Join Rob Garrott for an in-depth discussion in this video What is HyperNURB modeling?, part of CINEMA 4D Essentials 6: HyperNURB Modeling and Sculpting.
In a previous module in the Essential Training Course, we looked at how to model a speaker cabinet using polygon modeling techniques, and spline modeling techniques. That type of modeling works fantastic when you're trying to create inorganic shapes with things that don't have smooth edges. But what happens when you do need to make something that feels organic, or has smooth edges? That's where the HyperNURB object comes in. A HyperNURB is a special type of object in CINEMA 4D that smooths out whatever you put under it. Let's take a look at that. I'm going to add a cube to the scene.
A cube has some very hard edges to it. I'll add this little guy right here; the HyperNURB. When I click on that, I get a HyperNURB object. The icon for the HyperNURB object is green. That means it's a generator object, and it needs to have a child, or multiple children in order to produce some sort of result. So if I take the cube and drop it under the HyperNURB, then I get a sphere-like object. What exactly is happening here? Let's switch our view to the four-way by middle mouse clicking.
I'm holding my mouse over each of the views, and then hitting letter H. Now that I've got the objects filled up in each of the frames, let's change the Display options. Let's go to Display, change it from Lines to Gouraud Shading (Lines), so we can actually see the lines on the surface of our object. Do Display > Gouraud Shading (Lines), and Display, and Gouraud Shading (Lines). What the HyperNURB does is take whatever you put under it, and it examines the midpoints along each of the edges on your object.
It then draws an arc between the midpoints on each of the edges on your object, and it does that in all three dimensions, all at once. So if we look at this cube here that we've placed under the HyperNURB, and I'm looking at in the Top view; in the Top view, there's a midpoint along each edge, and that midpoint is right here. The next midpoint in the Top view is an edge right here. So the HyperNURB object draws a smooth arc between those two points. It does it again on the other side, and again here, and again here.
And then in the Front view, it does it around in this axis, and it does this around each of the axes, in each of the views, and it does that in all three dimensions at once. So what you end up with is a sphere-like device. I say sphere-like because it's not truly spherical. In order to get a round shape with the HyperNURB object, you need to have more than four sides. And so, because our cube is only four-sided, you're only going to get a sphere-like object. Now, every time we add a subdivision to this cube, we're going to get a different shape, because the midpoints will have changed.
So if I select the Cube object, and I go to the Object Properties, and I'm going to adjust the Segments. Let's adjust the Segments along the Z-axis, so we'll see the change in our Top view. So I go to the Z Segments, and change it to, say, 5. As soon as I do that now, all of my midpoints have changed. My midpoints around the Y-axis, though, so along X, have not changed. So I've got one midpoint way over here, and then another midpoint right about here, and that's why I get this short curve.
From midpoint to midpoint along the side, I get no curve at all, because the midpoints are all evenly spaced and flat along the X-axis. The general rule of thumb when you're modeling with HyperNURB objects is that every time you make a cut, or you add detail to your model, you're going to have to do some revisions to it. It's a very fluid and intuitive way to work once you understand the basics. Here are some great examples of objects that are simple to make that I've created with the HyperNURB object, and we've got a very simple fish shape here.
And this fish started out life as a simple cube, and I'm going to select the main body. I'm in Texture mode right now. Let's click on the Model mode, and go to the Display, and tell it Gouraud Shading with Lines. You can see that I've got a lot of polygons here. If I turn off the fish NURB for a second, these are the actual polygons that are being smoothed out by the HyperNURB object. The HyperNURB allows you to create a low-res mesh, and then smooth it to generate a much higher res result. There are some controls in the HyperNURB that allow you to do that.
If I click on the HyperNURB object, and look at the Subdivision Editor, and Subdivision Renderer, those two fields control what the fish looks like here in this window, and also what it looks like in the Render window. When I subdivide it lower here, I'll do a 1 on the Subdivision Editor, my Subdivision Renderer is still pretty high at 3. That means I'm going to get three subdivisions for every one subdivision here. That's going to give me a lot of polygons, and in fact, if I turn on the HyperNURB, and I look at the polygons that I'm getting, you can see that this polygon count that I have here represents what I'll see in the Editor window.
Now when I render that, I'll see the subdivisions in Renderer. And if I hit Shift+R on the keyboard, just to render the picture viewer, you can't really tell in this view, because the fish is already pretty smooth. And that's a really important point to make is that the HyperNURB object has a point of diminishing returns. You only want to add as much geometry to your object as you absolutely need at the time that you need it, because it's very hard to get rid of the geometry once you have it in your model. Now, when I change the Subdivision Editor from 1 to 3, I now have the exact same subdivision as what I'll see when I render.
And you can see there's a lot more polygons. And this polygon count can get very heavy to pull around. So that's what this Subdivision Editor field is for; it allows you to lower the resolution here, so that you don't have to haul all that geometry around, and then when it comes time to render the frame, you'll get the higher resolution geometry. It's a much better way to work and allows for a lot of flexibility. Now, HyperNURB modeling works fantastic for truly organic shapes, like this fish, but there are times where you want to make some inorganic shapes out of HyperNURBs. If I go the Window menu, and look at Hypernurb-type- START, this Hypernurb type is a type element that I created using the HyperNURB object.
I modeled the letters of this type logo. You may be asking yourself, Rob, why didn't you simple extrude? The reason I didn't simply extrude is because I wanted to have very clean quadrangle-based geometry. If you do just extrude your logo, then you'll be left with whatever geometry you get out of the Extrude NURB object. And that's one of the problems; when you extrude a piece of type, the geometry that you get is not very clean at all. By modeling my type with the HyperNURB, I get very clean geometry. Let's take a look at that. When I select an object, you can see that I've got a very clean piece of geometry.
Let's switch to the Move tool. Now we can see that we've got a representation of how these polygons are distributed across the surface. This curvature of lines that you're seeing here is something called Isoline Editing mode. This mode allows you to preview how the polygons are being distributed across the surface based on the HyperNURB. Now, I don't normally like to work this way. I prefer to work with Isoline Editing off. Let me show you what that looks like. We go to the Options menu, and I'll uncheck Isoline Editing, and now we see the low poly mesh around the high poly geometry of the HyperNURB object.
So the light blue stuff represents the RG Merged object, and then the gray stuff is the HyperNURB itself. HyperNURB Modeling is an awesome technique to use when you need to create objects that have smooth surfaces, or soft transitions between edges. With the polygon tools that we've talked about in a previous module, combined with the HyperNURB object, you can create just about anything you could imagine.
- What are HyperNURBS?
- Setting up reference shapes
- Creating a shape with the polygonal modeling tools
- Connecting shapes and bridging gaps
- Refining shapes with knife cuts
- Moving points
- Working with sculpting layers
- Preparing objects for render