift, we're going to make some construction lines. We're going to use here very shortly (SOUND) The same thing at the bottom. (SOUND) And okay. So, why did I draw those? Well I've got to avoid the pinch coming into this connection.
Where all these curves will be diving into like the North Pole. So, the way I do that is put up construction lines. Turn the control points on. Get rid of some of the smaller ones there. And then just snap these points. Maybe with perpendicular on. We'll get those right on there. And if they're a tiny bit off you have to zoom in a bit. If we have too many points we just delete. So the goal is here as they come in, to the north pole, they're in alignment.
Remember the last two points should be in the same alignment. Let's do the same thing at the bottom. Actually this is too close, you might want to move it away, then move it back, that's actually a good little trick. Get rid of the ones that are a little bit too tight. 'Kay, once they snap down, you can actually keep moving them with the Nudge tool. Whatever works to maintain the overall shape and form of this profile.
Okay, let's get the picture frames back on. Let's draw the profiles going the other way. So I'm going to do another freeform curve. Actually I'm going to escape that command and switch view ports. Definitely want to be in ortho views here. Also we're done editing so we hit F11, turn our control points off. I'm going to maximize this front view here. Okay, another 12 point. Actually, I'm going to back to perspective to start it.
This is why we do a lot of jumping around with organic models. So the first two, I want to alignment. And I'll come back to the front viewport. Again we're going to trace the body fairly quickly. Going to make some edits as needed. So here's our construction line right down there. I should probally go back to perspective to finish it. There's a lot of stuff going on now.
Okay. Let's check it out. Front view looks pretty close. Turn the control points on, going to do one or two little bit of tweaks. I think we should let it go at that. Now the good news is, it's symmetrical, so we can go ahead and mirror this over to the other side. F11 to turn it off. Actually our picture frame, I think we're pretty much done with it for this portion. Go ahead and turn that off.
Make things a lot easier, so I'm going to select that side profile. This will be a transform mirror. So I'm just going to use these construction lines as my snapping. Okay, so there we've got the one direction, which I'm just calling the long direction defined. Now we need to get curves going in the opposite direction. So that can be a real trick. So I'm going to show you this really cool command. You have to use it in all four view ports, though. Zoom in, I'm going to be building at kind of the side view, but I need to have perspective open for this to work.
So the command is located on the curve menu. It's called the curve, cross-section profiles. And it's now asking me to select the profiles that it's going to be crossing. In order, and that means we have to go one direction. So, I'm just going to pick one at random, and just go around. Right-click. And now this is where we need to go into the right view port. Now this is going to be creating kind of a laser line. We're going to pick somewhere, and then holding down Shift, go all the way to the opposite end and pass it.
So what happened, in perspective, you can see it's created a curve that touches all of those items. Except we didn't modify the setting, so this always happens. We have to get rid of that guy, now let's repeat that command. Cross-section profiles. We're going to pick them in order. I'm going to start with the front. Here's all four. Closed equals No. So let's switch that to Close equals Yes. I'm going to start outside.
I'm going to pick a logical point where want an extra iso-curve going here. It looks good to me. So right-click to exit there. Let's check this out. So Rhino's actually pretty smart. We've got, what looks like some complicated math going on. Turn on the control points, check it out. Only problem I see though, is the shape is defined by the barest minimum of control points. We have four, and I can't really do much editing without this thing completely missing the curves going the other direction.
No problem. Turn the control points off F11. going to select that profile, and just Edit > Rebuild. And some more points. Very easily. I think ten points will be enough. Start off with four. OK to accept. Turn the control points back on. So I'm going to kind of move my view up here and, and I think I want his nose to be a little bit less sharp. So I'm going to move those guys up together.
Maybe these two a little bit, not quite as much. And then sense it's missing. Let's just grab the group of three. And nudge those back so it gets close. It's not critical that these touch exactly. Rhino was going to interpolate, and so if the two curves miss each other, it'll actually build the surface right in between. Need to make this a little wider, two, three, four. I always try to match this if it's going to be symmetrical. One, two, three, four.
I think that is good enough. For a turtle boy body and head. Now, we'd make the other two profiles the exact same way. I already have those done. So they're on the hidden layer. So we turn those control points on, just take a quick look. So those are pretty clean and very close. I think we're ready. Go to Surface > From Curve Network. Now, it usually doesn't matter which order you pick them in. But I like to just keep things organized. It will matter for more complicated shapes.
So I've picked the first direction as a set and then the second direction. When you get this, after hitting right-click or Enter. This means you are pretty much done. All we have to do is a little bit of tweaks. So, that is the shape. Now, we're still in, ghosted view. So you get to see right through it. But it's also potentially a little bit complicated. So, normally you would just hit OK, and after a certain point in time, or maybe you had some problems, you would do Edit > Rebuild, and make this a smoother shape.
But, we can actually lower the tolerance right now before we complete the command. So I'm going to knock a few decimal points off here. So instead of it having to be a 1,000th of a millimeter accurate. I'm going hey, this is just an organic shape. I could be pretty loose. So we could just the preview off, and back on again. And it gets much simpler, so it'll actually help us with problems in the future, if we're making small details. Let's hit OK. And switch to Shaded View here.
Just to check it out. So the surface from curve network command will definitely take some practice to understand and master, but it's totally worth it. Some tips if things don't go your way. Make sure you've identified two directions, that they match being opened or closed, and they're simple as possible. Also try your surface with fewer curves or not as many profiles and see if it works that way.
- Why use Rhino?
- Understanding 3D terminology
- Comparing Bézier curves, B-splines, and NURBS objects
- Navigating the viewport
- Manipulating objects with commands
- Creating curves, surfaces, and solids
- Performing basic transformations
- Making solids with primitives
- Extruding curves
- Snapping to objects and planes
- Trimming, splitting, rotating, and copying objects
- Working with NURBS and seams
- Prototyping a 3D model